common file format & media formats specification
TRANSCRIPT
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CommonFileFormat&MediaFormatsSpecificationVersion2.1
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CommonFileFormat&MediaFormatsSpecificationVersion2.120February2015
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CommonFileFormat&MediaFormatsSpecificationVersion2.1
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Notice:Asofthedateofpublication,thisdocumentisareleasecandidatespecificationsubjecttoDECEMemberreviewandfinaladoptionbyvoteoftheManagementCommitteeofDECEinaccordancewiththeDECELLCOperatingAgreement.Unlessthereisnoticetothecontrary,thisspecificationwillbecomeanadopted“EcosystemSpecification”on12April2015.THISDOCUMENTISPROVIDED"ASIS"WITHNOWARRANTIESWHATSOEVER,INCLUDINGANYWARRANTYOFMERCHANTABILITY,NONINFRINGEMENT,FITNESSFORANYPARTICULARPURPOSE,ORANYWARRANTYOTHERWISEARISINGOUTOFANYPROPOSAL,SPECIFICATIONORSAMPLE.DigitalEntertainmentContentEcosystem(DECE)LLC(“DECE”)anditsmembersdisclaimallliability,includingliabilityforinfringementofanyproprietaryrights,relatingtouseofinformationinthisspecification.Nolicense,expressorimplied,byestoppelorotherwise,toanyintellectualpropertyrightsisgrantedherein.Thisdocumentissubjecttochangeunderapplicablelicenseprovisions,ifany.Copyright©2009‐2015byDECE.Third‐partybrandsandnamesarethepropertyoftheirrespectiveowners.OptionalImplementationAgreement:InadditiontotheUltraVioletLicenseAgreementswhichcoverimplementationoftheDECEEcosystemSpecificationswithintheUltraVioletEcosystem,DECEoffersanoptionallicenseagreementrelatingtotheimplementationofthisdocumentoutsidetheEcosystem(“RANDAgreement”).EntitiesexecutingtheoptionalRANDAgreementreceivethebenefitofthecommitmentsmadebyDECE’smemberstolicenseonreasonableandnondiscriminatorytermstheirpatentclaimsnecessarytotheimplementationofthisdocumentinexchangeforacomparablepatentlicensingcommitment.CopiesofthelicenseagreementsareavailableattheDECEwebsitereferencedbelow.ContactInformation:Licensingandcontractinquiriesandrequestsshouldbeaddressedtousat:http://www.uvvu.com/uv‐for‐business
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CommonFileFormat&MediaFormatsSpecificationVersion2.1
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Contents 1 Introduction..................................................................................................................................................................................12
1.1 Scope......................................................................................................................................................................121.2 DocumentOrganization.................................................................................................................................121.3 DocumentNotationandConventions......................................................................................................121.4 NormativeReferences....................................................................................................................................131.4.1 DECEReferences.........................................................................................................................................................131.4.2 ExternalReferences...................................................................................................................................................13
1.5 InformativeReferences..................................................................................................................................151.6 Terms,Definitions,andAcronyms............................................................................................................161.7 Architecture(Informative)...........................................................................................................................191.7.1 MediaLayers.................................................................................................................................................................191.7.2 CommonFileFormat.................................................................................................................................................201.7.3 TrackEncryptionandDRMsupport...................................................................................................................201.7.4 VideoElementaryStreams......................................................................................................................................211.7.5 AudioElementaryStreams.....................................................................................................................................211.7.6 SubtitleElementaryStreams..................................................................................................................................211.7.7 MediaProfilesandDeliveryTargets...................................................................................................................21
2 TheCommonFileFormat........................................................................................................................................................232.1 CommonFileFormat......................................................................................................................................232.1.1 DigitalCFFContainerStructure............................................................................................................................262.1.2 DCCHeader....................................................................................................................................................................272.1.3 DCCMovieFragment.................................................................................................................................................302.1.4 DCCFooter.....................................................................................................................................................................32
2.2 ExtensionstoISOBaseMediaFileFormat............................................................................................342.2.1 StandardsandConventions....................................................................................................................................342.2.2 ContentInformationBox(‘coin’)...................................................................................................................352.2.3 AVCNALUnitStorageBox(‘avcn’)................................................................................................................372.2.4 SampleEncryptionBox(‘senc’)......................................................................................................................382.2.5 TrickPlayBox(‘trik’).........................................................................................................................................392.2.6 ClearSampleswithinanEncryptedTrack........................................................................................................412.2.7 StoringSampleAuxiliaryInformationinaSampleEncryptionBox......................................................41
2.3 ConstraintsonISOBaseMediaFileFormatBoxes.............................................................................422.3.1 FileTypeBox(‘ftyp’)...........................................................................................................................................422.3.2 MovieHeaderBox(‘mvhd’).................................................................................................................................422.3.3 HandlerReferenceBox(‘hdlr’)forCommonFileMetadata...............................................................432.3.4 XMLBox(‘xml’)forCommonFileMetadata...............................................................................................432.3.5 TrackHeaderBox(‘tkhd’)..................................................................................................................................432.3.6 MediaHeaderBox(‘mdhd’).................................................................................................................................442.3.7 VideoMediaHeader(‘vmhd’).............................................................................................................................442.3.8 SoundMediaHeader(‘smhd’)............................................................................................................................442.3.9 SubtitleMediaHeaderBox(‘sthd’)......................................................................................................................45
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2.3.10 DataReferenceBox(‘dref’).........................................................................................................................452.3.11 SampleDescriptionBox(‘stsd’)................................................................................................................452.3.12 ProtectionSchemeInformationBox(‘sinf’)........................................................................................452.3.13 DecodingTimetoSampleBox(‘stts’)....................................................................................................452.3.14 SampletoChunkBox(‘stsc’)......................................................................................................................452.3.15 SampleSizeBoxes(‘stsz’or‘stz2’)...................................................................................................462.3.16 ChunkOffsetBox(‘stco’)..............................................................................................................................462.3.17 TrackExtendsBox(‘trex’)...........................................................................................................................462.3.18 MovieFragmentHeaderBox(‘mfhd’)......................................................................................................462.3.19 TrackFragmentHeaderBox(‘tfhd’).......................................................................................................472.3.20 TrackFragmentRunBox(‘trun’)..............................................................................................................472.3.21 SegmentIndexBox(‘sidx’)..........................................................................................................................472.3.22 MediaDataBox(‘mdat’).................................................................................................................................472.3.23 TrackFragmentRandomAccessBox(‘tfra’)......................................................................................47
2.4 Inter‐trackSynchronization.........................................................................................................................482.4.1 Mappingmediatimelinetopresentationtimeline........................................................................................482.4.2 Adjustingaudiosyncframeboundarymisalignments................................................................................48
3 EncryptionofTrackLevelData.............................................................................................................................................493.1 MultipleDRMSupport(Informative).......................................................................................................493.2 TrackEncryption..............................................................................................................................................50
4 VideoElementaryStreams......................................................................................................................................................514.1 Introduction........................................................................................................................................................514.2 DataStructureforVideoTrack...................................................................................................................514.2.1 TrackHeaderBox(‘tkhd’)..................................................................................................................................514.2.2 SampleDescriptionBox(‘stsd’).....................................................................................................................514.2.3 TrackFragmentRunBox(‘trun’)...................................................................................................................524.2.4 MovieFragmentBox(‘moof’)............................................................................................................................524.2.5 AccessUnit.....................................................................................................................................................................524.2.6 RandomAccessPoints..............................................................................................................................................53
4.3 AVC.........................................................................................................................................................................534.3.1 StorageofAVCElementaryStreams...................................................................................................................534.3.2 Constraintson[H264]ElementaryStreams....................................................................................................54
4.4 HEVC......................................................................................................................................................................564.4.1 StorageofHEVCElementaryStreams................................................................................................................564.4.2 Constraintson[H265]ElementaryStreams....................................................................................................57
4.5 Sub‐samplingandCropping.........................................................................................................................594.5.1 Sub‐sampling................................................................................................................................................................594.5.2 CroppingtoActivePictureArea............................................................................................................................604.5.3 RelationshipofCroppingandSub‐sampling...................................................................................................614.5.4 DynamicSub‐sampling.............................................................................................................................................64
5 AudioElementaryStreams.....................................................................................................................................................665.1 Introduction........................................................................................................................................................66
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5.2 DataStructureforAudioTrack..................................................................................................................665.2.1 TrackHeaderBox(‘tkhd’)..................................................................................................................................665.2.2 MovieFragmentBox(‘moof’)............................................................................................................................665.2.3 SyncSampleBox(‘stss’)....................................................................................................................................665.2.4 HandlerReferenceBox(‘hdlr’).......................................................................................................................675.2.5 SoundMediaHeaderBox(‘smhd’)...................................................................................................................675.2.6 SampleDescriptionBox(‘stsd’).....................................................................................................................675.2.7 SharedelementsofAudioSampleEntry......................................................................................................68
5.3 MPEG‐4AACFormats.....................................................................................................................................685.3.1 GeneralConsiderationforEncoding...................................................................................................................685.3.2 MPEG‐4AACLC[2‐Channel]..................................................................................................................................695.3.3 MPEG‐4HEAACV2[5.1,7.1‐Channel]...............................................................................................................715.3.4 MPEG‐4HEAACv2.....................................................................................................................................................755.3.5 MPEG‐4HEAACv2withMPEGSurround........................................................................................................77
5.4 MPEG‐H3DAudioFormat............................................................................................................................795.4.1 StorageofMPEG‐H3DAudioElementaryStreams......................................................................................795.4.2 MPEG‐H3DAudioElementaryStreamConstraints.....................................................................................79
5.5 AC‐3,EnhancedAC‐3,MLP,AC‐4andDTSFormatTimingStructure........................................805.6 DolbyFormats...................................................................................................................................................805.6.1 AC‐3(DolbyDigital)...................................................................................................................................................805.6.2 EnhancedAC‐3(DolbyDigitalPlus)....................................................................................................................825.6.3 MLP(DolbyTrueHD).................................................................................................................................................865.6.4 AC‐4...................................................................................................................................................................................88
5.7 DTSFormats.......................................................................................................................................................895.7.1 StorageofDTSelementarystreams....................................................................................................................895.7.2 RestrictionsonDTSFormats..................................................................................................................................94
6 SubtitleElementaryStreams.................................................................................................................................................966.1 Overview..............................................................................................................................................................966.2 CFF‐TTFormat..................................................................................................................................................976.2.1 Definition........................................................................................................................................................................976.2.2 CFF‐TTTextEncoding...............................................................................................................................................976.2.3 CFFTimedTextProfiles...........................................................................................................................................976.2.4 CFF‐TTCoordinatePlane......................................................................................................................................1066.2.5 CFF‐TTExternalTimeInterval...........................................................................................................................108
6.3 CFF‐TTSubtitleEventandVideoFrameSynchronization...........................................................1086.4 CFF‐TTEncodedImageFormat...............................................................................................................1086.5 CFF‐TTStructure...........................................................................................................................................1086.5.1 TrackFormat.............................................................................................................................................................1086.5.2 SampleFormat..........................................................................................................................................................109
6.6 CFF‐TTHypotheticalRenderModel......................................................................................................1106.6.1 FunctionalModel......................................................................................................................................................1116.6.2 TimingModel.............................................................................................................................................................112
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6.6.3 ImageSubtitles..........................................................................................................................................................1166.6.4 TextSubtitles.............................................................................................................................................................1176.6.5 Constraints..................................................................................................................................................................120
6.7 DataStructureforCFF‐TTTrack............................................................................................................1206.7.1 Introduction...............................................................................................................................................................1206.7.2 TrackHeaderBox(‘tkhd’)...............................................................................................................................1206.7.3 MovieFragmentBox(‘moof’).........................................................................................................................1216.7.4 MediaHeaderBox(‘mdhd’)..............................................................................................................................1216.7.5 HandlerReferenceBox(‘hdlr’)....................................................................................................................1216.7.6 SubtitleMediaHeaderBox(‘sthd’).............................................................................................................1216.7.7 SampleDescriptionBox(‘stsd’)..................................................................................................................1226.7.8 Sub‐SampleInformationBox(‘subs’)........................................................................................................1226.7.9 TrackFragmentRunBox(‘trun’)................................................................................................................1226.7.10 TrackFragmentRandomAccessBox(‘tfra’)...................................................................................122
6.8 SignalingforCFF‐TTTracks......................................................................................................................1226.8.1 TextSubtitleTracks................................................................................................................................................1226.8.2 ImageSubtitleTracks.............................................................................................................................................1236.8.3 CombinedSubtitleTracks....................................................................................................................................123
6.9 SubtitleLanguageConsiderations..........................................................................................................1236.9.1 Overview......................................................................................................................................................................1236.9.2 RecommendedUnicodeCodePointsperSubtitleLanguage.................................................................1246.9.3 ReferenceFontFamilyperSubtitleLanguage.............................................................................................1276.9.4 TypicalSubtitlePracticeperRegion(Informative)...................................................................................127
6.10 ClosedCaptionSubtitlesTranscodedfromCEA608orCEA708..............................................129AnnexA. CFFParameters.........................................................................................................................................................130AnnexB. MediaProfiles............................................................................................................................................................131B.1. PDMediaProfile............................................................................................................................................131B.1.1. Overview................................................................................................................................................................131B.1.2. ConstraintsonEncryption..............................................................................................................................131B.1.3. ConstraintsonVideo.........................................................................................................................................131B.1.4. ConstraintsonAudio.........................................................................................................................................132B.1.5. ConstraintsonSubtitles...................................................................................................................................132
B.2. SDMediaProfile.............................................................................................................................................134B.2.1. Overview................................................................................................................................................................134B.2.2. ConstraintsonEncryption..............................................................................................................................134B.2.3. ConstraintsonVideo.........................................................................................................................................134B.2.4. ConstraintsonAudio.........................................................................................................................................135B.2.5. ConstraintsonSubtitles...................................................................................................................................136
B.3. HDMediaProfile............................................................................................................................................138B.3.1. Overview................................................................................................................................................................138B.3.2. ConstraintsonEncryption..............................................................................................................................138B.3.3. ConstraintsonVideo.........................................................................................................................................138B.3.4. ConstraintsonAudio.........................................................................................................................................139
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B.3.5. ConstraintsonSubtitles...................................................................................................................................139B.4. xHDMediaProfile.........................................................................................................................................140B.4.1. Overview................................................................................................................................................................140B.4.2. ConstraintsonEncryption..............................................................................................................................140B.4.3. ConstraintsonVideo.........................................................................................................................................140B.4.4. ConstraintsonAudio.........................................................................................................................................141B.4.5. ConstraintsonSubtitles...................................................................................................................................141
B.5. UHDMediaProfile.........................................................................................................................................142B.5.1. Overview................................................................................................................................................................142B.5.2. ConstraintsonEncryption..............................................................................................................................142B.5.3. ConstraintsonVideo.........................................................................................................................................142B.5.4. ConstraintsonAudio.........................................................................................................................................143B.5.5. ConstraintsonSubtitles...................................................................................................................................143
B.6. HDR10MediaProfileDefinition..............................................................................................................145B.6.1. Overview................................................................................................................................................................145B.6.2. ConstraintsonEncryption..............................................................................................................................145B.6.3. ConstraintsonVideo.........................................................................................................................................145
B.7. DolbyVision(“DV”)ProfileDefinition..................................................................................................146B.7.1. Overview................................................................................................................................................................146B.7.2. ConstraintsonEncryption..............................................................................................................................146B.7.3. ConstraintsonVideo.........................................................................................................................................146
B.8. HDR12MediaProfileDefinition..............................................................................................................148B.8.1. Overview................................................................................................................................................................148B.8.2. ConstraintsonEncryption..............................................................................................................................148B.8.3. ConstraintsonVideo.........................................................................................................................................148
AnnexC. DeliveryTargets.......................................................................................................................................................150C.1. GeneralDownloadDeliveryTargetConstraints...............................................................................150C.1.1. ConstraintsonFileStructure.........................................................................................................................150C.1.2. ConstraintsonVideo.........................................................................................................................................150
C.2. Multi‐TrackDownloadDeliveryTarget...............................................................................................152C.2.1. Overview................................................................................................................................................................152C.2.2. ConstraintsonFileStructure.........................................................................................................................152C.2.3. ConstraintsonEncryption..............................................................................................................................152C.2.4. ConstraintsonVideo.........................................................................................................................................153C.2.5. ConstraintsonAudio.........................................................................................................................................159C.2.6. ConstraintsonSubtitles...................................................................................................................................159
C.3. Single‐TrackDownloadDeliveryTarget..............................................................................................161C.3.1. Overview................................................................................................................................................................161C.3.2. ConstraintsonFileStructure.........................................................................................................................161C.3.3. ConstraintsonEncryption..............................................................................................................................161C.3.4. ConstraintsonVideo.........................................................................................................................................161C.3.5. ConstraintsonAudio.........................................................................................................................................161C.3.6. ConstraintsonSubtitles...................................................................................................................................162
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C.4. Pre‐PackagedDeliveryTarget.................................................................................................................163C.4.1. Overview................................................................................................................................................................163C.4.2. ConstraintsonFileStructure.........................................................................................................................163C.4.3. ConstraintsonVideo.........................................................................................................................................163
C.5. StreamingDeliveryTarget.........................................................................................................................164C.5.1. Overview................................................................................................................................................................164C.5.2. ConstraintsonFileStructure.........................................................................................................................164C.5.3. ConstraintsonEncryption..............................................................................................................................164C.5.4. ConstraintsonVideo.........................................................................................................................................164C.5.5. ConstraintsonAudio.........................................................................................................................................165C.5.6. ConstraintsonSubtitles...................................................................................................................................165C.5.7. ConstraintsonAdaptationSets.....................................................................................................................166
AnnexD. InternetMediaTypeTemplateandParameters.........................................................................................168AnnexE. TheDECEFileFormat............................................................................................................................................169E.1. DECEFileFormat..........................................................................................................................................169E.1.1. ExtensionstotheCommonFileFormat..........................................................................................................169E.1.2. ConstraintsonISOBaseMediaFileFormatBoxes.....................................................................................171E.1.3. Constraintson‘ccff’Boxes............................................................................................................................171
E.2. MediaProfiles.................................................................................................................................................171E.3. DeliveryTargets.............................................................................................................................................171E.3.1. Multi‐TrackDownloadDeliveryTarget..........................................................................................................172
E.4. InternetMediaTypeTemplateandParameters..............................................................................172E.5. FileExtensions................................................................................................................................................172E.6. DECEInteroperabilityPoints...................................................................................................................172
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Tables Table2‐1‐BoxstructureoftheCommonFileFormat(CFF)..............................................................................................24Table2‐2–Additional‘stsd’Detail:ProtectedSampleEntryBoxstructure........................................................26Table2‐3–TrackIDAssignment....................................................................................................................................................30Table4‐1–AccessUnitstructureforpictures..........................................................................................................................52Table4‐2–ExampleSub‐sampleandCroppingValuesforFigure41‐...........................................................................62Table4‐3–ExampleSub‐sampleandCroppingValuesforFigure43‐...........................................................................63Table5‐1–DefinedAudioFormats...............................................................................................................................................67Table5‐2–bit_rate_code....................................................................................................................................................................81Table5‐3–chan_locfieldbitassignments..................................................................................................................................84Table5‐4–StreamConstruction.....................................................................................................................................................92Table5‐5–CoreLayout.......................................................................................................................................................................93Table5‐6–RepresentationType.....................................................................................................................................................93Table5‐7–ChannelLayout................................................................................................................................................................93Table5‐8‐ChannelLayoutExt..........................................................................................................................................................94Table6‐1–CFFGeneralTTMLFeatureRestrictions...........................................................................................................100Table6‐2–CFFGeneralTTMLElementRestrictions.........................................................................................................102Table6‐3–GeneralTTMLAttributeRestrictions.................................................................................................................103Table6‐4‐CFFTextSubtitleTTMLFeatureRestrictions.................................................................................................104Table6‐5‐CFFTextSubtitleTTMLSMPTEExtensionRestrictions.............................................................................104Table6‐6‐CFFImageSubtitleTTMLFeatureRestrictions..............................................................................................105Table6‐7–CFFImageSubtitleTTMLElementRestrictions............................................................................................106Table6‐8‐CFFImageSubtitleTTMLSMPTEExtensionRestrictions.........................................................................106Table6‐9–ConstraintsonSubtitleSamples..........................................................................................................................110Table6‐10–HypotheticalRenderModelConstraints........................................................................................................120Table6‐11–RecommendedUnicodeCodePointsperLanguage..................................................................................124Table6‐12–SubtitlesperRegion................................................................................................................................................127TableA‐1–CurrentVersion.........................................................................................................................................................130TableA‐2–CompatibleVersion..................................................................................................................................................130TableB‐1–AllowedAudioFormatsinPDMediaProfile................................................................................................132TableB‐2–HypotheticalRenderModelConstraints(General)...................................................................................133TableB‐3–HypotheticalRenderModelConstraints(Textsubtitle).........................................................................133TableB‐4–AllowedAudioFormatsinSDMediaProfile.................................................................................................136TableB‐5–AllowedEnhancedAudioFormatsinSDMediaProfile...........................................................................136TableB‐6–HypotheticalRenderModelConstraints(Imagesubtitle)......................................................................136TableB‐7–HypotheticalRenderModelConstraints(Imagesubtitle)......................................................................143TableC‐1–PictureFormatsandConstraintsofPDMediaProfilefor24Hz&30HzContent......................155TableC‐2–PictureFormatsandConstraintsofPDMediaProfilefor25HzContent........................................156TableC‐3–PictureFormatsandConstraintsofSDMediaProfilefor24Hz,30Hz&60HzContent.........156TableC‐4–PictureFormatsandConstraintsofSDMediaProfilefor25Hz&50HzContent.......................157
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TableC‐5–PictureFormatsandConstraintsofHDandxHDMediaProfilefor24Hz,30Hz&60HzContent....................................................................................................................................................................................................157TableC‐6–PictureFormatsandConstraintsofHDandxHDMediaProfilefor25Hz&50HzContent....157TableC‐7–PictureFormatsandConstraintsofUHDMediaProfilefor24Hz,30Hz&60HzContent......159TableC‐8–PictureFormatsandConstraintsofUHDMediaProfilefor25Hzand50Hz.................................159TableC‐11–[DStream]GroupAssignment..........................................................................................................................166TableD‐1–AdditionalBoxesoftheDECEFileFormat....................................................................................................169
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Figures Figure1‐1–StructureoftheCommonFileFormat&MediaFormatsSpecification................................................19Figure2‐1–StructureofaDigitalCFFContainer(DCC).......................................................................................................26Figure2‐2–StructureofaDCCHeader.......................................................................................................................................28Figure2‐3–DCCMovieFragmentStructure.............................................................................................................................32Figure2‐4–StructureofaDCCFooter.........................................................................................................................................34Figure4‐1–ExampleofanAVCRandomAccess(RA)Ipicture........................................................................................53Figure4‐2–ExampleofEncodingProcessofLetterboxedSourceContent.................................................................61Figure4‐3–ExampleofDisplayProcessforLetterboxedSourceContent...................................................................63Figure4‐4–ExampleofEncodingProcessforPillarboxedSourceContent.................................................................63Figure4‐5–ExampleofDisplayProcessforPillarboxedSourceContent....................................................................64Figure5‐1–ExampleofAACbit‐stream......................................................................................................................................68Figure5‐2–Non‐AACbit‐streamexample.................................................................................................................................80Figure6‐1–Exampleofsubtitledisplayregionposition..................................................................................................107Figure6‐2–StorageofimagesfollowingtherelatedSMPTETTdocumentinasample.....................................109Figure6‐3–BlockDiagramofHypotheticalRenderModel.............................................................................................110Figure6‐4–TimerelationshipbetweenCFF‐TTdocumentsandtheCFF‐TTtrackISOmediatimeline......113Figure6‐5–BlockDiagramofCFF‐TTImageSubtitleHypotheticalRenderModel..............................................116Figure6‐6–BlockDiagramofCFF‐TTTextSubtitleHypotheticalRenderModel..................................................117Figure6‐7–ExampleofTextSubtitlePresentationCompositorBehavior...............................................................117
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1 Introduction
1.1 Scope
ThisspecificationdefinestheCommonFileFormatandthemediaformatsitsupportsforthestorage,deliveryandplaybackofaudio‐visualcontent.Itincludesacommonmediafileformat,elementarystreamformats,elementarystreamencryptionformatsandmetadatadesignedtooptimizethedistribution,purchase,deliveryfrommultiplepublishers,retailers,andcontentdistributionnetworks;andenableplaybackonmultipleauthorizeddevicesusingmultipleDRMsystemswithinanecosystem.ThisspecificationisintentionallybroadincapabilitysothatMediaProfilesandDeliveryTargetscanbeusedasdefinedinthisSpecification.CombinationsofMediaProfiles,DeliveryTargetsandmandatorycodecs/constraintsarecalled“InteroperabilityPoints”.AdditionalMediaProfiles,DeliveryTargetsandInteroperabilityPointscanbedefinedelsewherewhichenablesotherformatsandecosystemstoadaptuseoftheCommonFileFormattotheirspecificrequirements.
1.2 DocumentOrganization
TheCommonFileFormat(CFF)definesacontainerforaudio‐visualcontentbasedontheISOBaseMediaFileFormat[ISO].Thisspecificationdefinesthesetoftechnologiesandconfigurationsusedtoencodethataudio‐visualcontentforpresentation.Thecorespecificationaddressesthestructure,contentandbaselevelconstraintsthatapplytoallvariationsofCommonFileFormatcontentandhowitistobestoredwithinaDigitalCFFContainer(DCC).Thisspecificationdefineshowvideo,audioandsubtitlecontentintendedforsynchronousplaybackisstoredwithinacompliantfile,aswellashowoneormoreco‐existingdigitalrightsmanagementsystemscanbeusedtoprotectthatcontentcryptographically.MediaProfiles,DeliveryTargetsandInteroperabilityPointsaredefinedintheAnnexesofthisdocument,whichspecifyadditionalrequirementsandconstraintsthatareparticulartoagivenclassofcontent.Overtime,additionalMediaProfiles DeliveryTargetsandInteroperabilityPointsmightbeadded,butsuchadditionswouldnottypicallyrequiremodificationtothecorespecification.
1.3 DocumentNotationandConventions
Thefollowingtermsareusedtospecifyconformanceelementsofthisspecification.TheseareadoptedfromtheISO/IECDirectives,Part2,AnnexH[ISO‐P2H].Formoreinformation,pleaserefertothosedirectives.
SHALLandSHALLNOTindicaterequirementsstrictlytobefollowedinordertoconformtothedocumentandfromwhichnodeviationispermitted.
SHOULDandSHOULDNOTindicatethatamongseveralpossibilitiesoneisrecommendedasparticularlysuitable,withoutmentioningorexcludingothers,orthatacertaincourseofactionispreferredbutnotnecessarilyrequired,orthat(inthenegativeform)acertainpossibilityorcourseofactionisdeprecatedbutnotprohibited.
MAYandNEEDNOTindicateacourseofactionpermissiblewithinthelimitsofthedocument.
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Termsdefinedtohaveaspecificmeaningwithinthisspecificationwillbecapitalized,e.g.“DCCMovieFragment”,andshouldbeinterpretedwiththeirgeneralmeaningifnotcapitalized.
1.4 NormativeReferences
1.4.1 DECE References
[DSystem] SystemSpecification
[DDMP] MediaPackageSpecification[DMeta] ContentMetadataSpecification[DStream] CommonStreamingProtocolSpecificationNote:OtherDECEdocumentscontainrequirementsforanUltraViolet‐compliantimplementation,particularlytheLicenseeImplementationRequirementsasincorporatedintotheComplianceRulesofLicenseeAgreements.
1.4.2 External References
[AAC] ISO/IEC14496‐3:2009,“Informationtechnology—Codingofaudio‐visualobjects—Part3:Audio”with:Amendment1,Amendment2,Amendment3,Amendment4,Corrigendum1,Corrigendum2,Corrigendum3
[AACC] ISO/IEC14496‐26:2010,"Informationtechnology—Codingofaudio‐visualobjects—Part26:Audioconformance”withAmendment2,Corrigendum2,Corrigendum3,Corrigendum4,Corrigendum5,Corrigendum6
[AC4] ETSITS103190V1.1.1(2014‐04),“DigitalAudioCompression(AC‐4)Standard”
[AES] AdvancedEncryptionStandard,FederalInformationProcessingStandardsPublication197,FIPS‐197,http://www.nist.gov
[CENC] ISO/IEC23001‐7:2014,Secondedition,"Informationtechnology‐MPEGsystemstechnologies‐Part7:CommonencryptioninISObasemediafileformatfiles"
[CICP] ISO/IEC23001‐8:2013“Informationtechnology–MPEGsystemstechnologies–Part8:Coding‐independentcodepoints”withAmendment1
[DASH] ISO/IEC23009‐1:2014,Secondedition2014‐05‐15,“Informationtechnology—DynamicadaptivestreamingoverHTTP(DASH)‐Part1:Mediapresentationdescriptionandsegmentformats”
[DTS] ETSITS102114v1.4.1(2012‐09),“DTSCoherentAcoustics;CoreandExtensionswithAdditionalProfiles"
[DV] DolbyLaboratories,“DolbyVisionstreamswithintheISOBaseMediaFileFormat,Version1.0”
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[EAC3] ETSITS102366v.1.3.1(2014‐08),“DigitalAudioCompression(AC‐3,EnhancedAC‐3)Standard”
[H264] ISO/IEC14496‐10:2014,Eighthedition2014‐09‐01,"Informationtechnology‐Codingofaudio‐visualobjects‐Part10:AdvancedVideoCoding"
[H265] ISO/IECFDIS23008‐2,Secondedition,“Informationtechnology‐Highefficiencycodingandmediadeliveryinheterogeneousenvironments‐Part2:Highefficiencyvideocoding”
[IANA‐LANG] IANALanguageSubtagRegistryhttp://www.iana.org/assignments/language‐subtag‐registry
[ISO] ISO/IEC14496‐12:2012,Fourthedition2012‐07‐15,Correctedversion2012‐09‐15,"Informationtechnology‐Codingofaudio‐visualobjects–Part12:ISOBaseMediaFileFormat”withAmendment1,Amendment2,Corrigendum1,Corrigendum2,DCOR3,DCOR4
[ISOVIDEO] ISO/IEC14496‐15:2014,Thirdedition2014‐07‐01,“Informationtechnology‐Codingofaudio‐visualobjects‐Part15:CarriageofNALunitstructuredvideointheISOBaseMediaFileFormat”withDCOR1
[ISOTEXT] ISO/IEC14496‐30:2014,Firstedition2014‐03‐15,“TimedtextandothervisualoverlaysinISObasemediafileformat”withDCOR1
[ISO‐P2H] ISO/IECDirectives,Part2,AnnexHhttp://www.iec.ch/tiss/iec/Directives‐part2‐Ed5.pdf
[MHA] ISO/IECDIS23008‐3,“Informationtechnology–Highefficiencycodingandmediadeliveryinheterogeneousenvironments–Part3:3DAudio”withDAM1“3DAudioProfilesandLevels”andDAM2“3DAudioFileFormatSupport”
[MHP] ETSITS101812V1.3.1,“DigitalVideoBroadcasting(DVB);MultimediaHomePlatform(MHP)Specification1.0.3”,availablefromwww.etsi.org.
[MLP] MeridianLosslessPacking,TechnicalReferenceforFBAandFBBstreams,Version1.0,October2005,DolbyLaboratories,Inc.
[MLPISO] MLP(DolbyTrueHD)streamswithintheISOBaseMediaFileFormat,Version1.0,DolbyLaboratories,Inc.
[MP4] ISO/IEC14496‐14:2003,Firstedition2003‐11‐15,“Informationtechnology‐Codingofaudio‐visualobjects‐Part14:MP4fileformat”with:Amendment1,Corrigendum1
[MP4RA] Registrationauthorityforcode‐pointsintheMPEG‐4family,http://www.mp4ra.org
[MPEG4S] ISO/IEC14496‐1:2010,Fourthedition2010‐06‐01,“Informationtechnology‐Codingofaudio‐visualobjects‐Part1:Systems”with:Amendment1:2010
[MPS] ISO/IEC23003‐1:2007,“Informationtechnology—MPEGaudiotechnologies—Part1:MPEGSurround”withCorrigendum1,Corrigendum2,Corrigendum3,Corrigendum4
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[R601] ITU‐RRecommendationBT.601‐7,“Studioencodingparametersofdigitaltelevisionforstandard4:3andwide‐screen16:9aspectratios”
[R709] ITU‐RRecommendationBT.709‐5,“ParametervaluesfortheHDTVstandardsforproductionandinternationalprogrammeexchange”
[R1700] ITU‐RRecommendationBT.1700,“Characteristicsofcompositevideosignalsforconventionalanaloguetelevisionsystems”
[R1886] ITU‐RRecommendationBT.1886,“Referenceelectro‐opticaltransferfunctionforflatpaneldisplaysusedinHDTVstudioproduction”
[R2020] ITU‐RRecommendationBT.2020‐0,“Parametervaluesfortheultra‐highdefinitiontelevisionsystemsforproductionandinternationalprogrammeexchange”
[RFC2141] “URNSyntax”,R.Moats,May1997,http://www.ietf.org/rfc/rfc2141.txt[RFC4122] Leach,P.,etal,AUniversallyUniqueIdentifier(UUID)URNNamespace,July
2005http://www.ietf.org/rfc/rfc4122.txt[RFC4151] “The'tag'URIScheme”,T.KindbergandS.Hawke,October2005
http://www.ietf.org/rfc/rfc4151.txt[RFC5646] “TagsforIdentifyingLanguages”A.PhilipsandM.Davis,September,2009,
http://www.ietf.org/rfc/rfc5646.txt[RFC6381] “The'Codecs'and'Profiles'Parametersfor"Bucket"MediaTypes”R.Gellens,et
al,August,2011,http://www.ietf.org/rfc/rfc6381.txt[SMPTE428] SMPTE428‐3‐2006,“D‐CinemaDistributionMasterAudioChannelMapping
andChannelLabeling”(c)SMPTE2006[SMPTE‐TT] SMPTEST2052‐1:2010,“TimedTextFormat(SMPTE‐TT)”[SMPTE‐608] SMPTERP2052‐10:2012,“ConversionfromCEA‐608DatatoSMPTE‐TT”[SMPTE‐708] SMPTERP2052‐11,“ConversionfromCEA‐708DatatoSMPTE‐TT”[SMPTE‐2084] SMPTEST2084:2014,“DynamicRangeElectro‐OpticalTransferFunctionof
MasteringReferenceDisplays”[XML] “XMLSchemaPart1:StructuresSecondEdition”,HenryS.Thompson,David
Beech,MurrayMaloney,NoahMendelsohn,W3CRecommendation28October2004,http://www.w3.org/TR/xmlschema‐1/“XMLSchemaPart2:DatatypesSecondEdition”,PaulBironandAshokMalhotra,W3CRecommendation28October2004,http://www.w3.org/TR/xmlschema‐2/
[UNICODE] UNICODE6.0.0,“TheUnicodeStandardVersion6.0”,http://www.unicode.org/versions/Unicode6.0.0/
Note:Readersareencouragedtoinvestigatethemostrecentpublicationsfortheirapplicability.
1.5 InformativeReferences
[ATSC] A/153Part‐7:2009,“ATSC‐MobileDTVStandard,Part7—AVCandSVCVideoSystemCharacteristics”
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[RFC3986] “UniformResourceIdentifier(URI):GenericSyntax”T.Berners‐Lee,R.FieldingandL.Masinter,January2005.http://www.ietf.org/rfc/rfc3986.txt
[W3C‐TT] TimedTextMarkupLanguage(TTML)1.0(SecondEdition),http://www.w3.org/TR/2013/PER‐ttaf1‐dfxp‐20130709/
1.6 Terms,Definitions,andAcronyms
AAC Asdefinedin[AAC],“AdvancedAudioCoding.”AACLC AlowcomplexityaudiotoolusedinAACprofile,definedin[AAC].accessunit,AU Asdefinedin[MPEG4S],“smallestindividuallyaccessibleportionofdata
withinanelementarystreamtowhichuniquetiminginformationcanbeattributed.”
activepicturearea Inavideotrack,theactivepictureareaistherectangularsetofpixelsthatcancontainvideocontentatanypointthroughoutthedurationofthetrack,absentofanyadditionalmattingthatisnotconsideredbythecontentpublishertobeanintegralpartofthevideocontent.
ADIF Asdefinedin[AAC],“AudioDataInterchangeFormat.”ADTS Asdefinedin[AAC],“AudioDataTransportStream.”AES‐CTR AdvancedEncryptionStandard,CounterModeaudiostream Asequenceofsynchronizedaudioframes.audioframe AcomponentofanaudiostreamthatcorrespondstoacertainnumberofPCM
audiosamples.AVC AdvancedVideoCoding[H264].AVClevel AsetofperformanceconstraintsspecifiedinAnnexA.3of[H264],suchas
maximumbitrate,maximumnumberofmacroblocks,maximumdecodingbuffersize,etc.
AVCprofile AsetofencodingtoolsandconstraintsdefinedinAnnexA.2of[H264].BaseLayer maximumsubsetofabitstreamthatisAVCorHEVCcompatible(asdefinedin
[ISOVIDEO])box Asdefinedin[ISO],“object‐orientedbuildingblockdefinedbyauniquetype
identifierandlength.”CBR Asdefinedin[H264],“ConstantBitRate.”CFF CommonFileFormat.(See“CommonFileFormat.”)CFF‐TT “CommonFileFormatTimedText”istheSubtitleformatdefinedbythis
specification.chunk Asdefinedin[ISO],“contiguoussetofsamplesforonetrack.”codedvideosequence(CVS)
Asdefinedin[H264]forAVCvideotracksandasdefinedin[H265]forHEVCvideotracks.
CommonFileFormat(CFF)
ThestandardDECEcontentdeliveryfileformat,encodedinoneoftheapprovedMediaProfilesandpackaged(encodedandencrypted)asdefinedbythisspecification.
containerbox Asdefinedin[ISO],“boxwhosesolepurposeistocontainandgroupasetofrelatedboxes.”
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core InthecaseofDTS,acomponentofanaudioframeconformingto[DTS].CPE Asdefinedin[AAC],anabbreviationforchannel_pair_element().DCCFooter Thecollectionofboxesdefinedbythisspecificationthatmightformtheendof
aDigitalCFFContainer(DCC),definedinSection2.1.4.DCCHeader Thecollectionofboxesdefinedbythisspecificationthatformthebeginningof
aDigitalCFFContainer(DCC),definedinSection2.1.2.DCCMovieFragment
Thecollectionofboxesdefinedbythisspecificationthatformafragmentofamediatrackcontainingonetypeofmedia(i.e.audio,video,subtitles),definedbySection2.1.3.
DECE DigitalEntertainmentContentEcosystemDigitalCFFContainer(DCC)
AninstanceofContentpublishedintheCommonFileFormat.
descriptor Asdefinedin[MPEG4S],“datastructurethatisusedtodescribeparticularaspectsofanelementarystreamoracodedaudio‐visualobject.”
DRM DigitalRightsManagement.EnhancementLayer
layerthatspecifiesapartofascalablebitstreamthatenhancesthevideo(asdefinedin[ISOVIDEO]).
extension InthecaseofDTS,acomponentofanaudioframethatmightormightnotexistinsequencewithotherextensioncomponentsoracorecomponent.
fileformat Adefinitionofhowdataiscodifiedforstorageinaspecifictypeoffile.fragment Asegmentofatrackrepresentingasingle,continuousportionofthetotal
durationofcontent(i.e.video,audio,subtitles)storedwithinthattrack.HD HighDefinition;PictureresolutionofonemillionormorepixelslikeHDTV.HEAAC MPEG‐4HighEfficiencyAACprofile,definedin[AAC].HEVC HighEfficiencyVideoCoding[H265]HEVCtierandlevel
AsetofperformanceconstraintsspecifiedinAnnexA.4of[H265],suchasmaximumbitrate,maximumnumberofmacroblocks,maximumdecodingbuffersize,etc.
HEVCprofile AsetofencodingtoolsandconstraintsdefinedinAnnexA.3of[H265].hinttrack Asdefinedin[ISO],“specialtrackwhichdoesnotcontainmediadata,but
insteadcontainsinstructionsforpackagingoneormoretracksintoastreamingchannel.”
horizontalsub‐samplefactor
Sub‐samplefactorforthehorizontaldimension.See‘sub‐samplefactor’,below.
IMDCT InverseModifiedDiscreteCosineTransform.ISO Inthisspecification“ISO”isusedtorefertotheISOBaseMediaFileformat
definedin[ISO],suchasin“ISOcontainer”or“ISOmediafile”.Itisalsotheacronymfor“InternationalOrganizationforStandardization”.
ISOBaseMediaFile
Fileformatdefinedby[ISO].
Kbps 1x103bitspersecond.LFE LowFrequencyEffects.
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latebinding Thecombinationofseparatelystoredaudio,video,subtitles,metadata,orDRMlicenseswithapreexistingvideofileforplaybackasthoughthelateboundcontentwasincorporatedinthepreexistingvideofile.
luma Asdefinedin[H264],“Anadjectivespecifyingthatasamplearrayorsinglesampleisrepresentingthemonochromesignalrelatedtotheprimarycolours.”
Mbps 1x106bitspersecond.mediaformat Asetoftechnologieswithaspecifiedrangeofconfigurationsusedtoencode
“media”suchasaudio,video,pictures,text,animation,etc.foraudio‐visualpresentation.
MediaProfile RequirementsandconstraintssuchasresolutionandsubtitleformatforcontentintheCommonFileFormat.
MPEG MovingPictureExpertsGroup.MPEG‐4AAC AdvancedAudioCoding,MPEG‐4Profile,definedin[AAC].NALStructuredVideo
NetworkAbstractionLayerStructuredVideo;atechnicalapproachtoformattheVideoCodingLayer(VCL)representationofthevideosuchthatheaderinformationisconveyedinamanorwhichisappropriateforavarietyoftransportlayers.
PD PortableDefinition;intendedforportabledevicessuchascellphonesandportablemediaplayers.
presentation Asdefinedin[ISO],“oneormoremotionsequences,possiblycombinedwithaudio.”
progressivedownload
Theinitiationandcontinuationofplaybackduringafilecopyordownload,beginningoncesufficientfiledatahasbeencopiedbytheplaybackdevice.
PS Asdefinedin[AAC],“ParametricStereo.”sample Asdefinedin[ISO],“allthedataassociatedwithasingletimestamp.”(Notto
beconfusedwithanelementofvideospatialsampling.)sampleaspectratio,SAR
Asdefinedin[H264],“theratiobetweentheintendedhorizontaldistancebetweenthecolumnsandtheintendedverticaldistancebetweentherowsofthelumasamplearrayinaframe.Sampleaspectratioisexpressedash:v,wherehishorizontalwidthandvisverticalheight(inarbitraryunitsofspatialdistance).”
sampledescription
Asdefinedin[ISO],“structurewhichdefinesanddescribestheformatofsomenumberofsamplesinatrack.”
SBR Asdefinedin[AAC],“SpectralBandReplication.”SCE Asdefinedin[AAC],anabbreviationforsingle_channel_element().SD StandardDefinition;usedonawiderangeofdevicesincludinganalog
televisionsub‐samplefactor Avalueusedtodeterminetheconstraintsforchoosingvalidwidthand
heightfieldvaluesforavideotrack,specifiedinSection4.5.1.1.sub‐sampling Invideo,theprocessofencodingpicturedataatalowerresolutionthanthe
originalsourcepicture,thusreducingtheamountofinformationretained.
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substream Inaudio,asequenceofsynchronizedaudioframescomprisingonlyoneofthelogicalcomponentsoftheaudiostream.
track Asdefinedin[ISO],“timedsequenceofrelatedsamples(q.v.)inanISObasemediafile.”
trackfragment Acombinationofmetadataandsampledatathatdefinesasingle,continuousportion(“fragment”)ofthetotaldurationofagiventrack.
UHD UltraHighDefinition;Pictureresolutionupto3840x2160.VBR Asdefinedin[H264],“VariableBitRate.”verticalsub‐samplefactor
Sub‐samplefactorfortheverticaldimension.See‘sub‐samplefactor’,above.
XLL AlogicalelementwithintheDTSelementarystreamcontainingcompressedaudiodatathatwilldecodeintoabit‐exactrepresentationoftheoriginalsignal.
1.7 Architecture(Informative)
ThefollowingsubsectionsdescribethecomponentsofaDigitalCFFContainer(DCC)andhowtheyarecombinedor“layered”tomakeacompletefile.Thespecificationitselfisorganizedinsectionscorrespondingtolayers,alsoincorporatingnormativereferences,whichcombinetoformthecompletespecification.
1.7.1 Media Layers
Thisspecificationcanbethoughtofasacollectionoflayersandcomponents.Thisdocumentandthenormativereferencesitcontainsareorganizedbasedonthoselayers.
Figure1‐1–StructureoftheCommonFileFormat&MediaFormatsSpecification
DECE Common Container & Media Format Specification
Chapter 2. The Common File Format
(Structure, metadata, and descriptors)
Chapter 6. Subtitle Elementary Streams
(Text and image formats, sample storage, and description)
Chapter 3. Encryption of Track Level Data
(Common encryption format, vectors, and keys)
Chapter 4. Video Elementary Streams
(Codec, constraints, sample storage, and description)
Chapter 5. Audio Elementary Streams
(Codecs, constraints, sample storage, and description)
Annexes: Media Profiles
(Profile definitions, requirements, and constraints)
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1.7.2 Common File Format
Section2ofthisspecificationdefinestheCommonFileFormat(CFF)derivedfromtheISOBaseMediaFileFormatand‘iso6’brandspecifiedin[ISO].Thissectionspecifiesrestrictionsandadditionstothefileformatandclarifieshowcontentstreamsandmetadataareorganizedandstored.The‘iso6’brandoftheISOBaseMediaFileFormatconsistsofaspecificcollectionofboxes,whicharethelogicalcontainersdefinedintheISOspecification.Boxescontaindescriptorsthatholdparametersderivedfromthecontainedcontentanditsstructure.OneofthefunctionsofthisspecificationistoequateormaptheparametersdefinedinelementarystreamformatsandothernormativespecificationstodescriptorsinISOboxes,ortoelementarystreamsamplesthatarelogicallycontainedinmediadataboxes.Physically,theISOBaseMediaFileFormatallowsstorageofelementarystreamaccessunitsinanysequenceandanygrouping,intactorsubdividedintopackets,withinorexternallytothefile.AccessunitsdefinedineachelementarystreamaremappedtologicalsamplesintheISOmediafileusingreferencestobytepositionsinsidethefilewheretheaccessunitsarestored.Thelogicalsampleinformationallowsaccessunitstobedecodedandpresentedsynchronouslyonatimeline,regardlessofstorage,aslongastheentireISOmediafileandsamplestoragefilesarerandomlyaccessibleandtherearenoperformanceormemoryconstraints.Inpractice,additionalphysicalstorageconstraintsareusuallyrequiredinordertoensureuninterrupted,synchronousplayback.Toenableusefulfiledeliveryscenarios,suchasprogressivedownload,andtoimproveinteroperabilityandminimizedevicerequirements;theCFFplacesrestrictionsonthephysicalstorageofelementarystreamsandtheiraccessunits.Ratherthanemployanadditionalsystemslayer,theCFFstoresasmallnumberofelementarystreamaccessunitswitheachfragmentoftheISOtrackthatreferencesthoseaccessunitsassamples.BecauselogicalmetadataandphysicalsamplestorageisgroupedtogetherintheCFF,eachsegmentofanISOtrackhasthenecessarymetadataandsampledatafordecryptionanddecodingthatisoptimizedforrandomaccessplaybackandprogressivedownload.
1.7.3 Track Encryption and DRM support
DECEspecifiesastandardencryptionschemeandkeymappingthatcanbeusedwithmultipleDRMsystemscapableofprovidingthenecessarykeymanagementandprotection,contentusagecontrol,anddeviceauthenticationandauthorization.Standardencryptionalgorithmsarespecifiedforregular,opaquesampledata,andforvideodatawithsub‐samplelevelheadersexposedtoenablereformattingofvideostreamswithoutdecryption.The“Scheme”methodspecifiedin[ISO]isrequiredforallencryptedfiles.ThismethodprovidesaccessiblekeyidentificationandmappinginformationthatanauthorizedDRMsystemcanusetocreateDRM‐specificinformation,suchasalicense,thatcanbestoredinareservedareawithinthefile,ordeliveredseparatelyfromthefile.
1.7.3.1 DRMSignalingandLicenseEmbedding
EachDRMsystemthatembedsDRM‐specificinformationinaDCCfiledoessobycreatingaDRM‐specificboxintheMovieBox(‘moov’)asdescribedinSection3.ThisboxcanbeusedtostoreDRM‐specificinformation,suchaslicenseacquisitionobjects,rightsobjects,licensesandotherinformation.ThisinformationisusedbythespecificDRMsystemtoenablecontentdecryptionandplayback.Alternatively,DRM‐specificboxescanbestoredintheMediaPackageasspecifiedby[DDMP].
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1.7.4 VideoElementary Streams
ThisspecificationsupportstheuseofNALStructuredVideoelementarystreamsencodedaccordingtotheAVCcodecspecifiedin[H264]ortheHEVCcodecspecifiedin[H265]andstoredintheCommonFileFormatinaccordancewith[ISOVIDEO],withsomeadditionalrequirementsandconstraints.
1.7.5 Audio Elementary Streams
AwiderangeofaudiocodingtechnologiesaresupportedforinclusionintheCommonFileFormat,includingseveralbasedonMPEG‐4AACaswellasDolby™andDTS™formats.ConsistentwithMPEG‐4architecture,AACelementarystreamsspecifiedinthisformatonlyincluderawaudiosamplesintheelementarybit‐stream.Theserawaudiosamplesaremappedtoaccessunitsattheelementarystreamlevelandsamplesatthecontainerlayer.Othersyntaxelementstypicallyincludedforsynchronization,packetization,decodingparameters,contentformat,etc.aremappedeithertodescriptorsatthecontainerlayer,orareeliminatedbecausetheISOcontaineralreadyprovidescomparablefunctions,suchassampleidentificationandsynchronization.InthecaseofDolbyandDTSformats,completeelementarystreamsnormallyusedbydecodersaremappedtoaccessunitsandstoredassamplesinthecontainer.Someparametersalreadyincludedinthebit‐streamsareduplicatedatthecontainerlevelinaccordancewithISOmediafilerequirements.Duringplayback,thecompleteelementarystream,whichispresentinthestoredsamples,issenttothedecoderforpresentation.Thedecoderusesthein‐banddecodingandstreamstructureparametersspecifiedbyeachcodec.Thesecodecsuseavarietyofdifferentmethodsandstructurestomapandmixchannels,aswellassub‐andextensionstreamstoscalefrom2.0channelsto7.1channelsandenableincreasinglevelsofquality.RatherthantryingtodescribeandenableallthedecodingfeaturesofeachstreamusingISOtracksandsamplegrouplayers,theCommonFileFormatidentifiesonlythemaximumcapabilityofeachstreamatthecontainerlevel(e.g.“7.1channellossless”)andallowsstandarddecodersforthesecodecstodecodeusingthein‐bandinformation(asistypicallydoneintheinstalledbaseofthesedecoders).
1.7.6 Subtitle Elementary Streams
Thisspecificationsupportstheuseofbothimageandtext‐basedsubtitlesintheCommonFileFormatusingtheSMPTETTformatdefinedin[SMPTE‐TT].AnextensionoftheW3CTimedTextMarkupLanguage,subtitlesarestoredasaseriesofSMPTETTdocumentsand,optionally,PNGimages.AsingleDigitalCFFContainercancontainmultiplesubtitletracks,whicharecomposedoffragments,eachcontainingasinglesamplethatmapstoaSMPTETTdocumentandanyimagesitreferences.Thesubtitlesthemselvescanbestoredincharactercodingform(e.g.Unicode)orassub‐pictures,orboth.Subtitletrackscanaddresspurposessuchasnormalcaptions,subtitlesforthedeafandhearingimpaired,descriptivetext,andcommentaries,amongothers.
1.7.7 Media Profiles and Delivery Targets
TheCommonFileFormatdefinesallofthegeneralrequirementsandconstraintsforaconformantDCC.Inaddition,AnnexB.ofthisdocumentdefinesrequirementsforspecificMediaProfilesandAnnexC.ofthisdocumentdefinesrequirementsforspecificDeliveryTargets.
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MediaProfilesnormativelydefinedistinctsubsetsoftheelementarystreamformatsthatcanbestoredwithinaDCCinordertoensureinteroperabilitywithcertainclassesofdevices.Theserestrictionsincludemandatoryandoptionalcodecs,pictureformatrestrictionsandcodecparameterrestrictions,amongothers.Ingeneral,eachMediaProfiledefinesthemaximumsetoftoolsandperformanceparameterscontentispermittedtouseandstillcomplywiththeMediaProfile.However,compliantcontentcanuselessthanthemaximumlimits,unlessotherwisespecified.ThismakesitpossibleforadevicethatdecodesahigherMediaProfileofcontenttoalsobeabletodecodefilesthatconformtolowerMediaProfiles,thoughthereverseisnotnecessarilytrue.DeliveryTargetsnormativelydefineadditionalrestrictionsonelementarystreamformatsandDCCfilestructuretosupportparticulartypesofdeliverymethodssuchasdownloadorstreaming.AconformantDCCwillcomplywiththegeneralrequirementsdefinedinthisspecificationtogetherwithatleastoneMediaProfileandatleastoneDeliveryTarget.ItispossibleforaDCCtosimultaneouslycomplywithmorethanoneDeliveryTarget.Compliantdevicesareexpectedtogracefullyignoremetadataandformatoptionstheydonotsupport.Overtime,additionalMediaProfilesandDeliveryTargetsmightbeaddedinordertosupportnewfeatures,formatsandcapabilities.
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2 TheCommonFileFormat
TheCommonFileFormat(CFF)isbasedonanenhancementoftheISOBaseMediaFileFormatdefinedby[ISO].TheprincipalenhancementstotheISOBaseMediaFileFormataresupportformultipleDRMtechnologiesandseparatestorageofaudio,video,andsubtitlesamplesintrackfragmentstoallowflexibledeliverymethods(includingprogressivedownload)andplayback.
2.1 CommonFileFormat
TheCommonFileFormatisdefinedbythe‘ccff’brand,whichisacodepointontheISOBaseMediaFileFormatdefinedby[ISO].Thebrand‘ccff’requiressupportforallfeaturesofthe‘iso6’brandasdefinedin[ISO].Inaddition,thisspecificationdefinesboxes,requirementsandconstraintsthatarerequiredinadditiontothosedefinedby[ISO];includedareconstraintsonthelayoutofcertaininformationwithinthecontainerinordertoimproveinteroperability,randomaccessplaybackandprogressivedownload.ThefollowingboxesareextensionsfortheCommonFileFormat:
‘coin’:ContentInformationBox(seeSection2.2.2)
‘avcn’:AVCNALUnitStorageBox (not recommended for use – see Section 2.2.3)
‘senc’:SampleEncryptionBox(seeSection2.2.4)
‘trik’:TrickPlayBox(notrecommendedforuse–seeSection2.2.5)Table21‐showstheboxtype,structure,nestinglevelandcross‐referencesfortheCommonFileFormat.ThenestinginTable21indicatescontainment,notnecessarilyorder.DifferencesandextensionstotheISOBaseMediaFileFormatarehighlighted.Unlessotherwiseprohibitedinthisspecification,theDCCandanyboxwithinitcancontainadditionalboxestotheextentpermittedby[ISO].
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Table2‐1‐BoxstructureoftheCommonFileFormat(CFF)NL0 NL1 NL2 NL3 NL4 NL5 FormatReq. Specification Description
ftyp 1 Section2.3.1FileTypeandCompatibility
moov 1 [ISO]8.2.1Containerforfunctionalmetadata
mvhd 1 [ISO]8.2.2 Movieheader coin 1 Section2.2.2 ContentInformationBox
meta 0/1 [ISO]8.11.1Multi‐TrackRequiredMetadata
hdlr 1 Section2.3.3Handlerforcommonfilemetadata
xml 1 Section2.3.4.1XMLforMulti‐TrackRequiredMetadata
iloc 1 [ISO]8.11.3ItemLocation(i.e.forXMLreferencestomandatoryimages,etc.)
idat 0/1 [ISO]8.11.11ContainerforMetadataimagefiles
trak + [ISO]8.3.1 Containerforeachtrack tkhd 1 [ISO]8.3.2 Trackheader edts 0/1 [ISO]8.6.5 EditBox elst 0/1 [ISO]8.6.6 EditListBox mdia 1 [ISO]8.4 TrackMediaInformation mdhd 1 Section2.3.6 MediaHeader
hdlr 1 [ISO]8.4.3Declaresthemediahandlertype
minf 1 [ISO]8.4.4MediaInformationcontainer
vmhd 0/1 Section2.3.7 VideoMediaHeader smhd 0/1 Section2.3.8 SoundMediaHeader sthd 0/1 Section2.3.9 SubtitleMediaHeader dinf 1 [ISO]8.7.1 DataInformationBox
dref 1 Section2.3.10DataReferenceBox,declaressourceofmediadataintrack
stbl 1 [ISO]8.5SampleTableBox,containerforthetime/spacemap
stsd 1 Section2.3.11SampleDescriptions(SeeTable22‐foradditionaldetail.)
stts 1 Section2.3.12 Decoding,TimetoSample stsc 1 Section2.3.16 Sample‐to‐Chunk
stsz/stz2
1 Section2.3.13 SampleSizeBox
stco 1 Section2.3.17 ChunkOffset mvex 1 [ISO]8.8.1 MovieExtendsBox mehd 1 [ISO]8.8.2 MovieExtendsHeader
trex +
(1pertrack)Section2.3.17 TrackExtendsBox
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NL0 NL1 NL2 NL3 NL4 NL5 FormatReq. Specification Description
pssh * [CENC]8.1ProtectionSystemSpecificHeaderBox
free 0/1 [ISO]8.1.2FreeSpaceBoxreservedspaceforDRMinformation
sidx 0/1 Section2.3.21 SegmentIndexBoxemsg * [DASH]5.10.3.3 Eventmessageboxmoof + [ISO]8.8.4 MovieFragment mfhd 1 Section2.3.18 MovieFragmentHeader traf 1 [ISO]8.8.6 TrackFragment tfhd 1 Section2.3.19 TrackFragmentHeader
tfdt 1 [ISO]8.8.12TrackFragmentBaseMediaDecodeTime
trik
0/1forAVCvideowhich
includes(‘avc1’)sampleentries,0forothers
Section2.2.7 TrickPlayBox
trun 1 Section2.3.20 TrackFragmentRunBox
avcn
0/1forAVCvideowhich
includes(‘avc1’)sampleentries,0forothers
Section2.2.2 AVCNALUnitStorageBox
senc 0/1 Section2.2.6 SampleEncryptionBox
saio +ifencrypted,*ifunencrypted
[ISO]8.7.13SampleAuxiliaryInformationOffsetsBox
saiz +ifencrypted,*ifunencrypted
[ISO]8.7.12SampleAuxiliaryInformationSizesBox
sbgp * [ISO]8.9.2 SampletoGroupBox
sgpd * [ISO]8.9.3SampleGroupDescriptionBox
mdat + Section2.3.22MediaDatacontainerformediasamples
meta 0/1 [ISO]8.11.1Multi‐TrackOptionalMetadata
hdlr 0/1 Section2.3.3Handlerforcommonfilemetadata
xml 0/1 Section2.3.4.2XMLforMulti‐TrackOptionalMetadata
iloc 0/1 [ISO]8.11.3ItemLocation(i.e.forXMLreferencestooptionalimages,etc.)
idat 0/1 [ISO]8.11.11ContainerforMetadataimagefiles
mfra 0/1 [ISO]8.8.9MovieFragmentRandomAccess
tfra +
(onepertrack)Section2.3.18
TrackFragmentRandomAccess
mfro 1 [ISO]8.8.11MovieFragmentRandomAccessOffset
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FormatReq.:Numberofboxesrequiredtobepresentinthecontainer,where‘*’means“zeroormore”and‘+’means“oneormore”.Avalueof"0/1"indicatesonlythataboxmightormightnotbepresentbutdoesnotstipulatetheconditionsofitsappearance.
Table2‐2–Additional‘stsd’Detail:ProtectedSampleEntryBoxstructureNL5 NL6 NL7 NL8 FormatReq Source Descriptionstsd 1 Section2.3.11 SampleDescriptionBox
sinf * ISO8.12.1ProtectionSchemeInformationBox
frma 1 ISO8.12.2 OriginalFormatBox schm 1 [ISO]8.12.5 SchemeTypeBox schi 1 [ISO]8.12.6 SchemeInformationBox tenc 1 [CENC]8.2 TrackEncryptionBox
2.1.1 Digital CFF Container Structure
Forthepurposeofthisspecification,theDigitalCFFContainer(DCC)structuredefinedbytheCommonFileFormatisdividedintothreesections:DCCHeader,DCCMovieFragments,andDCCFooter,asshowninFigure21‐.
ADigitalCFFContainerstartswithaDCCHeader,asdefinedinSection2.1.2. OneormoreDCCMovieFragments,asdefinedinSection2.1.3followtheDCCHeader.Otherboxes
MAYexistbetweentheDCCHeaderandthefirstDCCMovieFragment.OtherboxesMAYexistbetweenDCCMovieFragments,aswell.
ADigitalCFFContainerendswithaDCCFooter,asdefinedinSection2.1.4.OtherboxesMAYexistbetweenthelastDCCMovieFragmentandtheDCCFooter.ADCCFooterMAYcontainnoboxes.
Figure2‐1–StructureofaDigitalCFFContainer(DCC)
Digital CFF Container (DCC)
DCC Header …
DCC Footer
DCC Movie Fragment ‐ 1
DCC Movie Fragment ‐ 2
DCC Movie Fragment ‐ n
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2.1.2 DCC Header
TheDCCHeaderdefinesthesetofboxesthatappearatthebeginningofaDigitalCFFContainer(DCC),asshowninFigure22‐.TheboxrequirementsdefinedfortheDCCHeaderSHALLapplytothestartofaDCC,beginningwiththefirstboxintheDCCthroughtothefirstboxofthefirstMovieFragment.Theseboxesaredefinedincompliancewith[ISO]withthefollowingadditionalconstraintsandrequirements:
TheDCCHeaderSHALLstartwithaFileTypeBox(‘ftyp’),asdefinedinSection2.3.1.
TheDCCHeaderSHALLincludeoneMovieBox(‘moov’).
TheMovieBoxSHALLcontainaMovieHeaderBox(‘mvhd’),asdefinedinSection2.3.2.
TheMovieBoxSHALLcontainaContentInformationBox(‘coin’),asdefinedinSection2.2.2.TheContentInformationBox(‘coin’)SHOULDimmediatelyfollowtheMovieHeaderBox(‘mvhd’)intheDCCHeader.
TheMovieBoxMAYcontainMulti‐TrackRequiredMetadataasspecifiedinSection2.1.2.1.Thismetadataprovidescontent,fileandtrackinformationnecessaryforfileidentification,trackselection,andplayback.
TheMovieBoxSHALLcontainmediatracksasspecifiedinSection2.1.2.2,whichdefinestheTrackBox(‘trak’)requirementsfortheCommonFileFormat.
TheMovieBoxSHALLcontainaMovieExtendsBox(‘mvex’),asdefinedinSection8.8.1of[ISO],toindicatethatthecontainerutilizesMovieFragmentBoxes.
TheMovieExtendsBox(‘mvex’)SHALLcontainaMovieExtendsHeaderBox(‘mehd’),asdefinedin[ISO]Section8.8.2,toprovidetheoveralldurationofafragmentedmovie.
TheMovieBox(‘moov’)MAYcontainoneormoreProtectionSystemSpecificHeaderBoxes(‘pssh’),asspecifiedin[CENC]Section8.1.
TheMovieBox(‘moov’)MAYcontainaFreeSpaceBox(‘free’)toprovidereservedspaceforaddingDRM‐specificinformation.IfpresentintheDCCfile,theFreeSpaceBox(‘free’)SHALLbethelastboxintheMovieBox(‘moov’)
TheDCCHeaderMAYcontainaSegmentIndexBox(‘sidx’).Ifpresent,theSegmentIndexBox(‘sidx’)SHALLappearaftertheMovieBox(‘moov’).
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Figure2‐2–StructureofaDCCHeader
2.1.2.1 RequiredMulti‐TrackMetadata
Therequiredmulti‐trackmetadataprovidesmovieandtrackinformation,suchastitle,publisher,runlength,releasedate,tracktypes,languagesupport,etcformulti‐trackDeliveryTargets(seeAnnexC.).Therequiredmulti‐trackmetadataisstoredaccordingtothefollowingdefinition:
AMetaBox(‘meta’),asdefinedin[ISO]Section8.11.1MAYexistintheMovieBox.ThisMetaBoxSHOULDprecedeanyTrackBoxestoenablefasteraccesstothemetadataitcontains.
TheMetaBoxSHALLcontainaHandlerReferenceBox(‘hdlr’)forCommonFileMetadata,asdefinedinSection2.3.3.
TheMetaBoxSHALLcontainanXMLBox(‘xml’)formulti‐trackrequiredmetadata,asdefinedinSection2.3.4.1.
TheMetaBox(‘meta’)SHALLcontainanItemLocationBox(‘iloc’)toenableXMLreferencestoimagesandanyotherbinarydatacontainedinthefile,asdefinedin[ISO]8.11.3.
ImagesandanyotherbinarydatathatarereferencedbyanXMLdocumentintheXMLBox(‘xml’)formulti‐trackrequiredmetadataSHALLbestoredinone‘idat’boxwhichSHOULDfollowallof
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theboxesthe‘meta’boxcontains.EachitemSHALLhaveacorrespondingentryinthe‘iloc’boxdescribedabove,the‘iloc’construction_methodfieldSHALLbesetto‘1’andthe‘iloc’extent_offsetfieldSHALLberelativetothefirstbyteofdata[]inthe‘idat’boxcontainingimagesandanyotherbinarydatathatcanbereferencedbyanXMLdocumentinthe‘xml’box(note:theextent_offsetfieldinthiscaseusesadifferentrelativeoffsetapproachfromotheroffsetfieldsinotherboxes).
2.1.2.2 MediaTracks
Eachtrackofmediacontent(i.e.audio,video,subtitles,etc.)isdescribedbyaTrackBox(‘trak’)inaccordancewith[ISO],withtheadditionofthefollowingconstraints:
EachTrackBox(‘trak’)SHALLcontainaTrackHeaderBox(‘tkhd’),asdefinedinSection2.3.5.
EachTrackBox(‘trak’)MAYcontainanEditBox(‘edts’)asdescribedinSection2.4.
TheEditBoxintheTrackBoxMAYcontainanEditListBox(‘elst’)asdescribedinSection2.4. IfEditListBox(`elst’)isincluded,entry_countSHALLbe1,andtheentrySHALL
havefieldssettothevaluesdescribedinSection2.4. Thetrack_IDassociatedwiththemediatrackSHALLadheretotheassignmentspecifiedinTable
2‐3. EachTrackBox(‘trak’)SHALLNOTreferencemediasamples.
TheMediaBox(‘mdia’)inaTrackBox(‘trak’)SHALLcontainaMediaHeaderBox(‘mdhd’),asdefinedinSection2.3.6.
TheMediaBoxinaTrackBox(‘trak’)SHALLcontainaHandlerReferenceBox(‘hdlr’),asdefinedin[ISO]Section8.4.3.
TheMediaInformationBoxSHALLcontainaheaderboxcorrespondingtothetrack’smediatype,asfollows: Videotracks:VideoMediaHeaderBox(‘vmhd’),asdefinedinSection2.3.8. Audiotracks:SoundMediaHeaderBox(‘smhd’),asdefinedinSection2.3.9. Subtitletracks:SubtitleMediaHeaderBox(‘sthd’),asdefinedinSection2.3.9.
TheDataInformationBoxintheMediaInformationBoxSHALLcontainaDataReferenceBox(‘dref’),asdefinedinSection2.3.10.
TheSampleTableBox(‘stbl’)intheMediaInformationBoxSHALLcontainaSampleDescriptionBox(‘stsd’),asdefinedinSection2.3.11.
Forencryptedtracks,theSampleDescriptionBoxSHALLcontainatleastoneProtectionSchemeInformationBox(‘sinf’),asdefinedinSection2.3.14,toidentifytheencryptiontransformappliedanditsparameters,aswellastodocumenttheoriginal(unencrypted)formatofthemedia.Note:‘sinf’iscontainedinaSampleEntrywithacodingnameof‘enca’or‘encv’whichiscontainedwithintheSampleDescriptionBox(‘stsd’).
TheSampleTableBoxSHALLcontainaDecodingTimetoSampleBox(‘stts’),asdefinedinSection2.3.12.
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TheSampleTableBoxSHALLcontainaSampletoChunkBox(‘stsc’),asspecifiedinSection2.3.16,andaChunkOffsetBox(‘stco’),asdefinedinSection2.3.17,indicatingthatchunksarenotused.
Additionalconstraintsfortracksaredefinedcorrespondingtothetrack’smediatype,asfollows: Videotracks:SeeSection4.2DataStructureforVideoTrack Audiotracks:SeeSection5.2DataStructureforAudioTrack. Subtitletracks:SeeSection6.7DataStructureforCFF‐TTTrack.
Table2‐3–TrackIDAssignmenttrack_IDrange TrackType1‐49 PrimaryVideo50‐99 SecondaryVideo100‐999 MainAudio1,000‐1,999 SecondaryAudio2,000‐9,999 TertiaryAudio10,000‐10,999 MainSubtitle11,000‐11,999 SecondarySubtitle12,000+ Other(e.g.Metadata)
2.1.3 DCC MovieFragment
ADCCMovieFragmentcontainsthemetadataandmediasamplesforalimited,butcontinuoussequenceofhomogenouscontent,suchasaudio,videoorsubtitles,belongingtoasingletrack,asshowninFigure23‐.MultipleDCCMovieFragmentscontainingdifferentmediatypeswithparalleldecodetimesareplacedincloseproximitytooneanotherintheCommonFileFormatinordertofacilitatesynchronousplayback.TheboxrequirementsdefinedforDCCMovieFragmentsSHALLapplytotheDCCaftertheboxrequirementsdefinedfortheDCCHeader.DCCMovieFragmentsSHALLcomplywith[ISO]Section8.8andthefollowingrequirements:
TheDCCMovieFragmentMAYcontainoneormoreEventMessageBoxes(‘emsg’).
TheDCCMovieFragmentSHALLcontainaMovieFragmentBox(‘moof’).TheDCCMovieFragmentSHALLcontainoneormoreMediaDataBoxes(‘mdat’)formediasamples(seeFigure23‐).TheMovieFragmentBox(‘moof’)inaDCCMovieFragmentSHALLcomplywith[ISO]Section8.8.4andthefollowingrequirements:
TheMovieFragmentBoxSHALLcontainasingleTrackFragmentBox(‘traf’)definedin[ISO]Section8.8.6.
AllmediasamplesinaDCCSHALL: bereferencedfromTrackFragmentBoxes(‘traf’)containedinMovieFragmentBoxes
(‘moof’);and onlyutilizeeffectivesampleparameters(sample_index, sample_duration,
sample_size,and sample_flags)infieldsandparameterslocatedineachMovieFragment,eitherintheTrackFragmentHeaderBox(‘tfhd’)orTrackRunBox(‘trun’)(seealsoSection2.3.17);and
onlybeaddressedusingbyteoffsetsrelativetothefirstbyteoftheMovieFragmentBoxes(‘moof’)(seealsoSection2.3.19andSection2.3.20).
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TheTrackFragmentBox(‘traf’)SHALLcontainaTrackFragmentBaseMediaDecodeTimeBox(‘tfdt’),asdefinedin[ISO]Section8.8.12,toprovidedecodestarttimeofthefragment.
ForAVCVideotracksutilizing(‘avc1’)sampleentriesasperSection4.3.1.1,theTrackFragmentBox(‘traf’)MAY: containaTrickPlayBox(‘trik’),asdefinedinSection2.2.7,tofacilitaterandomaccess
andtrickplaymodes(i.e.fastforwardandrewind);and containanAVCNALUnitStorageBox(‘avcn’)asdefinedinSection2.2.2.IfanAVCNAL
UnitStorageBoxispresentinanyAVCVideotrackfragmentintheDCC,oneSHALLbepresentinallAVCvideotrackfragmentsinthatfile.
TheTrackFragmentBox(‘traf’)SHALLcontainexactlyoneTrackFragmentRunBox(‘trun’),asdefinedinSection2.3.20.
ForDCCMovieFragmentswhichcontainencryptedsamples: theTrackFragmentBox(‘traf’)SHALLcontainexactlyoneSampleAuxiliaryInformation
OffsetsBox(‘saio’)withanaux_info_typevalueof"cenc"andexactlyoneSampleAuxiliaryInformationSizesBox(‘saiz’)withanaux_info_typevalueof"cenc",asspecifiedinSection2.2.7;and
theTrackFragmentBox(‘traf’)SHALLcontainexactlyoneSampleEncryptionBox(‘senc’),asspecifiedinSection2.2.4;and
iftheDCCMovieFragmentcontainssampleswithdifferentencryptionkeys,theDCCMovieFragmentsSHALLcontainasamplegroupandsamplegroupdescription(‘seig’)asspecifiedin[CENC].
TheMediaDataBox(‘mdat’)inaDCCMovieFragmentSHALLcomplywithSection2.3.22ofthisSpecification,andthefollowingrequirements: TheMediaDataBoxintheDCCMovieFragmentSHALLcontainallofthemediasamples(i.e.audio,
videoorsubtitles)referredtobytheTrackFragmentBoxthatfallswithinthesameDCCMovieFragment.
ToensureDCCMovieFragmentscontainingdifferentmediatypeswithparalleldecodetimesareplacedincloseproximitytooneanotherinaDCC,DCCMovieFragmentsSHALLbeorderedinsequencebasedonthedecodetimeofthefirstsampleineachDCCMovieFragment(i.e.themoviefragmentstarttime).WhenDCCMovieFragmentssharethesamestarttimes,smallersizefragmentsSHOULDbestoredfirst.
Note:Inthecaseofsubtitletracks,themoviefragmentstarttimemightnotequaltheactualtimeofthefirstappearanceoftextorimagesintheCFF‐TTdocumentstoredinthefirstandonlysampleinDCCMovieFragment.
Additionalconstraintsfortracksaredefinedcorrespondingtothetrack’smediatype,asfollows: Videotracks:SeeSection4.2DataStructureforVideoTrack. Audiotracks:SeeSection5.2DataStructureforAudioTrack.
Subtitletracks:SeeSection6.7DataStructureforCFF‐TTTrack.
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Figure2‐3–DCCMovieFragmentStructure
2.1.4 DCC Footer
TheDCCFootercontainsOptionalMulti‐TrackMetadataandoptionalinformationforsupportingrandomaccessintotheaudio‐visualcontentsofthefile,asshowninFigure24‐.TheboxrequirementsdefinedforDCCFooterSHALLapplytotheDCCafterthelastboxinthelastDCCMovieFragmentthroughtotheendoftheDCC.Theseboxesaredefinedincompliancewith[ISO]withthefollowingadditionalconstraintsandrequirements:
TheDCCFooterMAYcontainaMetaBox(‘meta’),asdefinedin[ISO]Section8.11.1.IftheMetaBox(‘meta’),ispresentintheDCCFooter:
DCC Movie Fragment
Mandatory Box Op onal Box
Movie Data Box (‘mdat’) Movie Fragment samples (all of one type)….
MovieFragmentBox(‘moof’)
Movie Header Box (‘mfhd’)
Track Fragment Box (‘traf’)
Track Fragment Header Box (‘tfhd’)
Event Message Box (‘emsg’)
Track Fragment Base Media Decode Time Box (‘tfdt’)
Trick Play Box (‘trik’) – not recommended, might be present for AVC Video tracks
AVC NAL Unit Storage Box (‘avcn’) – not recommended, might be present for AVC Video tracks
Sample Encryp on Box (‘senc’)
Sample Auxiliary Informa on Offsets Box (‘saio’)
Sample Auxiliary Informa on Sizes Box (‘saiz’)
Sample to Group Box (‘sbgp’)
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TheMetaBox(‘meta’)SHALLcontainaHandlerReferenceBox(‘hdlr’)forCommonFileMetadata,asdefinedinSection2.3.3.
TheHandlerReferenceBoxforCommonFileMetadataSHALLbefollowedbyanXMLBox(‘xml’)forOptionalMetadata,asdefinedinSection2.3.4.2.
TheMetaBox(‘meta’)MAYcontainanItemLocationBox(‘iloc’)toenableXMLreferencestoimagesandanyotherbinarydatacontainedinthefile,asdefinedin[ISO]Section8.11.3.Ifanysuchreferenceexists,thentheItemLocationBoxSHALLexist.
ImagesandanyotherbinarydatareferredtobythecontentsoftheXMLBoxforOptionalMetadataSHALLbestoredinone‘idat’BoxwhichSHOULDfollowalloftheboxestheMetaBoxcontains.EachitemSHALLhaveacorrespondingentryinthe‘iloc’describedaboveandthe‘iloc’construction_methodfieldSHALLbesetto‘1’.
TheDCCFooterMAYcontainaMovieFragmentRandomAccessBox(‘mfra’),asdefinedin[ISO]Section8.8.9.IftheMovieFragmentRandomAccessBox(‘mfra’)ispresentintheDCCFooter: MovieFragmentRandomAccessBox(‘mfra’)SHALLbethelastfile‐levelboxintheDCC
Footer. TheMovieFragmentRandomAccessBox(‘mfra’)SHALLcontainoneTrackFragment
RandomAccessBox(‘tfra’),asdefinedinSection2.3.18,foreachtrackinthefile. ThelastboxcontainedwithintheMovieFragmentRandomAccessBoxSHALLbeaMovie
FragmentRandomAccessOffsetBox(‘mfro’),asdefinedin[ISO]Section8.8.11.
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Figure2‐4–StructureofaDCCFooter
2.2 ExtensionstoISOBaseMediaFileFormat
2.2.1 Standards and Conventions
2.2.1.1 ExtensionBoxRegistration
TheextensionboxesdefinedinSection2.2arenotpartoftheoriginal[ISO]specificationbuthavebeenregisteredwith[MP4RA].
2.2.1.2 Notation
Tobeconsistentwith[ISO],thissectionusesaclass‐basednotationwithinheritance.Theclassesareconsistentlyrepresentedasstructuresinthefileasfollows:Thefieldsofaclassappearinthefilestructureinthesameordertheyarespecified,andallfieldsinaparentclassappearbeforefieldsforderivedclasses.
DCC Footer
Meta Box (‘meta’) for Mul ‐Track Op onal Metadata
Handler Reference Box (‘hdlr’) for Common File Metadata
Mandatory Box Op onal Box
Movie Fragment Random Access Box (‘mfra’)
XML Box (‘xml’) for Op onal Metadata
Track Fragment Random Access Box (‘tfra’) – 1
…
Track Fragment Random Access Box (‘tfra’) – n
Movie Fragment Random Access Offset Box (‘mfro’)
Item Loca on Box (‘iloc’) for XML references to images and other data
Item Data Box (‘idat’) for storage of referenced images and other data
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Forexample,anobjectspecifiedas:aligned(8) class Parent ( unsigned int(32) p1_value, ..., unsigned int(32) pN_value) { unsigned int(32) p1 = p1_value; ... unsigned int(32) pN = pN_value; } aligned(8) class Child ( unsigned int(32) p1_value, ... , unsigned int(32) pN_value, unsigned int(32) c1_value, ... , unsigned int(32) cN_value) extends Parent (p1_value, ..., pN_value) { unsigned int(32) c1 = c1_value; ... unsigned int(32) cN = cN_value; }
Mapsto:aligned(8) struct { unsigned int(32) p1 = p1_value; ... unsigned int(32) pN = pN_value; unsigned int(32) c1 = c1_value; ... unsigned int(32) cN = cN_value; }
Thissectionusesstringsyntaxelements.ThesefieldsSHALLbeencodedasastringofUTF‐8bytesasdefinedin[UNICODE],followedbyasinglenullbyte(0x00).Whenanemptystringvalueisprovided,thefieldSHALLbeencodedasasinglenullbyte(0x00)."Whenaboxcontainsotherboxesaschildren,childboxesalwaysappearafteranyexplicitlyspecifiedfields,andcanappearinanyorder(i.e.siblingboxescanalwaysbere‐orderedwithoutbreakingcompliancetothespecification).
2.2.2 Content Information Box (‘coin’)
BoxType ‘coin’
Container MovieBox(‘moov’)Mandatory YesQuantity OneTheContentInformationBox(‘coin’)containsthefilemetadatanecessarytoidentify,licenseandplaycontentwithinanEcosystem.
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2.2.2.1 2Syntax
aligned(8) class ContentInformationBox extends FullBox(‘coin’, version=1, flags=0) { string mime_subtype_name; string profile-level-idc; string codecs; string protection; string languages; unsigned int(8) brand_entry_count; for( int i=0; i < brand_entry_count; i++) { unsigned int(32) iso_brand; unsigned int(32) version } unsigned int(8) id_entry_count; for( int i=0; i < id_entry_count; i++) { string namespace; string asset_id; } unsigned int(8) id_dependent_entry_count; for( int i=0; i < id_dependent_entry_count; i++) { string dependent_namespace; string dependent_asset_id; } }
2.2.2.2 Semantics
mime_subtype_name‐identifiestheMediaTypeassociatedwiththeDCCandSHALLbesetinaccordancewiththeMediaTypeTemplaterequirementsdefinedinAnnexD.
profile-level-idc‐SHALLbesetinaccordancewiththeprofile-level-idcparameterrequirementsdefinedinAnnexD.
codecs‐SHALLbesetinaccordancewiththecodecsparameterrequirementsdefinedinAnnexD.
protection‐SHALLbesetinaccordancewiththeprotectedparameterrequirementsdefinedinAnnexD.
languages‐SHALLbesetinaccordancewiththelanguagesparameterrequirementsdefinedinAnnexD.
brand_entry_count‐SHALLbesettothenumberofISObrandentriescontainedintheContentInformationBox(‘coin’).
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iso_brand‐SHALLbesettoa[MP4RA]fourcharactercodeassociatedwithanISObrandwithwhichtheDCCiscompatible.OnebrandentrySHALLexistforeachsuchISObrand.AllbrandssignaledintheFileTypeBox('ftyp'),includingbothmajor_brandandcompatible_brandvalues,SHALLbesignaledhere.TheDCCSHALLconformtotherequirementsofanyISObrandsignaledhere.
version‐SHALLbesettotheversionofthespecificationassociatedwiththeISObrandasdefinedbytherelevantspecification.Forbrandsdefinedby[ISO],thefieldvaluewillbesettotheintegerrepresentationof‘4’(torepresent“fourthedition”).
AnyISObrandsdefinedinthisspecificationSHALLbesettotheintegerrepresentationofDMEDIA_VERSION_NOPOINTS(definedinAnnexA.).
id_entry_count–SHALLbesettothenumberofassetIDentriescontainedintheContentInformationBox(‘coin’).
namespace‐SHALLbesettothenamespaceassociatedwiththeassetidentifier.ThenamespaceindicatedSHOULDbeanamespacethatisregisteredorotherwisemanagede.g.for[RFC2141]thenamespacefieldcouldbesetto“urn:<NID>”orfor[RFC4151]thenamespacefieldcouldbe“tag:<taggingEntity>".
asset-id‐SHALLidentifythecontentrenditionwithinthedefinednamespaceincludingthenamespace.Theasset-idfieldSHALLbegloballyunique.
dependent_entry_count–SHALLbesettothenumberofdependentassetIDentriescontainedintheContentInformationBox(‘coin’).IftherearenodependentassetsthenthisfieldSHALLbesetto0.
dependent_namespace‐SHALLbesettothenamespaceassociatedwiththeassetidentifierofadependentasset.ThenamespaceindicatedSHOULDcomplywiththenamespaceregistration/managementrequirementsdefinedforthenamespacefield.
dependent_asset_id‐SHALLidentifythedependentassetwithinthedefinednamespaceincludingthenamespace.ThisfieldisusedtosignalthattheDCCdependsonanotherassettodecodetheDCC.
2.2.3 AVC NAL Unit Storage Box (‘avcn’)
TheAVCNALUnitStorageBox(‘avcn’)SHOULDNOTbeused.Insteadsoleuseofthe(‘avc3’)in‐bandsampleentriesasperSection4.3.1.1isrecommended.TheAVCNALUnitStorageBox(‘avcn’)SHALLNOTappearinAVCVideotrackswhichincludethe(‘avc3’)in‐bandsampleentries(definedinSection4.3.1.1)andSHALLNOTappearinHEVCVideotracks.BoxType ‘avcn’
Container TrackFragmentBox(‘traf’)Mandatory NoQuantity Zero,oroneinanAVCtrackfragmentinafileAnAVCNALUnitStorageBoxSHALLcontainanAVCDecoderConfigurationRecord,asdefinedinsection5.3.3.1of[ISOVIDEO].
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2.2.3.1 Syntax
aligned(8) class AVCNALBox extends Box(‘avcn’) { AVCDecoderConfigurationRecord() AVCConfig; }
2.2.3.2 Semantics
AVCConfig–SHALLcontainsufficientsequenceParameterSetNALUnitandpictureParameterSetNALUnitentriestodescribetheconfigurationsofallsamplesreferencedbythecurrenttrackfragment.
Note:AVCDecoderConfigurationRecordcontainsatableofeachuniqueSequenceParameterSetNALunitandPictureParameterSetNALunitreferencedbyAVCSliceNALUnitscontainedinsamplesinthistrackfragment.Asdefinedin[ISOVIDEO]Section5.2.4.1.2semantics: sequenceParameterSetNALUnitcontainsaSPSNALUnit,asspecifiedin[H264].SPSsshalloccurin
orderofascendingparametersetidentifierwithgapsbeingallowed. pictureParameterSetNALUnitcontainsaPPSNALUnit,asspecifiedin[H264].PPSsshalloccurin
orderofascendingparametersetidentifierwithgapsbeingallowed.
2.2.4 Sample Encryption Box (‘senc’)
BoxType ‘senc’
Container TrackFragmentBox(‘traf’)Mandatory No(Yes,iftrackfragmentisencrypted)Quantity ZerooroneTheSampleEncryptionBoxcontainsthesamplespecificencryptiondata,includingtheinitializationvectorsneededfordecryptionand,optionally,alternativedecryptionparameters.Itisusedwhenthesampledatainthefragmentmightbeencrypted.
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2.2.4.1 Syntax
aligned(8) class SampleEncryptionBox extends FullBox(‘senc’, version=0, flags) { unsigned int(32) sample_count; { unsigned int(IV_size*8) InitializationVector; if (flags & 0x000002) { unsigned int(16) subsample_count; { unsigned int(16) BytesOfClearData; unsigned int(32) BytesOfEncryptedData; } [ subsample_count ] } }[ sample_count ] }
2.2.4.2 Semantics
flagsisinheritedfromtheFullBoxstructure.TheSampleEncryptionBoxcurrentlysupportsthefollowingbitvalues:
0x2–UseSubSampleEncryption IftheUseSubSampleEncryptionflagisset,thenthetrackfragmentthatcontainsthis
SampleEncryptionBoxSHALLusethesub‐sampleencryptionasdescribedinSection3.2.Whenthisflagisset,sub‐samplemappingdatafollowseachInitilizationVector.Thesub‐samplemappingdataconsistsofthenumberofsub‐samplesforeachsample,followedbyanarrayofvaluesdescribingthenumberofbytesofcleardataandthenumberofbytesofencrypteddataforeachsub‐sample.
sample_countisthenumberofencryptedsamplesinthistrackfragment.ThisvalueSHALLbeeitherzero(‘0’)orthetotalnumberofsamplesinthetrackfragment.
InitializationVectorSHALLconformtothedefinitionspecifiedin[CENC]Section9.2.OnlyoneIV_sizeSHALLbeusedwithinafile,orzero(‘0’)whenasampleisunencrypted.SelectionofInitializationVectorvaluesSHOULDfollowtherecommendationsof[CENC]Section9.3. SeeSection3.2forfurtherdetailsonhowencryptionisapplied.
subsample_countSHALLconformtothedefinitionspecifiedin[CENC]Section9.2. BytesOfClearDataSHALLconformtothedefinitionspecifiedin[CENC]Section9.2. BytesOfEncryptedDataSHALLconformtothedefinitionspecifiedin[CENC]Section9.2.
2.2.5 Trick PlayBox (‘trik’)
TheTrickPlayBox(‘trik’)SHOULDNOTbeused.TheTrickPlayBox(‘trik’)SHALLNOTappearinAVCVideotrackswhichutilizethe(‘avc3’)in‐bandsampleentries(definedinSection4.3.1.1)andSHALLNOTappearinHEVCVideotracks.
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BoxType ‘trik’
Container TrackFragmentBox(‘traf’)Mandatory No(MaybeusedforAVCVideotrackswhichinclude(‘avc1’)sampleentriesasperSection
4.3.1.1)Quantity ZerooroneThisboxanswersthreequestionsaboutAVCVideosampledependency:
1. Isthissampleindependentlydecodable(i.e.doesthissampleNOTdependonothers)?2. Cannormal‐speedplaybackbestartedfromthissamplewithfullreconstructionofallsubsequent
picturesinoutputorder?3. Canthissamplebediscardedwithoutinterferingwiththedecodingofaknownsetofother
samples?Whenperformingrandomaccess(i.e.startingnormalplaybackatalocationwithinthetrack),beginningdecodingatsamplesofpicturetype1and2ensuresthatallsubsequentpicturesinoutputorderwillbefullyreconstructable.Note:Picturesoftype3(unconstrainedI‐picture)canbefollowedinoutputorderbysamplesthatreferencepicturespriortotheentrypointindecodingorder,preventingthosepicturesfollowingtheI‐picturefrombeingfullyreconstructedifdecodingbeginsattheunconstrainedI‐picture.Whenperforming“trick”modeplayback,suchasfastforwardorreverse,itispossibletousethedependencylevelinformationtolocateindependentlydecodablesamples(i.e.I‐pictures),aswellaspicturesthatcanbediscardedwithoutinterferingwiththedecodingofsubsetsofpictureswithlowerdependency_levelvalues.IftheTrickPlayBox(‘trik’)ispresentinanAVCVideotrack,itSHALLbepresentintheTrackFragmentBox(‘traf’)forallAVCVideotrackfragments.AsthisboxappearsinaTrackFragmentBox,sample_countSHALLbetakenfromthesample_countinthecorrespondingTrackFragmentRunBox(‘trun’).Allindependentlydecodablesamplesinthevideotrackfragment(i.e.I‐frames)SHALLhaveacorrectpic_typevalueset(value1,2or3);andallothersamplesSHOULDhavethecorrectpic_typeanddependency_levelsetforallpicturescontainedinthevideotrackfragment.
2.2.5.1 Syntax
aligned(8) class TrickPlayBox extends FullBox(‘trik’, version=0, flags=0) { for (i=0; I < sample_count; i++) { unsigned int(2) pic_type; unsigned int(6) dependency_level; } }
2.2.5.2 Semantics
pic_typetakesoneofthefollowingvaluesforAVCvideo: 0–Thetypeofthissampleisunknown. 1–ThissampleisanIDRpicture.
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2–ThissampleisaRandomAccess(RA)I‐picture,asdefinedinSection4.2.6. 3–ThissampleisanunconstrainedI‐picture.
dependency_levelindicatesthelevelofdependencyofthissample,asfollows: 0x00–Thedependencylevelofthissampleisunknown. 0x01to0x3E–Thissampledoesnotdependonsampleswithagreaterdependency_level
valuesthanthisone. 0x3F–Reserved.
2.2.6 Clear Samples within an Encrypted Track
“Encryptedtracks”MAYcontainunencryptedsamples.An“Encryptedtrack”isatrackwhoseSampleEntryhasthecodingnameofeither‘encv’or‘enca’andhasTrackEncryptionBox(‘tenc’)withIsEncryptedvalueof0x1.IfsamplesinaDCCMovieFragmentforan“encryptedtrack”arenotencrypted,theTrackFragmentBox(‘traf’)oftheMovieFragmentBox(‘moof’)inthatDCCMovieFragmentSHALLcontainaSampletoGroupBox(‘sbgp’)andaSampleGroupDescriptionBox(‘sgpd’).TheentryintheSampletoGroupBox(‘sbgp’)describingtheunencryptedsamplesSHALLhaveagroup_description_indexthatpointstoaCencSampleEncryptionInformationVideoGroupEntryorCencSampleEncryptionInformationAudioGroupEntrystructurethathasanIsEncrypted of‘0x0’(Notencrypted)andaKIDofzero(16bytesof‘0’).TheCencSampleEncryptionInformationVideoGroupEntryorCencSampleEncryptionInformationAudioGroupEntryreferencedbytheSampletoGroupBox(‘sbgp’)inaTrackFragmentBox(‘traf’)SHALLbepresentatthereferencedgroupdescriptionindexlocationintheSampleGroupDescriptionBox(‘sgpd’)inthesameTrackFragmentBox(‘traf’).Note:Thegroupdescriptionindexesstartat0x10001asspecifiedin[ISO].TrackfragmentsSHALLNOThaveamixofencryptedandunencryptedsamples.Forclarity,thisdoesnotconstrainsubsampleencryptionasdefinedin[CENC]forNALStructuredVideotracks.Ifatrackfragmentisnotencrypted,thentheSampleEncryptionBox(‘senc’),andrelatedSampleAuxiliaryInformationOffsetsBox(‘saio’)andSampleAuxiliaryInformationSizesBox(‘saiz’)SHALLbeomitted.
2.2.7 Storing Sample Auxiliary Information in a Sample Encryption Box
Forencryptedtrackfragments,theTrackFragmentBox(‘traf’)SHALLcontainaSampleAuxiliaryInformationOffsetsBox(‘saio’)withanaux_info_typevalueof"cenc"asdefinedin[CENC]Section7toprovidesample‐specificencryptiondata.ThisSampleAuxiliaryInformationOffsetsBox(‘saio’)isconstrainedasfollows:
TheoffsetfieldSHALLpointtothefirstbyteofthefirstinitializationvectorintheSampleEncryptionBox('senc');and
Theentry_countfieldSHALLbe1asthedataintheSampleEncryptionBox(‘senc’)iscontiguousforallofthesamplesinthemoviefragment(theCencSampleAuxiliaryDataFormatstructurehasthesameformatasthedataintheSampleEncryptionBox('senc'),bydesign);and
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theoffsetfieldoftheentrySHALLbecalculatedasthedifferencebetweenthefirstbyteofthecontainingMovieFragmentBox(‘moof’)andthefirstbyteofthefirstInitializationVectorintheSampleEncryptionBox(assumingmoviefragmentrelativeaddressingwherenobasedataoffsetisprovidedinthetrackfragmentheader).
ThesizeofthissampleauxiliarydataSHALLbespecifiedinaSampleAuxiliaryInformationSizesBox(‘saiz’)withanaux_info_typevalueof"cenc",asdefinedin[CENC]Section7.ThisSampleAuxiliaryInformationSizesBox(‘saiz’)isconstrainedasfollows:
thesample_countfieldSHALLmatchthesample_countintheSampleEncryptionBox('senc');and
thedefault_sample_info_sizeSHALLbezero(‘0’)ifthesizeoftheper‐sampleinformationisnotthesameforallofthesamplesintheSampleEncryptionBox('senc').Notethatsampleencryptioninformation,suchasinitializationvectors,referencedbytheSampleAuxiliaryInformationOffsetsBox(‘saio’)takesprecedenceoversampleencryptioninformationstoredintheSampleEncryptionBox(‘senc’)‐thisspecificationdefinesstorageinaSampleEncryptionBox(‘senc’)ineachmoviefragment,butoperationssuchasdefragmentationthatcanoccurinplayersorothersystemsrelyonSampleAuxiliaryInformationOffsetsBox(‘saio’)offsetpointersthatcanrefertoanystoragelocation.
2.3 ConstraintsonISOBaseMediaFileFormatBoxes
2.3.1 File TypeBox (‘ftyp’)
FilesconformingtotheCommonFileFormatSHALLincludeaFileTypeBox(‘ftyp’)asspecifiedby[ISO]Section4.3withthefollowingconstraints: The‘ccff’ISObrandSHALLbesetasacompatible_brandintheFileTypeBox(‘ftyp’).Note:
Signalingofthe‘ccff’brandindicatesthatthefilefullycomplieswithSections1throughto6ofthisspecification. Ifthemajor_brandfieldissetto‘ccff’,theminor_versionfieldSHALLbesettothe
integerrepresentationofDMEDIA_VERSION_NOPOINTS(definedinAnnexA.). Note:compatible_brandsmightincludeadditionalbrandsthatthefileconformstosuchas
‘iso6’.
2.3.2 Movie Header Box (‘mvhd’)
TheMovieHeaderBoxinaDCCSHALLconformto[ISO]Section8.2.2withthefollowingadditionalconstraints:
ThevalueofthedurationfieldSHALLbesettoavalueofzero(‘0’). ThefollowingfieldsSHALLbesettotheirdefaultvaluesasdefinedin[ISO]:
rate,volumeandmatrix.
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2.3.3 Handler Reference Box (‘hdlr’) for Common File Metadata
TheHandlerReferenceBox(‘hdlr’)forCommonFileMetadataSHALLconformto[ISO]Section8.4.3withthefollowingadditionalconstraints:
Thevalueofthehandler_typefieldSHALLbe‘cfmd’,indicatingtheCommonFileMetadatahandlerforparsingrequiredandoptionalmetadatadefinedinSection4of[DMeta].
ForMulti‐TrackRequiredMetadata,thevalueofthenamefieldSHOULDbe“RequiredMetadata”. ForMulti‐TrackOptionalMetadata,thevalueofthenamefieldSHOULDbe“OptionalMetadata”.
2.3.4 XML Box (‘xml’) for CommonFile Metadata
TwotypesofXMLBoxesaredefinedinthisspecification.OnecontainsMulti‐TrackRequiredMetadata,andtheothercontainsMulti‐TrackOptionalMetadata.OthertypesofXMLBoxesnotdefinedhereMAYexistwithinaDCC.
2.3.4.1 XMLBox(‘xml’)forMulti‐TrackRequiredMetadata
TheXMLBoxforMulti‐TrackRequiredMetadataSHALLconformto[ISO]Section8.11.2withthefollowingadditionalconstraints:
ThexmlfieldSHALLcontainawell‐formedXMLdocumentwithcontentsthatconformtoSection4.1of[DMeta].
2.3.4.2 XMLBox(‘xml’)forMulti‐TrackOptionalMetadata
TheXMLBoxforMulti‐TrackOptionalMetadataSHALLconformto[ISO]Section8.11.2withthefollowingadditionalconstraints:
ThexmlfieldSHALLcontainawell‐formedXMLdocumentwithcontentsthatconformtoSection4.2of[DMeta].
2.3.5 Track Header Box (‘tkhd’)
TrackHeaderBoxesinaDCCSHALLconformto[ISO]Section8.3.1withthefollowingadditionalconstraints:
ThevalueofthedurationfieldSHALLbesettoavalueofzero(‘0’). ThefollowingfieldsSHALLbesettotheirdefaultvaluesasdefinedin[ISO]:
matrix ThefollowingfieldSHALLbesettoitsdefaultvalueasdefinedin[ISO],unlessspecifiedotherwise
inthisspecification: layer Note:Section6.7.1.1specifiesthelayerfieldvalueforsubtitletracks.
Thewidthandheightfieldsforanon‐visualtrack(i.e.audio)SHALLbe0. ThewidthandheightfieldsforavisualtrackSHALLspecifythetrack’svisualpresentationsizeas
fixed‐point16.16valuesexpressedinsquarepixelsafterdecodercroppingparametershavebeenapplied,withoutcroppingofvideosamplesin“overscan”regionsoftheimageandafterscalinghas
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beenappliedtocompensatefordifferencesinvideosamplesizesandshapes;e.g.NTSCandPALnon‐squarevideosamples,andsub‐samplingofhorizontalorverticaldimensions.Trackvideodataisnormalizedtothesedimensions(logically)beforeanytransformationordisplacementcausedbyacompositionsystemoradaptationtoaparticularphysicaldisplaysystem.Trackandmoviematrices,ifused,alsooperateinthisuniformlyscaledspace. Note:Section4.2.1specifiesadditionalconstraintsforVideotracksandSection6.7.2
specifiesadditionalconstraintsforSubtitletracks.
2.3.6 Media Header Box (‘mdhd’)
MediaHeaderBoxesinaDCCSHALLconformto[ISO]Section8.4.2withthefollowingadditionalconstraints:
ThevalueofthedurationfieldSHALLbesettoavalueofzero(‘0’);Note:ThedurationfieldintheMediaHeaderBox(‘mdhd’)appliestotheTrackBox(‘trak’),whichcontainsnomediasamplesinDCCs.Thedurationofanentirefragmentedmoviecanoptionallybestoredinthefragment_durationfieldoftheMovieExtendsHeaderBox(‘mehd’),whichisequaltothesumofalltrackfragmentdurationsinthelongesttrackinthemovie.
ThetimescalefieldSHOULDcontainavaluethatisexactlydivisiblebysampleduration(thisallowsafixeddefaultsampledurationratherthanatablewithdifferentvaluespersample,whichwouldberequiredifthetimebasecausesroundingorsamplingerrorsonfixeddurationaudioandvideosamples);
ThelanguagefieldSHOULDrepresenttheoriginalreleaselanguageofthecontent.Note:RequiredMetadata(asdefinedinSection2.1.2.1)providesnormativelanguagedefinitionsforCFF.
2.3.7 VideoMedia Header (‘vmhd’)
VideoMediaHeaderBoxesinaDCCSHALLconformto[ISO]Section8.4.5withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLbesettotheirdefaultvaluesasdefinedin[ISO]Section8.4.5: version=0 graphicsmode=0 opcolor={0, 0, 0}
2.3.8 Sound Media Header (‘smhd’)
SoundMediaHeaderBoxesinaDCCSHALLconformto[ISO]Section8.4.5withthefollowingadditionalconstraints:
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ThefollowingfieldsSHALLbesettotheirdefaultvaluesasdefinedin[ISO]Section8.4.5: version=0
2.3.9 Subtitle Media Header Box (‘sthd’)
SubtitleMediaHeaderBoxesinaDCCSHALLconformto[ISO]Section8.4.5withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLbesettotheirdefaultvaluesasdefinedin[ISO]Section8.4.5: version=0
2.3.10 Data Reference Box (‘dref’)
DataReferenceBoxesinaDCCSHALLconformto[ISO]Section8.7.2withthefollowingadditionalconstraints:
TheDataReferenceBox(‘dref’)SHALLcontainasingleentrywiththeentry_flagsfieldsetto0x000001(whichmeansthatthemediadataisinthesamefileastheMovieBoxcontainingthisdatareference).
2.3.11 Sample Description Box (‘stsd’)
SampleDescriptionBoxesinaDCCSHALLconformtoversion0asdefinedin[ISO]Section8.5.2withthefollowingadditionalconstraints:
Sampleentriesforencryptedtracks(thosecontaininganyencryptedsampledata)SHALLencapsulatetheexistingsampleentrywithaProtectionSchemeInformationBox(‘sinf’)thatconformstoSection2.3.14.
Forvideotracks,avisualsampleentrySHALLbeused.DesignrulesarespecifiedinSection4.2.2. Foraudiotracks,anaudioSampleentrySHALLbeused.DesignrulesarespecifiedinSection5.2.6. ForsubtitletracksasubtitlesampleentrySHALLbeused.DesignrulesarespecifiedinSection
6.7.1.5.
2.3.12 ProtectionScheme Information Box (‘sinf’)
TheDCCSHALLuseCommonEncryptionasdefinedin[CENC]andfollowSchemeSignalingasdefinedin[CENC]Section4.TheDCCMAYincludemorethanone'sinf'box.
2.3.13 Decoding Time toSample Box (‘stts’)
DecodingTimetoSampleBoxesinaDCCSHALLconformto[ISO]Section8.6.1.2withthefollowingadditionalconstraints:
Theentry_countfieldSHOULDhaveavalueofzero(‘0’).
2.3.14 Sample to Chunk Box(‘stsc’)
SampletoChunkBoxesinaDCCSHALLconformto[ISO]Section8.7.4withthefollowingadditionalconstraints:
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Theentry_countfieldSHALLbesettoavalueofzero(‘0’).
2.3.15 Sample Size Boxes (‘stsz’ or‘stz2’)
Boththesample_sizeandsample_countfieldsofthe‘stsz’boxSHALLbesettozero(‘0’).Thesample_countfieldofthe‘stz2’boxSHALLbesettozero(‘0’).TheactualsamplesizeinformationcanbefoundintheTrackFragmentRunBox(‘trun’) forthetrack.Note:thisisbecausetheMovieBox(‘moov’)containsnomediasamples.
2.3.16 Chunk Offset Box (‘stco’)
ChunkOffsetBoxesinaDCCSHALLconformto[ISO]Section8.7.5withthefollowingadditionalconstraints:
Theentry_countfieldSHALLbesettoavalueofzero(‘0’).
2.3.17 Track Extends Box (‘trex’)
TrackExtendsBoxes(‘trex’)inaDCCSHALLconformto[ISO]Section8.8.3.DCCsSHALLNOTrelyondefaultflagsorparametersintheTrackExtendsBox(‘trex’)locatedintheMovieBox(‘moov’),including:
default_sample_description_index
default_sample_duration
default_sample_size
default_sample_flagsNote:DefaultsampleparametersintheTrackExtendsBox(‘trex’)arestoredintheDCCHeader,andmaynotbeavailableforeachMediaSegmentduringdecoding.ValuesintheTrackFragmentRunBox(‘trun’)overridedefaultvaluesintheTrackFragmentHeaderBox(‘tfhd’)whichoverridedefaultvaluesintheTrackExtendsBox(‘trex’);sodefaultvaluescanbesetintheTrackExtendsBox(‘trex’)aslongastheyareduplicatedoroverriddenbyvaluesintheTrackFragmentHeaderBox(‘tfhd’)orTrackFragmentRunBox(‘trun’)sothattheeffectivevaluesarestoredineachmoviefragmente.g.adefaultdurationcanbesetforaudioorvideosamplesintheTrackExtendsBox(‘trex’)andeveryTrackFragmentHeaderBox(‘tfhd’),andthatdurationcanbeinheritedbydefaultbyallsamplesinTrackFragmentRunBoxes(‘trun’).
2.3.18 Movie Fragment Header Box (‘mfhd’)
MovieFragmentHeaderBoxes(‘mfhd’)inaDCCSHALLconformto[ISO]Section8.8.5withthefollowingadditionalconstraints:
MovieFragmentHeaderBoxes(‘mfhd’)SHALLcontainsequence_numbervaluesthataresequentiallynumberedstartingwiththenumber1andincrementingby+1,sequencedbymoviefragmentstorageandpresentationorder.
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2.3.19 Track Fragment Header Box (‘tfhd’)
TrackFragmentHeaderBoxes(‘tfhd’)inaDCCSHALLconformto[ISO]Section8.8.7withthefollowingadditionalconstraints:
thebase-data-offset-presentflag(inthetf_flagsfield)SHALLbesettofalseinordertoindicatethatmediasamplesareaddressedusingbyteoffsetsrelativetothefirstbyteoftheMovieFragmentBox(‘moof’);and
thedefault-base-is-moofflag(inthetf_flagsfield)SHALLbesettotrueinordertoindicatethatthedata_offsetfieldintheTrackFragmentRunBox(‘trun’)isalwayscalculatedrelativetothefirstbyteoftheenclosingMovieFragmentBox(‘moof’).
2.3.20 Track Fragment Run Box (‘trun’)
TrackFragmentRunBoxes(‘trun’)inaDCCSHALLconformto[ISO]Section8.8.8withthefollowingadditionalconstraints:
theversionfieldSHALLbesetto‘1’;and
thedata-offset-presentflag(inthetf_flagsfield)SHALLbesettotrueinordertoindicatethatthedata_offsetfieldispresentandcontainsthebyteoffsetfromthestartofthisfragment’sMovieFragmentBox(‘moof’)tothefirstsampleofmediadatainthefollowingMediaDataBox(‘mdat’).
2.3.21 Segment Index Box (‘sidx’)
TheSegmentIndexBox(‘sidx’)SHALLcomplywith[ISO]Section8.16.3withthefollowingadditionalconstraints:
ThetimescalefieldSHALLhavethesamevalueasthetimescalefieldintheMediaHeaderBox(‘mdhd’)withinthesametrack;and
➢thereference_IDfieldSHALLbesettothetrack_IDoftheISOMediatrackasdefinedintheTrackHeaderBox(‘tkhd’).
2.3.22 Media Data Box (‘mdat’)
EachDCCMovieFragmentcontainsaninstanceofaMediaDataboxformediasamples.ThedefinitionofthisboxcomplieswiththeMediaDataBox(‘mdat’)definitionin[ISO]Section8.1.1withthefollowingadditionalconstraints:
EachinstanceofthisboxSHALLcontainonlymediasamplesforasingletrackfragmentofmediacontent(i.e.audio,video,orsubtitlesfromonetrack).Inotherwords,allsampleswithinaninstanceofthisboxbelongtothesameDCCMovieFragment.
2.3.23 Track Fragment Random Access Box (‘tfra’)
TrackFragmentRandomAccessBoxesinaDCCSHALLconformto[ISO]Section8.8.10withthefollowingadditionalconstraint:
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AtleastoneentrySHALLexistforeachfragmentinthetrackthatreferstothefirstrandomaccessiblesampleinthefragment.
2.4 Inter‐trackSynchronization
Therearetwotechniquesavailabletoshiftdecodingandcompositiontimelinestoguaranteeaccurateinter‐tracksynchronization:1)usenegativecompositionoffsets;or2)useeditlists.Thesetechniquesareusedwhenthereisreorderingofvideoframes,and/ormisalignmentofinitialvideoandaudioframeboundariestoachieveaccurateinter‐tracksynchronization.Acombinationofthesetechniquescanbeused;negativecompositionoffsetstoadjustforreorderingofvideoframeswithoutintroducingpresentationdelay,andeditlistsforanaudiotracktoadjustforinitialaudiosyncframeboundarymisalignment.Thissectiondescribeshowtousethesetechniques.
2.4.1 Mapping media timeline to presentationtimeline
NegativecompositionoffsetsintheTrackRunBox(‘trun’)SHALLbeusedtoadjustthecompositiontimeofthefirstpresentedvideosampleinavideotrackfragmenttoequalthedecodetimeofthefirstdecodedsampleinthatfragment.CompositionoffsetsinsubsequentsamplesSHALLreordersamplesforcontinuouspresentationattheintendedframerate.Note:Thisresultsinvideotracksbeingsynchronizedtomoviepresentationtime,andtoaudioandsubtitletrackswhosesamplepresentationtimesalsoequaltheirdecodetimes.TheEditListBox(‘elst’)SHALLNOTbeusedtomapthespecifiedMedia‐Timeinthemediatimelinetothestartofthepresentationtimelineinvideotracks.
2.4.2 Adjusting audiosyncframe boundary misalignments
Toadjustformisalignmentbetweenthestartofthefirstaudiosyncframeboundaryandthestartofthemovietimeline,aneditlisttimelinemappingeditentryMAYbeusedtodefineaninitialoffsetintheaudiotrack.Thismightbenecessarytocorrectforanon‐zeropresentationtimeofthefirstaudiosyncframe‐forexampleaudioencodingbeganearlierandwasthentrimmedtothenearestsyncframetoalignwiththestartofvideopresentation.Unlessaudioandvideoencodersstartsimultaneously,audioandvideoframeboundarieswillusuallynotbealignedbecausetheyhavedifferentdurations.AudiotrackfragmentsSHALLstartwiththefirstsyncframethatoverlapsorstartsatpresentationtimezero.Whenthereisasyncframeboundarymismatchandaccurateinter‐tracksynchronizationisrequired:
Theaudiotimelinemappingeditentryvaluesaresetasfollows:Segment-duration=0Media-Time=initialoffsetMedia-Rate=1
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3 EncryptionofTrackLevelData
3.1 MultipleDRMSupport(Informative)
SupportformultipleDRMsystemsintheCommonFileFormatisaccomplishedbyusingtheCommonEncryptionmechanismdefinedin[CENC],alongwithadditionalmethodsforstoringDRM‐specificinformation.ThestandardencryptionmethodutilizesAES128‐bitinCountermode(AES‐CTR)asdefinedin[AES].EncryptionmetadataisdescribedusingtrackleveldefaultsintheTrackEncryptionBox(‘tenc’)thatcanbeoverriddenusingsamplegroups.ProtectedtracksaresignaledusingtheSchememethodspecifiedin[ISO].DRM‐specificinformationcanbestoredinthenewProtectionSystemSpecificHeaderBox(‘pssh’).Initializationvectorsarespecifiedonasamplebasistofacilitatefeaturessuchasfastforwardandreverseplayback.KeyIdentifiers(KID)areusedtoindicatewhatencryptionkeywasusedtoencryptthesamplesineachtrackorfragment.EachoftheMediaProfiles(seeAnnexB.)defineconstraintsonthenumberandselectionofencryptionkeysforeachtrack,butanyfragmentinanencryptedtrackcanbeunencryptedifidentifiedassuchbytheIsEncrypted fieldinthefragmentmetadata.Bystandardizingtheencryptionalgorithminthisway,thesamefilecanbeusedbymultipleDRMsystems,andmultipleDRMsystemscangrantaccesstothesamefiletherebyenablingplaybackofasinglemediafileonmultipleDRMsystems.ThedifferencesbetweenDRMsystemsarereducedtohowtheyacquirethedecryptionkey,andhowtheyrepresenttheusagerightsassociatedwiththefile.ThedataobjectsusedbytheDRM‐specificmethodsforretrievingthedecryptionkeyandrightsobjectorlicenseassociatedwiththefilearestoredintheProtectionSystemSpecificHeaderBox(‘pssh’)asspecifiedin[CENC].PlayersarerequiredtobecapableofparsingthefilesthatincludethisDRMsignalingmechanism.AnynumberofProtectionSystemSpecificHeaderBoxes(‘pssh’)canbecontainedintheMovieBox(‘moov’)orintheMediaPackagespecifiedby[DDMP];eachboxcorrespondingtoadifferentDRMsystem.TheboxesandDRMsystemareidentifiedbyaSystemID.ThedataobjectsusedforretrievingthedecryptionkeyandrightsobjectarestoredinanopaquedataobjectofvariablesizewithintheProtectionSystemSpecificHeaderBox.ADCCHeaderrequiresthataFreeSpaceBox(‘free’),ifpresent,bethelastboxintheMovieBox,followinganyProtectionSystemSpecificHeaderBoxes(‘pssh’)thatitcancontain.WhenDRM‐specificinformationisaddedintoaDCCitisrequiredthatthetotalsizeoftheDRM‐specificinformationandFreeSpaceBoxremainsconstant,inordertoavoidchangingthefilesizeandinvalidatingbyteoffsetpointersusedthroughoutthemediafile.Decryptionisinitiatedwhenadevicedeterminesthatthefilehasbeenprotectedbyastreamtypeof‘encv’(encryptedvideo)or‘enca’(encryptedaudio)–thisispartoftheISOstandard.TheISOparserexaminestheSchemeInformationboxwithintheProtectionSchemeInformationBoxanddeterminesthatthetrackisencryptedviatheDECEscheme.TheparserthenlooksforaProtectionSystemSpecificHeaderBox(‘pssh’)thatcorrespondstoaDRM,whichitsupports.AdeviceusestheopaquedataintheselectedProtectionSystemSpecificHeaderBoxtoaccomplisheverythingrequiredbytheparticularDRMsystemtoobtainadecryptionkey,obtainrightsobjectsorlicenses,authenticatethecontent,andauthorizetheplaybacksystem.UsingthekeyitobtainsandakeyidentifierintheTrackEncryptionBox(‘tenc’)orasamplegroupdescriptionwithgroupingtypeof‘seig’,whichissharedbyalltheDRMsystems,itcanthendecryptaudioandvideosamples.
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3.2 TrackEncryption
EncryptedtrackleveldatainaDCCSHALLusetheencryptionschemedefinedin[CENC]Section9.EncryptedNALStructuredVideotracksSHALLfollowtheschemeoutlinedin[CENC]Section9.6.2,whichdefinesaNALunitbasedencryptionschemetoallowaccesstoNALsandunencryptedNALheadersinanencryptedNALStructuredVideoelementarystream.AllothertypesoftracksSHALLfollowtheschemeoutlinedin[CENC]Section9.5,whichdefinesasimplesample‐basedencryptionscheme.ThefollowingadditionalconstraintsSHALLbeappliedtoallencryptedtracks:
AllkeyidentifiervaluesSHALLbeaUUIDconformingto[RFC4122]andbinaryencodedintheKIDfieldaccordingto[RFC4122]section4.1.2.
CorrespondenceofkeysandKIDvaluesSHOULDbe1:1;i.e.iftwotrackshavethesamekey,thentheywillhavethesameKIDvalue,andviceversa.
ThefollowingadditionalconstraintsSHALLbeappliedtotheencryptionofNALStructuredVideotracks: TheBytesOfEncryptedDatainallNALUnitsubsamplesSHALLbeeitherzero(‘0’)oramultiple
of16;and IfaNALUnitcontainsfewerthan112bytes,theentireNALUnitSHALLbeunencrypted;and
IfaNALUnitcontains112bytesormore,thefirst96ormorebytesofeachNALUnitSHALLbeunencrypted.
Note:thisbyterangeincludestheNALlengthandnal_unit_typefieldsinaNALUnit.
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4 VideoElementaryStreams
4.1 Introduction
ThischapterdescribesthevideotrackinrelationtotheISOBaseMediaFileandtheconstraintsoneachvideoformat.ThemappingofvideosequencesandparameterstosamplesanddescriptorsinaDCCisdefinedinSection4.2,specifyingwhichmethodsallowedin[ISO]and[ISOVIDEO]SHALLbeused.
4.2 DataStructureforVideoTrack
CommonFileFormatforvideotrackSHALLcomplywith[ISO]and[ISOVIDEO].Inthissection,theoperationalrulesforboxesandtheircontentsofCommonFileFormatforvideotrackaredescribed.
4.2.1 Track Header Box (‘tkhd’)
Forvideotracks,thefieldsoftheTrackHeaderBox(‘tkhd’)SHALLbesettothevaluesspecifiedbelow.Therearesome“template”fieldsdeclaredtouse;see[ISO].
flags=0x000007,exceptforthecasewherethetrackbelongstoanalternategroup widthandheightmustcorrespondascloselyaspossibletotheactivepictureareaofthevideo
contentandSHALLbesettotheNormalizedDisplayHeightandWidthoftheencodedvideo. TheNormalizedDisplayHeightSHALLbetheverticalsamplecountaftercroppingof
encodedlinepairstotheactiveimageheightindicatedbycroppingparameters. TheNormalizedDisplayWidthSHALLbetheequivalentnumberofhorizontalsquarepixels
aftercroppingandsampleaspectratioscalingtotheactiveimagewidthindicatedbycroppingparameters.
Note:NormalizedDisplaySizeindicatesthevideotrackdisplaysizeafterdecodingandcompensationforsampleshapeandsize.Aplayercanapplyadditionalscalingandadaptationsuchascroppingorpaddingtomatchimagestotheshapeandresolutionofthedisplaycurrentlyinuse.
4.2.2 Sample Description Box (‘stsd’)
TheSampleDescriptionBox(‘stsd’)inavideotrackSHALLincludeaNALStructuredVideoParameterSetthatcontains:
themaximumwidthandheightvaluescorrespondingtothemaximumcroppedhorizontalandverticalsamplecountsindicatedinanySequenceParameterSetinthetrack;and
aDecoderConfigurationRecordwhich: signalsthehighestProfile,Level,andotherparametersinthevideotrackasspecifiedin
[ISOVIDEO]Section8.3.3.1(HEVC)and[ISOVIDEO]Section5.3.3.1(AVC);and containsanarrayofinitializationNALunits(SPSandPPSNALsforAVCVideo,orVPS,SPS,
andPPSNALsforHEVCVideo)containingparametersmatchingthemaximumvaluesindicatedintheDecoderConfigurationRecord.
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containsa"MasteringdisplaycolourvolumeSEI”if"MasteringdisplaycolourvolumeSEI”ispresentinthevideotrack.
IftheSampleDescriptionBoxinavideotrackcontainsmorethanonevisualsampleentry,thenthevisualsampleentrywhichsatisfiestherequirementsaboveSHALLbestoredasthefirstvisualsampleentry.
4.2.3 Track Fragment Run Box (‘trun’)
ThesyntaxandvaluesforTrackFragmentRunBox(‘trun’)forvideotracksSHALLconformtoSection2.3.20withthefollowingadditionalconstraints:
Forsamplesinwhichpresentationtimestamp(PTS)anddecodetimestamp(DTS)differ,thesample-composition-time-offsets-presentflagSHALLbesetandcorrespondingvaluesprovided.
Thedata-offset-presentand sample-size-presentflagsSHALLbesetandcorrespondingvaluesprovided.
Thesample-duration-presentflagSHOULDbesetandcorrespondingvaluesprovided. ForAVCSampleEntry(‘avc3’)andHEVCSampleEntry(‘hev1’)NALStructuredVideo
tracks,the'first_sample_flags'SHALLsignalthepicturetypeofthefirstsampleineachDCCMovieFragmentasspecifiedbelow. sample_is_non_sync_sample=0:Ifthefirstsampleisasyncsample. sample_is_non_sync_sample=1:Ifthefirstsampleisnotasyncsample. sample_depends_on=2:IfthefirstsampleisanIframe.
4.2.4 Movie Fragment Box(‘moof’)
MovieFragmentsinvideotracksarerequiredtoconformtothefollowingconstrains: EveryvideotrackMovieFragmentexceptthelastMovieFragmentofavideotrackSHALLhavea
durationofatleastonesecond.ThelastMovieFragmentofavideotrackMAYhaveadurationoflessthanonesecond;and
EveryvideotrackMovieFragmentSHALLhaveadurationnogreaterthan10.01seconds.
4.2.5 Access Unit
ThestructureofanAccessUnitforpicturesinthevideotrackSHALLcomplywiththedatastructuredefinedinTable41‐.
Table4‐1–AccessUnitstructureforpicturesSyntaxElements Mandatory/OptionalAccessUnitDelimiterNAL MandatorySlicedata Mandatory
Asspecifiedin[ISOVIDEO],timinginformationprovidedwithinavideoelementarystreamSHOULDbeignored‐rather,timinginformationprovidedatthefileformatlevelSHALLbeused.
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4.2.6 Random Access Points
AsyncsampleorAVCRA‐Isample(seebelow)SHALLoccurevery3.003secondsorlesswithinaNALStructuredVideoTrack.ForAVCelementarystreams,anAVCRandomAccess(RA)I‐pictureisdefinedinthisspecificationasanI‐picturethatisfollowedinoutputorderbypicturesthatdonotreferencepicturesthatprecedetheAVCRAI‐pictureindecodingorder,asshowninFigure4‐1below.
Figure4‐1–ExampleofanAVCRandomAccess(RA)Ipicture
4.3 AVC
4.3.1 Storage of AVC Elementary Streams
AVCvideotracksSHALLcomplywithSection5of[ISOVIDEO].
4.3.1.1 VisualSampleEntry
Thesyntaxandvaluesforvisualsampleentry: SHALLconformtoAVCSampleEntry (‘avc1’)orAVCSampleEntry (‘avc3’)as
definedin[ISOVIDEO].;and SHOULDconformtoAVCSampleEntry (‘avc3’).
IfAVCSampleEntry(‘avc3’)isusedthefollowingrequirementsapply: IfthesampleisaSyncSample,allparametersetsneededfordecodingthatsampleSHALLbe
includedinthesampleitself. IfthesampleisarandomaccesspointthatisnotaSyncSample,allparametersetsneededfor
decodingthatsampleSHALLbeincludedinthesampleitself.
NO
Display Order Random Access (RA) I‐picture
OK
・・・
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4.3.1.2 AVCDecoderConfigurationRecord
SPSNALUnitsandPictureParameterSetNALUnitsMAYbemappedtoAVCDecoderConfigurationRecordasspecifiedin[ISOVIDEO]Section5.3.3“Decoderconfigurationinformation”andSection5.4“DerivationfromISOBaseMediaFileFormat”,withthefollowingadditionalconstraints:
AllSequenceParameterSetNALUnitsmappedtoAVCDecoderConfigurationRecordSHALLconformtotheconstraintsdefinedinSection4.3.2.2.
AllPictureParameterSetNALUnitsmappedtoAVCDecoderConfigurationRecordSHALLconformtotheconstraintsdefinedinSection4.3.2.3.
4.3.2 Constraints on [H264] Elementary Streams
4.3.2.1 Picturetype
AllpicturesSHALLbeencodedascodedframes,andSHALLNOTbeencodedascodedfields.
4.3.2.2 SequenceParameterSets(SPS)
SPSNALUnitsthatoccurwithinaDCCAVCvideotrackSHALLconformto[H264]withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLhavepre‐determinedvaluesasfollows: gaps_in_frame_num_value_allowed_flagSHALLbesetto0 vui_parameters_present_flagSHALLbesetto1
ThefollowingfieldsSHOULDhavepre‐determinedvaluesasfollows: frame_mbs_only_flagSHOULDbesetto1
ThevaluesofthefollowingfieldsSHALLNOTchangethroughoutan[H264]elementarystream: profile_idc level_idc
ThevaluesofthefollowingfieldsSHOULDNOTchangethroughoutan[H264]elementarystream: direct_8x8_inference_flag
IftheareadefinedbythewidthandheightfieldsoftheTrackHeaderBoxofavideotrack(seeSection2.3.5)sub‐sampledtothesampleaspectratiooftheencodedpictureformat,doesnotcompletelyfillallencodedmacroblocks,thenthefollowingadditionalconstraintsapply: frame_cropping_flagSHALLbesetto1toindicatethatAVCcroppingparametersare
present frame_crop_left_offsetandframe_crop_right_offsetSHALLbesetsuchastocrop
thehorizontalencodedpicturetothenearestevenintegerwidth(i.e.2,4,6,…)thatisequaltoorlargerthanthesub‐sampledwidthofthetrack
frame_crop_top_offsetandframe_crop_bottom_offsetSHALLbesetsuchastocroptheverticalpicturetothenearestevenintegerheightthatisequaltoorlargerthanthesub‐sampledheightofthetrack
Note:Giventhedefinitionabove,forMediaProfilesthatsupportdynamicsub‐sampling,ifthesampleaspectratiooftheencodedpictureformatchangeswithinthevideostream(i.e.duetoachangeinsub‐
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sampling),thenthevaluesofthecorrespondingcroppingparametersarerequiredtochangeaccordingly.Thus,itispossibleforAVCcroppingparameterstobepresentinoneportionofan[H264]elementarystream(i.e.wherecroppingisnecessary)andnotanother.Asspecifiedin[H264],whenframe_cropping_flagisequalto0,thevaluesofframe_crop_left_offset,frame_crop_right_offset,frame_crop_top_offset,andframe_crop_bottom_offsetareinferredtobeequalto0.
4.3.2.2.1 VisualUsabilityInformation(VUI)ParametersVUIparametersthatoccurwithinaDCCAVCvideotrackSHALLconformto[H264]withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLhavepre‐determinedvaluesasfollows: aspect_ratio_info_present_flagSHALLbesetto1 chroma_loc_info_present_flagSHALLbesetto0 timing_info_present_flagSHALLbesetto1 fixed_frame_rate_flagSHALLbesetto1 pic_struct_present_flagSHALLbesetto1,whenframe_mbs_only_flagissetto0
ThefollowingfieldsSHOULDhavepre‐determinedvaluesasfollows: pic_struct_present_flagSHOULDbesetto1 colour_description_present_flagSHOULDbesetto1
Note:Per[H264],ifthecolour_description_present_flagissetto1,thecolour_primaries,transfer_characteristicsandmatrix_coefficientsfieldsmustbedefinedinthe[H264]elementarystream
overscan_appropriate,ifpresent,SHOULDbesetto0 ThevaluesofthefollowingfieldsSHALLNOTchangethroughoutan[H264]elementarystream:
video_full_range_flag
low_delay_hrd_flagcolour_primaries,whenpresent transfer_characteristics,whenpresent matrix_coefficients,whenpresent
TheconditionofthefollowingSHALLNOTchangethroughoutan[H264]elementarystream: time_scale/num_units_in_tick/2
Note:Therequirementthatfixed_frame_rate_flagbesetto1andtheconditionthattime_scale/num_units_in_tick/2doesnotchangethroughoutastreamensuresafixedframeratethroughoutthe[H264]elementarystream.
ThevaluesofthefollowingfieldsSHOULDNOTchangethroughoutan[H264]elementarystream: max_dec_frame_buffering, colour_description_present_flag overscan_info_present_flag overscan_appropriate
4.3.2.3 PictureParameterSets(PPS)
PPSNALUnitsthatoccurwithinaDCCSHALLconformto[H264]withthefollowingadditionalconstraints: TheconditionofthefollowingfieldsSHALLNOTchangethroughoutan[H264]elementarystream:
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entropy_coding_mode_flag
4.3.2.4 MaximumBitrate
Themaximumbitrateof[H264]elementarystreamsSHALLbecalculatedbyimplementationofthebufferandtimingmodeldefinedin[H264]AnnexC.
4.3.2.5 Framerate
Theframerateof[H264]elementarystreamsSHALLbecalculatedasfollows:
frame rate = time_scale ÷ (2 * num_units_in_tick)Note:time_scale andnum_units_in_tickare[H264]codingparameters.BasedontherestrictionsdefinedinSection4.3.2.2.1,thisequationappliestoall[H264]elementarystreamsconformingtothisSpecification.
4.4 HEVC
4.4.1 Storage of HEVC Elementary Streams
HEVCvideotracksSHALLcomplywithSection8of[ISOVIDEO].
4.4.1.1 VisualSampleEntry
Thesyntaxandvaluesforvisualsampleentry: SHALLconformtoHEVCSampleEntry(‘hev1’)sampleentriesasdefinedin[ISOVIDEO].
ThefollowingrequirementsapplytoHEVCSampleEntry(‘hev1’): IfthesampleisaSyncSample,allparametersetsneededfordecodingthatsampleSHALLbe
includedinthesampleitself. IfthesampleisarandomaccesspointthatisnotaSyncSample,allparametersetsneededfor
decodingthatsampleSHALLbeincludedinthesampleitself.
4.4.1.2 HEVCDecoderConfigurationRecord
VPSNALUnits(NAL_unit_type=“VPS_NUT”),SPSNALUnits(NAL_unit_type=“SPS_NUT”)andPPSNALUnits(NAL_unit_type=“PPS_NUT”)MAYbemappedtoHEVCDecoderConfigurationRecordasspecifiedin[ISOVIDEO]Section8.3.3“Decoderconfigurationinformation”andSection8.4“DerivationfromISOBaseMediaFileFormat”,withthefollowingadditionalconstraints:
AllVideoParameterSetNALUnitsmappedtoHEVCDecoderConfigurationRecordSHALLconformtotheconstraintsdefinedinSection4.4.2.2.
AllSequenceParameterSetNALUnitsmappedtoHEVCDecoderConfigurationRecordSHALLconformtotheconstraintsdefinedinSection4.4.2.3.
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4.4.2 Constraints on [H265] Elementary Streams
4.4.2.1 Picturetype
AllpicturesSHALLbeencodedascodedframes,andSHALLNOTbeencodedascodedfields.
4.4.2.2 VideoParameterSets(VPS)
VPSNALUnitsthatoccurwithinaDCCHEVCtrackSHALLconformto[H265]withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLhavepre‐determinedvaluesasfollows: fixed_pic_rate_general_flag SHOULDbesetto1 general_interlaced_source_flagSHALLbesetto0
TheconditionofthefollowingfieldsSHALLNOTchangethroughoutan[H265]elementarystream: general_profile_space general_profile_idc general_tier_flag general_level_idc
4.4.2.3 SequenceParameterSets(SPS)
SPSNALUnitsthatoccurwithinaDCCHEVCtrackSHALLconformto[H265]withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLhavepre‐determinedvaluesasfollows: general_frame_only_constraint_flagSHOULDbesetto1 vui_parameters_present_flagSHALLbesetto1
IftheareadefinedbythewidthandheightfieldsoftheTrackHeaderBoxofavideotrack(seeSection2.3.5)sub‐sampledtothesampleaspectratiooftheencodedpictureformatdoesnotcompletelyfillallencodedcodingtreeunits,thefollowingadditionalconstraintsSHALLapply: conformance_window_flagSHALLbesetto1toindicatethatHEVCcroppingparameters
arepresent conf_win_left_offsetandconf_win_right_offsetSHALLbesetsuchastocropthe
horizontalencodedpicturetothenearestevenintegerwidth(i.e.2,4,6,…)thatisequaltoorlargerthanthesub‐sampledwidthofthetrack
conf_win_top_offsetandconf_win_bottom_offsetSHALLbesetsuchastocroptheverticalpicturetothenearestevenintegerheightthatisequaltoorlargerthanthesub‐sampledheightofthetrack
Note:Giventhedefinitionabove,forMediaProfilesthatsupportdynamicsub‐sampling,ifthesampleaspectratiooftheencodedpictureformatchangeswithinthevideostream(i.e.duetoachangeinsub‐sampling),thenthevaluesofthecorrespondingcroppingparametersarerequiredtochangeaccordingly.Thus,itispossibleforHEVCcroppingparameterstobepresentinoneportionofa[H265]elementarystream(i.e.wherecroppingisnecessary)andnotanother.Asspecifiedin[H265],whenconformance_window_flagisequalto0,thevaluesofconf_win_left_offset,conf_win_right, conf_win_top_offset,andconf_win_bottom_offsetareinferredtobeequalto0.
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4.4.2.3.1 VisualUsabilityInformation(VUI)ParametersVUIparametersthatoccurwithinaDCCHEVCtrackSHALLconformto[H265]withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLhavepre‐determinedvaluesasdefined: aspect_ratio_info_present_flagSHALLbesetto1 chroma_sample_loc_type_top_fieldandchroma_sample_loc_type_bottom_field
SHALLbesetto0or2,whenpresent vui_hrd_parameters_present_flagSHALLbesetto1 vui_timing_info_present_flagSHALLbesetto1 nal_hrd_parameters_present_flagSHALLbesetto1 ThefollowingfieldsSHOULDhavepre‐determinedvaluesasfollows: colour_description_present_flagSHOULDbesetto1.
Note:Per[H265],ifthecolour_description_present_flagissetto1,thecolour_primaries,transfer_characteristicsandmatrix_coefficientsfieldsmustbedefinedinthe[H265]elementarystream.
overscan_appropriate,ifpresent,SHOULDbesetto0. ThevaluesofthefollowingfieldsSHALLNOTchangethroughoutan[H265]elementarystream:
video_full_range_flag
chroma_loc_info_present_flag,whenpresent low_delay_hrd_flag
colour_primaries,whenpresent transfer_characteristics,whenpresent matrix_coeffs,whenpresent vui_time_scale vui_num_units_in_tick
Note:Therequirementthatfixed_pic_rate_generalbesetto1andthevaluesofvui_num_units_in_tickandvui_time_scalenotchangethroughoutastreamensuresafixedframeratethroughoutthe[H265]elementarystream.
ThevaluesofthefollowingfieldsSHOULDNOTchangethroughoutan[H265]elementarystream: colour_description_present_flag overscan_info_present_flag overscan_appropriate
4.4.2.4 SupplementalEnhancementInformation(SEI)
SEImessagesthatoccurwithinaDCCHEVCtrackSHALLconformto[H265]withthefollowingadditionalconstraints:
IftheMasteringdisplaycolourvolumeSEImessagedefinedin[H265]AnnexD.2.27exists,thepayloadvaluesSHALLNOTchangethroughoutthe[H265]elementarystream.
4.4.2.5 MaximumDelay
The(maximum)delayistheratiooftheCPBsize/max‐rate.ThedelaySHALLbelessthanorequalto8seconds
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4.4.2.6 MaximumBitrate
Themaximumbitrateof[H265]elementarystreamsSHALLbecalculatedbyimplementationofthebufferandtimingmodeldefinedin[H265]AnnexC.
4.4.2.7 FrameRate
Theframerateof[H265]elementarystreamsSHALLbecalculatedasfollows: frame rate = vui_time_scale ÷ vui_num_units_in_tick
Note:viu_time_scale andvui_num_units_in_tickare[H265]codingparameters.BasedontherestrictionsdefinedinSection4.4.2.3.1,thisequationappliestoall[H265]elementarystreamsconformingtothisSpecification.
4.5 Sub‐samplingandCropping
Inordertopromotetheefficientencodinganddisplayofvideocontent,croppingandsub‐samplingissupported.However,theextenttowhicheachissupportedisspecifiedineachMediaProfiledefinition(seetheMediaProfileAnnexesofthisspecification).
4.5.1 Sub‐sampling
Spatialsub‐samplingcanbeahelpfultoolforimprovingcodingefficiencyofavideoelementarystream.Itisachievedbyreducingtheresolutionofthecodedpicturerelativetothesourcepicture,whileadjustingthesampleaspectratiotocompensateforthechangeinpresentation.Forexample,byreducingthehorizontalresolutionofthecodedpictureby50%whileincreasingthesampleaspectratiofrom1:1to2:1,thecodedpicturesizeisreducedbyhalf.Whilethisdoesnotnecessarilycorrespondtoa50%decreaseintheamountofcodedpicturedata,thedecreasecannonethelessbesignificant.TheextenttowhichaCodedVideoSequenceissub‐sampledisprimarilyspecifiedbythecombinationofthefollowingsequenceparametersetfieldsinthevideoelementarystream:
[H264]: pic_width_in_mbs_minus1whichdefinesthenumberofhorizontalsamples pic_height_in_map_units_minus1,whichdefinesthenumberofverticalsamples aspect_ratio_idc,whichdefinestheaspectratioofeachsample
[H265]: pic_width_in_luma_sampleswhichdefinesthenumberofhorizontalsamples pic_height_in_luma_samples([H265])whichdefinesthenumberofverticalsamples aspect_ratio_idc,whichdefinestheaspectratioofeachsample
Thedisplaydimensionsofavideotrackaredefinedintermsofsquarepixels(i.e.1:1sampleaspectratio)inthewidthandheightfieldsoftheTrackHeaderBox(‘tkhd’)ofthevideotrack(seeSection2.3.5andSection4.2.1).Thesevaluesareusedtodeterminetheappropriateprocessingtoapplywhendisplayingthecontent.EachDeliveryTargetinthisspecification(seeAnnexC)definesconstraintsontheamountandnatureofspatialsub‐samplingthatispermittedbytheDeliveryTarget.
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4.5.1.1 Sub‐sampleFactor
Forthepurposeofthisspecification,theextentofsub‐samplingappliedischaracterizedbyasub‐samplefactorineachofthehorizontalandverticaldimensions,definedasfollows:
Thehorizontalsub‐samplefactorisdefinedastheratioofthenumberofcolumnsofthelumasamplearrayinafullencodedframeabsentofcroppingoverthenumberofcolumnsofthelumasamplearrayinapictureformat’sframeasspecifiedwithSAR1:1.
Theverticalsub‐samplefactorisdefinedastheratioofthenumberofrowsofthelumasamplearrayinafullencodedframeabsentofcroppingoverthenumberofrowsofthelumasamplearrayinapictureformat’sframeasspecifiedwithSAR1:1.
Thesub‐samplefactorisspecificallyusedforselectingappropriatewidthandheightvaluesfortheTrackHeaderBoxforvideotracks,asspecifiedinSection2.3.5.TheMediaProfiledefinitionsintheAnnexesofthisdocumentspecifythepictureformatsandthecorrespondingsub‐samplefactorsandsampleaspectratiosoftheencodedpicturethataresupportedforeachProfile.
4.5.1.1.1 ExamplesofSingleDimensionSub‐samplingIfa1920x1080squarepixel(SAR1:1)sourcepictureishorizontallysub‐sampledandencodedataresolutionof1440x1080(SAR4:3),whichcorrespondstoa1920x1080squarepixel(SAR1:1)pictureformat,thenthehorizontalsub‐samplefactoris14401920=0.75,whiletheverticalsub‐samplefactoris1.0sincethereisnochangeintheverticaldimension.Similarly,ifa1280x720(SAR1:1)sourcepictureisverticallysub‐sampledandencodedataresolutionof1280x540(SAR3:4),whichcorrespondstoa1280x720(SAR1:1)pictureformatframesize,thenthehorizontalsub‐samplefactoris1.0sincetheisnochangeinthehorizontaldimension,andtheverticalsub‐samplefactoris540720=0.75.
4.5.1.1.2 314BExampleofMixedSub‐samplingIfa1280x1080(SAR3:2)sourcepictureisverticallysub‐sampledandencodedataresolutionof1280x540(SAR3:4),correspondingtoa1920x1080squarepixel(SAR1:1)pictureformatframesize,thenthehorizontalsub‐samplefactoris12801920=2/3,andtheverticalsub‐samplefactoris5401080=0.5.Tounderstandhowthisisanexampleofmixedsub‐sampling,itishelpfultorememberthattheinitialsourcepictureresolutionof1280x1080(SAR3:2)canitselfbethoughtofashavingbeenhorizontallysub‐sampledfromahigherresolutionpicture.
4.5.2 Cropping to Active Picture Area
Anotherhelpfultoolforimprovingcodingefficiencyinavideoelementarystreamistheuseofcropping.Thisspecificationdefinesasetofrulesfordefiningencodingparameterstoreduceoreliminatetheneedtoencodenon‐essentialpicturedatasuchasblackmatting(i.e.“letterboxing”or“blackpadding”)thatfalloutsideoftheactivepictureareaoftheoriginalsourcecontent.ThedimensionsoftheactivepictureareaofavideotrackarespecifiedbythewidthandheightfieldsoftheTrackHeaderBox(‘tkhd’),asdescribedinSection2.3.5andSection4.2.1.Thesevaluesarespecifiedinsquarepixels,andtrackvideodataisnormalizedtothesedimensionsbeforeanytransformationordisplacementcausedbyacompositionsystemoradaptationtoaparticularphysicaldisplaysystem.
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Whensub‐samplingisapplied,asdescribedabove,thenumberofcodedsamplesisscaledinoneorbothdimensions.However,sincethesub‐sampledpictureareamightnotalwaysfallexactlyonthesamplecodingunitboundaryemployedbythevideoelementarystream,additionalcroppingparametersareusedtofurtherdefinethedimensionsofthecodedpicture.
[H264]: “Macroblocks”definethesamplecodingunitboundary(andare16x16blocks) SeetheprocessdefinedinSection4.3.2.2
[H265]: “CodingTreeUnits”definethesamplecodingunitboundary(andare64×64,32×32,or
16×16blocks) SeetheprocessdefinedinSection4.4.2.3
4.5.3 Relationship of Cropping and Sub‐sampling
Whenspatialsub‐samplingisapplied,additionalcroppingparametersareoftenneededtocompensateforthemismatchbetweenthecodedpicturesizeandthemacroblock([H264])/codingtreeunit([H265])boundaries.Thespecificrelationshipbetweenthesesmechanismsisdefinedasfollows:
Eachpictureisdecodedusingthecodingparameters,includingdecodedpicturesizeandcroppingfields,definedinthesequenceparametersetcorrespondingtothatpicture’sCodedVideoSequence.
ThedimensionsdefinedbythewidthandheightfieldsintheTrackHeaderBoxareusedtodeterminewhich,ifany,scalingorothercompositionoperationsarenecessaryfordisplay.Forexample,tooutputthevideotoanHDTV,thedecodedimagemightneedtobescaledtotheresolutiondefinedbywidthandheightandthenadditionalmattingapplied(ifnecessary)inordertoformavalidtelevisionvideosignal.
Figure4‐2–ExampleofEncodingProcessofLetterboxedSourceContent
Figure41‐showsanexampleoftheencodingprocessthatcanbeapplied.Table42‐showstheparametervaluesthatcouldbeused.
* AVC cropping can only operate on even numbers of lines, requiring that the selected height be rounded up
Source
Picture
(Letterboxed)
Source Picture
Letterboxed (2.35AspectRatio)
Sub‐sampled
Horizontally
(75%)
Encoded Active Picture
Source Frame: 1920 x 1080 Active Picture: 1920 x 818* Sample Aspect Ratio: 1:1
Source Frame: 1440 x1080ActivePicture:1440x818SampleAspectRatio:4:3
Encoded Frame: 1440x832
Active Picture: 1440 x 818 Sample Aspect Ratio: 4:3
Cropped to Active Picture
Cropped Frame:
1440x818 Active Picture: 1440 x 818 Sample Aspect Ratio: 4:3
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Table4‐2–ExampleSub‐sampleandCroppingValuesforFigure41‐Object Field Value
PictureFormat width 1920FrameSize height 1080
Sub‐sampleFactor horizontal 0.75 vertical 1.0
TrackHeaderBox width 1920 height 818
[H264]ParameterValues
chroma_format_idc 1(4:2:0)
aspect_ratio_idc 14(4:3)
pic_width_in_mbs_minus1 89 pic_height_in_map_units_minus1 51 frame_cropping_flag 1 frame_crop_left_offset 0 frame_crop_right_offset 0 frame_crop_top_offset 0 frame_crop_bottom_offset 7
[H265]ParameterValues
chroma_format_idc 1(4:2:0)MinCbSizeY 16log2_min_luma_coding_block_size_minus3 1aspect_ratio_idc 14(4:3)pic_width_in_luma_samples 1440pic_height_in_luma_samples 832conformance_window_flag 1conf_win_left_offset 0conf_win_right_offset 0conf_win_top_offset 0conf_win_bottom_offset 7
Notes: aschroma_format_idcis1,SubWidthCandSubWidthCaresetto2per[H264]and[H265].This
resultsinadoublingofframecropparameters(soframe_crop_bottom_offsetandconf_win_bottom_offsetbothequateto14pixelsintheaboveexample).
As[H265]MinCbSizeYis16andlog2_min_luma_coding_block_size_minus3is1,theCodingTreeUnitsizeis16x16(matchingthe[H264]macroblocksizeof16x16).
ThedecodinganddisplayprocessforthiscontentisillustratedinFigure42‐,below.Inthisexample,thedecodedpicturedimensionsare1440x818,onelinelargerthantheoriginalactivepicturearea.Thisisduetoalimitationinthecroppingparameterstocroponlyevenpairsoflines.
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Figure4‐3–ExampleofDisplayProcessforLetterboxedSourceContent
Figure43‐,below,illustrateswhatmighthappenwhenbothsub‐samplingandcroppingareworkinginthesamehorizontaldimension.Theoriginalsourcepicturecontentisfirstsub‐sampledhorizontallyfroma1:1sampleaspectratioat1920x1080toasampleaspectratioof4:3at1440x1080,thenthe1080x1080pixelactivepictureareaofthesub‐sampledimageisencoded.However,theactualcodedpicturehasaresolutionof1088x1088pixelsduetothecodingunitboundariesfallingonevenmultiplesof16pixelsinthisexample‐therefore,additionalcroppingparametersmustbeprovidedinbothhorizontalandverticaldimensions.
Figure4‐4–ExampleofEncodingProcessforPillarboxedSourceContent
Table43‐liststhevariousparametersthatmightappearintheresultingfileforthissamplecontent.Table4‐3–ExampleSub‐sampleandCroppingValuesforFigure43‐Object Field Value
PictureFormat width 1920FrameSize height 1080
Sub‐sampleFactor horizontal 0.75 vertical 1.0
TrackHeaderBox width 1440 height 1080
[H264]ParameterValues
chroma_format_idc 1(4:2:0)
aspect_ratio_idc 14(4:3)
pic_width_in_mbs_minus1 67
pic_height_in_map_units_minus1 67
frame_cropping_flag 1
Processed
for Display
Output
Decoded
Picture
Decoded Frame: 1440 x 818 Active Picture: 1440 x 818 Sample Aspect Ratio: 4:3
Scaled Horizontally to Square Pixels
Scaled Frame: 1920 x 818
Active Picture: 1920 x 818 Sample Aspect Ratio: 1:1
Display‐
specific
Scaled
Horizontally to Square Pixels
Letterboxed for HDTV Ouptut
Output
unchanged
for 2.35 portable
display
Source
Picture
(Letterboxed)
Source Picture
Pillarboxed (1.33Aspect
Ratio)
Cropped to
Active
Picture
Source Frame: 1920 x 1080 Active Picture: 1440 x 1080 Sample Aspect Ratio: 1:1
Coded Picture: 1080 x 1080
Sample Aspect Ratio: 4:3
Sub‐sampled
Horizontally
(75%)
Source Frame: 1440 x 1080
Active Picture: 1080 x 1080 Sample Aspect Ratio: 4:3
Encoded
Active
Picture
Encoded Frame: 1088 x 1088
Active Picture: 1080 x 1080 Sample Aspect Ratio: 4:3
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frame_crop_left_offset 0
frame_crop_right_offset 4
frame_crop_top_offset 0
frame_crop_bottom_offset 4
[H265]ParameterValues
chroma_format_idc 1(4:2:0)MinCbSizeY 16log2_min_luma_coding_block_size_minus3 1aspect_ratio_idc 14(4:3)pic_width_in_luma_samples 1088pic_height_in_luma_samples 1088conformance_window_flag 1conf_win_left_offset 0conf_win_right_offset 4conf_win_top_offset 0conf_win_bottom_offset 4
Notes: aschroma_format_idcis1,SubWidthCandSubWidthCaresetto2per[H264]and[H265].This
resultsinadoublingofframecropparameters(soframe_crop_bottom_offsetandconf_win_bottom_offsetbothequateto14pixelsintheaboveexample).
As[H265]MinCbSizeYis16andlog2_min_luma_coding_block_size_minus3is1,theCodingTreeUnitsizeis16x16(matchingthe[H264]macroblocksizeof16x16).
TheprocessforreconstructingthevideofordisplayisshowninFigure44‐.Asinthepreviousexample,thedecodedpictureisrequiredtobescaledbackuptotheoriginal1:1sampleaspectratio.
Figure4‐5–ExampleofDisplayProcessforPillarboxedSourceContent
Ifthiscontentwastobedisplayedonastandard4:3television,nofurtherprocessingoftheimagewouldbenecessary.However,ifthiscontentwastobedisplayedona16:9HDTV,itmightbenecessaryforittoapplyadditionalmattingontheleftandrightsidestoreconstructtheoriginalpillarboxesinordertoensurethevideoimagedisplaysproperly.
4.5.4 Dynamic Sub‐sampling
ForMediaProfilesthatsupportdynamicsub‐sampling,thespatialsub‐samplingofthecontentcanbechangedperiodicallythroughoutthedurationofthefile.Changestothesub‐samplingvaluesareimplementedbychangingtheelementarystreamparametervaluesidentifiedinSection4.5.1.Dynamic
DecodedPicture:1080x1080 SampleAspectRatio:4:3
Scaled
(logically)
to Track
Header
Dimensions
Track Header: 1440 x 1080
Sample Aspect Ratio: 1:1
Decoded
Picture
Processed
for Display
Output
Display‐
specific
Scaled to
SD
for output
SDTV
Pillarboxed
for HDTV
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sub‐samplingissupportedbyMediaProfilesthatdonotspecificallyprohibitthesevaluesfromchangingwithinavideotrack.
4.5.4.1 Constraintson[H264]ElementaryStreams
thepic_width_in_mbs_minus1,pic_height_in_map_units_minus1andaspect_ratio_idcsequenceparametersetfieldvaluesSHALLonlybechangedatthestartofafragment.
Whensub‐samplingparametersarechangedwithinthefile,theframe_cropping_flag,frame_crop_left_offset,frame_crop_right_offset,frame_crop_top_offset,frame_crop_bottom_offsetcroppingparametersSHALLalsobechangedtomatch,asspecifiedinSection4.3.2.2.
Note:Ifpic_width_in_mbs_minus1orpic_height_in_map_units_minus1changesfromthepreviousCodedVideoSequence,thisSHALLNOTimplyno_output_of_prior_pics_flagisequaltoone–inthiscasevideopresentationandoutputofallvideoframesSHOULDcontinuewithoutinterruptioninpresentation,i.e.nopicturesSHOULDbediscarded.
4.5.4.2 Constraintson[H265]ElementaryStreams
thepic_width_in_luma_samples,pic_height_in_luma_samplesandaspect_ratio_idcsequenceparametersetfieldvaluesSHALLonlybechangedatthestartofafragment.
Whensub‐samplingparametersarechangedwithinthefile,theconformance_window_flag, conf_win_left_offset, conf_win_right_offset, conf_win_top_offset,
conf_win_bottom_offsetcroppingparametersSHALLalsobechangedtomatch,asspecifiedinSection4.4.2.3.
Note:Ifpic_width_in_luma_samplesorpic_height_in_luma_sampleschangesfromthepreviousCodedVideoSequence,thisSHALLNOTimplyno_output_of_prior_pics_flagisequaltoone–inthiscasevideopresentationandoutputofallvideoframesSHOULDcontinuewithoutinterruptioninpresentation,i.e.nopicturesSHOULDbediscarded.
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5 AudioElementaryStreams
5.1 Introduction
ThischapterdescribestheaudiotrackinrelationtotheISOBaseMediaFile,therequiredvs.optionalaudioformatsandtheconstraintsoneachaudioformat.Ingeneral,thesystemlayerdefinitiondescribedin[MPEG4S]isusedtoembedtheaudio.ThisisdescribedindetailinSection5.2.
5.2 DataStructureforAudioTrack
ThecommondatastructureforstoringaudiotracksinaDCCisdescribedhere.Allrequiredandoptionalaudioformatscomplywiththeseconventions.
5.2.1 Track Header Box (‘tkhd’)
Foraudiotracks,thefieldsoftheTrackHeaderBoxSHALLbesettothevaluesspecifiedbelow.Therearesome“template”fieldsdeclaredtouse;see[ISO].
flags=0x000007,exceptforthecasewherethetrackbelongstoanalternategroup layer=0 volume=0x0100 matrix={0x00010000,0,0,0,0x00010000,0,0,0,0x40000000} width=0 height=0
5.2.2 Movie Fragment Box(‘moof’)
MovieFragmentsinaudiotracksarerequiredtoconformtothefollowingconstrains: EveryaudiotrackMovieFragmentexceptthelastMovieFragmentofanaudiotrackSHALLhavea
durationofatleastonesecond.ThelastMovieFragmentofanaudiotrackMAYhaveadurationoflessthanonesecond;and
EveryaudiotrackMovieFragmentSHALLhaveadurationnogreaterthan6seconds.
5.2.3 Sync Sample Box (‘stss’)
TheSyncSampleBox(‘stss’)SHALLNOTbeused.Note:“syncsample”inmoviefragmentscannotbesignaledbytheabsenceoftheSyncSamplebox(‘stss’)orbythepresenceoftheSyncSamplebox(‘stss’),sincethisboxisnotdesignedtolistsyncsamplesinmoviefragments.
Foraudioformatsinwhicheveryaudioaccessunitisarandomaccesspoint(syncsample),signalingcanbeachievedbyothermeanssuchassettingthe'sample_is_non_sync_sample'flagto"0"inthe'default_sample_flags'fieldintheTrackExtendsbox(‘trex’).
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Foraudioformatsinwhichsomeaudioaccessunitsarenotsyncsamples,syncsamplescanbesignaledusingsample_flagsintheTrackRunbox(‘trun’).
5.2.4 Handler Reference Box (‘hdlr’)
ThesyntaxandvaluesfortheHandlerReferenceBox(‘hdlr’)foraudiotracksSHALLconformto[ISO]withthefollowingadditionalconstraints:
Thehandler_typefieldSHALLbesetto“soun”
5.2.5 Sound Media Header Box (‘smhd’)
ThesyntaxandvaluesfortheSoundMediaHeaderBoxSHALLconformto[ISO]withthefollowingadditionalconstraints:
ThefollowingfieldsSHALLbesetasdefined: balance=0
5.2.6 Sample Description Box (‘stsd’)
ThecontentsoftheSampleDescriptionBox(‘stsd’)aredeterminedbyvalueofthehandler_typeparameterintheHandlerReferenceBox(‘hdlr’).Foraudiotracks,thehandler_typeparameterissetto“soun”,andtheSampleDescriptionBoxcontainsaaudiosampleentrythatdescribestheconfigurationoftheaudiotrack.ForeachoftheaudioformatssupportedbytheCommonFileFormat,aspecificaudiosampleentryboxthatisderivedfromtheAudioSampleEntryboxdefinedin[ISO]isused.Eachcodec‐specificSampleEntryboxisidentifiedbyauniquecodingnamevalue,andspecifiestheaudioformatusedtoencodetheaudiotrack,anddescribestheconfigurationoftheaudioelementarystream.Table51‐liststheaudioformatsthataresupportedbytheCommonFileFormat,andthecorrespondingSampleEntrythatispresentintheSampleDescriptionBoxforeachformat.
Table5‐1–DefinedAudioFormatscodingname AudioFormat SampleEntryType SectionReferencemp4a MPEG‐4AAC[2‐channel] MP4AudioSampleEntry Section5.3.2
MPEG‐4HEAACV2[5.1,7.1‐channel]
Section5.3.3
MPEG‐4HEAACv2 Section5.3.4
MPEG‐4HEAACv2withMPEGSurround
Section5.3.5
mha1 MPEG‐H3DAudio MHASampleEntry Section5.4ac‐3 AC‐3(DolbyDigital) AC3SampleEntry Section5.5.1
ec‐3EnhancedAC‐3(DolbyDigitalPlus)
EC3SampleEntry Section5.5.2
mlpa MLP MLPSampleEntry Section5.5.3ac‐4 AC‐4 AC4SampleEntry Section5.6.4dtsc DTS DTSSampleEntry Section5.6
dtshDTS‐HDwithcoresubstream
DTSSampleEntry Section5.6
dtsl DTS‐HDMasterAudio DTSSampleEntry Section5.6
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dtse DTS‐HDlowbitrate DTSSampleEntry Section5.6
5.2.7 Shared elements of AudioSampleEntry
ForallaudioformatssupportedbytheCommonFileFormat,thefollowingelementsoftheAudioSampleEntryboxdefinedin[ISO]areshared:class AudioSampleEntry(codingname) extends SampleEntry(codingname) { const unsigned int(32) reserved[2] = 0; template unsigned int(16) channelcount; template unsigned int(16) samplesize = 16; unsigned int(16) pre_defined = 0; const unsigned int(16) reserved = 0; template unsigned int(32) sampleRate; (codingnamespecific)Box }
ForallaudiotrackswithinaDCC,thevalueofthesamplesizeparameterSHALLbesetto16.EachoftheaudioformatssupportedbytheCommonFileFormatextendstheAudioSampleEntryboxthroughtheadditionofabox(shownaboveas“(codingnamespecific)Box”)containingcodec‐specificinformationthatisplacedwithintheAudioSampleEntry.Thisinformationisdescribedinthefollowingcodec‐specificsections.
5.3 MPEG‐4AACFormats
5.3.1 General Consideration for Encoding
SincetheAACcodecisbasedonoverlaptransform,anditdoesnotestablishaone‐to‐onerelationshipbetweeninput/outputaudioframesandaudiodecodingunits(AUs)inbit‐streams,itisnecessarytobecarefulinhandlingtimestampsinatrack.Figure51‐showsanexampleofanAACbit‐streaminthetrack.
Figure5‐1–ExampleofAACbit‐stream
Source
Coded bitstream
Enc
Dec
1 2 3 4 5
1,2 2,3 3,4 4,5
output N1 42 3
5,N
5
Dummy (Flush)
0 1 32 4 TimeStamp in track
TimeStamp for play(CTS ) 0 1 32 4
N,1 x
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Inthisfigure,thefirstblockofthebit‐streamisAU[1,2],whichiscreatedfrominputaudioframes[1]and[2].Dependingontheencoderimplementation,thefirstblockmightbeAU[N,1](whereNindicatesasilentintervalinsertedbytheencoder),butthistypeofAUcouldcausefailureinsynchronizationandthereforeSHALLNOTbeincludedinthefile.Toincludethelastinputaudioframe(i.e.,[5]ofsourceinthefigure)intothebit‐streamforencoding,itisnecessarytoterminateitwithasilentintervalandincludeAU[5,N]intothebit‐stream.Thisproducesthesamenumberofinputaudioframes,AUs,andoutputaudioframes,eliminatingtimedifference.Whenabit‐streamiscreatedusingthemethoddescribedabove,thedecodingresultofthefirstAUdoesnotnecessarilycorrespondtothefirstinputaudioframe.Thisisbecauseofthelackofthefirstpartofthebit‐streaminoverlaptransform.Thus,thefirstaudioframe(21msperframewhensampledat48kHz,forexample)isnotguaranteedtoplaycorrectly.Inthiscase,itisuptodecoderimplementationstodecidewhetherthedecodedoutputaudioframe[N1]istobeplayedormuted.Takingthisintoconsideration,thecontentSHOULDbecreatedbymakingthefirstinputaudioframeasilentinterval.
5.3.2 MPEG‐4 AAC LC [2‐Channel]
5.3.2.1 StorageofMPEG‐4AACLC[2‐Channel]ElementaryStreams
5.3.2.1.1 OverviewStorageofMPEG‐4AACLC[2‐channel]elementarystreamswithinaDCCSHALLbeaccordingto[MP4].Thefollowingadditionalconstraintsapplywhenstoring2‐channelMPEG‐4AACLCelementarystreamsinaDCC:
AnaudiosampleSHALLconsistofasingleAACaudioaccessunit. TheparametervaluesofAudioSampleEntry,DecoderConfigDescriptor,and
DecoderSpecificInfoSHALLbeconsistentwiththeconfigurationoftheAACaudiostream.
5.3.2.1.2 315BAudioSampleEntryBoxforMPEG‐4AACLC[2‐Channel]ThesyntaxandvaluesoftheAudioSampleEntrySHALLconformtoMP4AudioSampleEntry(‘mp4a’)asdefinedin[MP4],andthefollowingfieldsSHALLbesetasdefined:
channelcount=1(formono)or2(forstereo)ForMPEG‐4AAC,the(codingnamespecific)BoxthatextendstheMP4AudioSampleEntryistheESDBoxdefinedin[MP4],whichcontainsanES_Descriptor.
5.3.2.1.3 316BESDBoxThesyntaxandvaluesforES_DescriptorSHALLconformto[MPEG4S],andthefieldsoftheES_DescriptorSHALLbesettothefollowingspecifiedvalues.DescriptorsotherthanthosespecifiedbelowSHALLNOTbeused.
ES_ID=0 streamDependenceFlag=0 URL_Flag=0; OCRstreamFlag=0
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streamPriority=0 decConfigDescr=DecoderConfigDescriptor(seeSection5.3.2.1.3) slConfigDescr=SLConfigDescriptor,predefinedtype2
5.3.2.1.4 317BDecoderConfigDescriptorThesyntaxandvaluesforDecoderConfigDescriptorSHALLconformto[MPEG4S],andthefieldsofthisdescriptorSHALLbesettothefollowingspecifiedvalues.Inthisdescriptor,decoderSpecificInfoSHALLbeused,andProfileLevelIndicationIndexDescriptorSHALLNOTbeused.
objectTypeIndication=0x40(Audio) streamType=0x05(AudioStream) upStream=0 decSpecificInfo=AudioSpecificConfig(seeSection5.3.2.1.4)
5.3.2.1.5 AudioSpecificConfigThesyntaxandvaluesforAudioSpecificConfigSHALLconformto[AAC],andthefieldsofAudioSpecificConfigSHALLbesettothefollowingspecifiedvalues:
audioObjectType=2(AACLC) channelConfiguration=1(forsinglemono)or2(forstereo) GASpecificConfig(seeSection5.3.2.1.5)
ChannelassignmentSHALLNOTbechangedwithintheaudiostreamthatmakesupatrack.
5.3.2.1.6 GASpecificConfigThesyntaxandvaluesforGASpecificConfigSHALLconformto[AAC],andthefieldsofGASpecificConfigSHALLbesettothefollowingspecifiedvalues:
frameLengthFlag=0(1024linesIMDCT) dependsOnCoreCoder=0 extensionFlag=0
5.3.2.2 MPEG‐4AACLC[2‐Channel]ElementaryStreamConstraints
5.3.2.2.1 GeneralEncodingConstraintsMPEG‐4AAC[2‐Channel]elementarystreamsSHALLconformtotherequirementsoftheMPEG‐4AACprofileatLevel2asspecifiedin[AAC]withthefollowingrestrictions:
OnlytheMPEG‐4AACLCobjecttypeSHALLbeused. TheelementarystreamSHALLbeaRawDatastream.ADTSandADIFSHALLNOTbeused. ThetransformlengthoftheIMDCTforAACSHALLbe1024samplesforlongand128forshort
blocks. ThefollowingparametersSHALLNOTchangewithintheelementarystream
AudioObjectType SamplingFrequency ChannelConfiguration BitRate
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5.3.2.2.2 SyntacticElements ThesyntaxandvaluesforsyntacticelementsSHALLconformto[AAC].Thefollowingelements
SHALLNOTbepresentinanMPEG‐4AACelementarystream: coupling_channel_element(CCE)
5.3.2.2.2.1 ArrangementofSyntacticElements SyntacticelementsSHALLbearrangedinthefollowingorderforthechannelconfigurationsbelow.
<SCE><FIL><TERM>…formono <CPE><FIL><TERM>...forstereo
Note:Angledbrackets(<>)aredelimitersforsyntacticelements.
5.3.2.2.2.2 individual_channel_stream Thesyntaxandvaluesforindividual_channel_streamSHALLconformto[AAC].Thefollowing
fieldsSHALLbesetasdefined: gain_control_data_present=0
5.3.2.2.2.3 ics_info Thesyntaxandvaluesforics_infoSHALLconformto[AAC].ThefollowingfieldsSHALLbesetas
defined: predictor_data_present=0
5.3.2.2.2.4 MaximumBitrateThemaximumbitrateofMPEG‐4AACLC[2‐Channel]elementarystreamsSHALLbecalculatedinaccordancewiththeAACbufferrequirementsasdefinedinISO/IEC14496‐3:2009,section4.5.3.OnlytherawdatastreamSHALLbeconsideredindeterminingthemaximumbitrate(system‐layerdescriptorsareexcluded).
5.3.3 MPEG‐4 HE AAC V2[5.1, 7.1‐Channel]
5.3.3.1 Overview
NotethatcontentprovidersencodingcontentaccordingtotheHEAACV2ProfilecanuseanyofAAC‐LC,HE‐AACandHEAACV2profiles.ClientssupportingtheHEAACV2ProfilewillbeabletoplayAAC‐LC,HE‐AACandHEAACV2encodedcontent.
5.3.3.2 StorageofMPEG‐4HEAACV2[5.1,7.1‐Channel]ElementaryStreams
5.3.3.2.1 OverviewStorageofMPEG‐4HEAACV2[5.1,7.1‐Channel]elementarystreamswithinaDCCSHALLbeaccordingto[MP4].ThefollowingadditionalconstraintsapplywhenstoringMPEG‐4AACelementarystreamsinaDCC.
AnaudiosampleSHALLconsistofasingleAACaudioaccessunit.
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TheparametervaluesofAudioSampleEntry,DecoderConfigDescriptor,DecoderSpecificInfoandprogram_config_element(ifpresent)SHALLbeconsistentwiththeconfigurationoftheAACaudiostream.
5.3.3.2.2 AudioSampleEntryBoxforMPEG‐4HEAACV2[5.1,7.1‐Channel] ThesyntaxandvaluesoftheAudioSampleEntryboxSHALLconformtoMP4AudioSampleEntry
(‘mp4a’)asdefinedin[MP4],andthefollowingfieldsSHALLbesetasdefined: channelcountSHALLmatchthenumberofaudiochannels,includingtheLFE,inthe
streamForMPEG‐4HEAACV2[5.1,7.1‐Channel],the(codingnamespecific)BoxthatextendstheMP4AudioSampleEntryistheESDBoxdefinedin[MP4]thatcontainsanES_Descriptor
5.3.3.2.3 ESDBox ThesyntaxandvaluesforES_DescriptorSHALLconformto[MPEG4S],andthefieldsofthe
ES_DescriptorSHALLbesettothefollowingspecifiedvalues.DescriptorsotherthanthosespecifiedbelowSHALLNOTbeused. ES_ID=0 streamDependenceFlag=0 URL_Flag=0 OCRstreamFlag=0 streamPriority=0 decConfigDescr=DecoderConfigDescriptor(seeSection5.3.3.1.3) slConfigDescr=SLConfigDescriptor,predefinedtype2
5.3.3.2.4 DecoderConfigDescriptor ThesyntaxandvaluesforDecoderConfigDescriptorSHALLconformto[MPEG4S],andthefields
ofthisdescriptorSHALLbesettothefollowingspecifiedvalues.Inthisdescriptor,DecoderSpecificInfoSHALLalwaysbeused,andProfileLevelIndicationIndexDescriptorSHALLNOTbeused. objectTypeIndication=0x40(Audio) streamType=0x05(AudioStream) upStream=0 decSpecificInfo=AudioSpecificConfig(seeSection5.3.3.1.4)
5.3.3.2.5 AudioSpecificConfig ThesyntaxandvaluesforAudioSpecificConfigSHALLconformto[AAC]and[AACC],andthe
followingfieldsofAudioSpecificConfigSHALLbesettothespecifiedvalues: audioObjectType=2(AACLC) extensionAudioObjectType=5(SBR)ifSBRToolisused channelConfiguration=0or5or6or7or11or12or14 GASpecificConfig(seeSection5.3.3.1.5)
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5.3.3.2.5.1 channelConfiguration0 Thevalueof0forchannelConfigurationisallowedfor5.1‐channelstreamsonlyinthiscase,a
program_config_elementthatcontainsprogramconfigurationdataSHALLbeusedtospecifythecompositionofchannelelements.SeeSection5.3.3.1.6fordetailsontheprogram_config_element.ChannelassignmentSHALLNOTbechangedwithintheaudiostreamthatmakesupatrack.
5.3.3.2.6 GASpecificConfig ThesyntaxandvaluesforGASpecificConfigSHALLconformto[AAC]and[AACC],andthe
followingfieldsofGASpecificConfigSHALLbesettothespecifiedvalues: frameLengthFlag=0(1024linesIMDCT) dependsOnCoreCoder=0 extensionFlag=0 program_config_element(seeSection5.3.3.1.6)
5.3.3.2.7 program_config_element Thesyntaxandvaluesforprogram_config_element()(PCE)SHALLconformto[AAC],andthe
followingfieldsSHALLbesetasdefined: element_instance_tag=0 object_type=1(AACLC) num_front_channel_elements=2 num_side_channel_elements=0 num_back_channel_elements=1 num_lfe_channel_elements=1 num_assoc_data_elements=0or1 num_valid_cc_elements=0 mono_mixdown_present=0 stereo_mixdown_present=0 matrix_mixdown_idx_present=0or1 if (matrix_mixdown_idx_present = = 1) {
matrix_mixdown_idx=0to3 pseudo_surround_enable=0or1}
front_element_is_cpe[0]=0 front_element_is_cpe[1]=1 back_element_is_cpe[0]=1
5.3.3.3 MPEG‐4HEAACV2[5.1,7.1‐channel]ElementaryStreamConstraints
5.3.3.3.1 GeneralEncodingConstraintsMPEG‐4HEAACV2[5.1,7.1‐channel]elementarystreamsSHALLconformtotherequirementsoftheMPEG‐4AACprofileatLevel6asspecifiedin[AAC]withthefollowingrestrictions:
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TheelementarystreamSHALLbeaRawDatastream.ADTSandADIFSHALLNOTbeused. ThetransformframelengthofanAACframe(accessunit)SHALLbe1024samples(1024IMDCT
linesforlongand8times128forshortblocks. ThefollowingparametersSHALLNOTchangewithintheelementarystream:
AudioObjectType SamplingFrequency ChannelConfiguration
5.3.3.3.2 SyntacticElements ThesyntaxandvaluesforsyntacticelementsSHALLconformto[AAC]and[AACC].Thefollowing
elementsSHALLNOTbepresentinanMPEG‐4AACelementarystream: coupling_channel_element(CCE)
ThesyntaxandvaluesforsyntacticelementsSHALLconformto[AAC]and[AACC].ThefollowingelementsSHALLbepresentinanMPEG‐4AACelementarystream: dynamic_range_info()
5.3.3.3.2.1 6.1and7.1ChannelConfigurationsInadditiontotheabove,for6.1and7.1ChannelConfigurationfollowingelementsSHALLbepresentinanMPEG‐4AACelementarystream:
MPEG4_ancillary_data()
5.3.3.3.2.2 ArrangementofSyntacticElements SyntacticelementsSHALLbearrangedinthefollowing[AAC]i.e.orderingofchannelelements
SHALLfollowTable1.19–ChannelConfigurationof[AAC],forexample: <SCE><FIL‐<EXT‐SBR>><CPE><FIL‐<EXT‐SBR>><CPE><FIL‐<EXT‐SBR>><LFE>>…<FIL‐
<EXT‐DRC>><FIL><TERM>…forchannelConfiguration6(5.1‐channels)Note:Angledbrackets(<>)aredelimitersforsyntacticelements.
5.3.3.3.2.3 individual_channel_stream Thesyntaxandvaluesforindividual_channel_streamSHALLconformto[AAC]and[AACC].
ThefollowingfieldsSHALLbesetasdefined: gain_control_data_present=0;
5.3.3.3.2.4 ics_info Thesyntaxandvaluesforics_infoSHALLconformto[AAC]and[AACC].Thefollowingfields
SHALLbesetasdefined: predictor_data_present=0;
5.3.3.3.2.5 MaximumBitrateThemaximumbitrateofMPEG‐4HEAACV2[5.1,7.1‐Channel]elementarystreamsSHALLbecalculatedinaccordancewiththeAACbufferrequirementsasdefinedinISO/IEC14496‐3:2009,section4.5.3(288kbpsperfullaudiochannelat48kHzAACcoresamplingrate).OnlytherawdatastreamSHALLbeconsideredindeterminingthemaximumbitrate(system‐layerdescriptorsareexcluded).
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5.3.4 MPEG‐4 HE AAC v2
5.3.4.1 StorageofMPEG‐4HEAACv2ElementaryStreams
5.3.4.1.1 OverviewStorageofMPEG‐4HEAACv2elementarystreamswithinaDCCSHALLbeaccordingto[MP4].ThefollowingrequirementsSHALLbemetwhenstoringMPEG‐4HEAACv2elementarystreamsinaDCC.
AnaudiosampleSHALLconsistofasingleHEAACv2audioaccessunit. TheparametervaluesofAudioSampleEntry,DecoderConfigDescriptor,and
DecoderSpecificInfoSHALLbeconsistentwiththeconfigurationoftheMPEG‐4HEAACv2audiostream.
5.3.4.1.2 AudioSampleEntryBoxforMPEG‐4HEAACv2 ThesyntaxandvaluesoftheAudioSampleEntryboxSHALLconformtoMP4AudioSampleEntry
(‘mp4a’)definedin[MP4],andthefollowingfieldsSHALLbesetasdefined: channelcount=1(formonoorparametricstereo)or2(forstereo)
ForMPEG‐4AAC,the(codingnamespecific)BoxthatextendstheMP4AudioSampleEntryistheESDBoxdefinedinISO14496‐14[14],whichcontainsanES_Descriptor.
5.3.4.1.3 ESDBox TheESDBoxcontainsanES_Descriptor.ThesyntaxandvaluesforES_DescriptorSHALL
conformto[MPEG4S],andthefieldsoftheES_DescriptorSHALLbesettothefollowingspecifiedvalues.DescriptorsotherthanthosespecifiedbelowSHALLNOTbeused. ES_ID=0 streamDependenceFlag=0 URL_Flag=0 OCRstreamFlag=0(false) streamPriority=0 decConfigDescr=DecoderConfigDescriptor(seeSection5.3.4.1.3) slConfigDescr=SLConfigDescriptor,predefinedtype2
5.3.4.1.4 DecoderConfigDescriptor ThesyntaxandvaluesforDecoderConfigDescriptorSHALLconformto[MPEG4S],andthefields
ofthisdescriptorSHALLbesettothefollowingspecifiedvalues.Inthisdescriptor,DecoderSpecificInfoSHALLbeused,andProfileLevelIndicationIndexDescriptorSHALLNOTbeused. objectTypeIndication=0x40(Audio) streamType=0x05(AudioStream) upStream=0 decSpecificInfo=AudioSpecificConfig(seeSection5.3.4.1.4)
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5.3.4.1.5 AudioSpecificConfig ThesyntaxandvaluesforAudioSpecificConfigSHALLconformto[AAC]andthefieldsof
AudioSpecificConfigSHALLbesettothefollowingspecifiedvalues: audioObjectType=5(SBR) channelConfiguration=1(formonoorparametricstereo)or2(forstereo) underlyingaudioobjecttype=2(AACLC) GASpecificConfig(seeSection5.3.4.1.5)
ThisconfigurationusesexplicithierarchicalsignalingtoindicatetheuseoftheSBRcodingtool,andimplicitsignalingtoindicatetheuseofthePScodingtool.
5.3.4.1.6 GASpecificConfig ThesyntaxandvaluesforGASpecificConfigSHALLconformto[AAC],andthefieldsof
GASpecificConfigSHALLbesettothefollowingspecifiedvalues. frameLengthFlag=0(1024linesIMDCT) dependsOnCoreCoder=0 extensionFlag=0
5.3.4.2 MPEG‐4HEAACv2ElementaryStreamConstraints
5.3.4.2.1 OverviewNote:MPEG‐4HEAACv2isthesupersetofMPEG‐4AAC,MPEG‐4HEAACandMPEG‐4HEAACv2.
5.3.4.2.2 GeneralEncodingConstraintsTheMPEG‐4HEAACv2elementarystreamasdefinedin[AAC]SHALLconformtotherequirementsoftheMPEG‐4HEAACv2ProfileatLevel2,exceptasfollows:
TheelementarystreamMAYbeencodedaccordingtotheMPEG‐4AAC,HEAACorHEAACv2Profile.UseoftheMPEG‐4HEAACv2profileisrecommended.
TheaudioSHALLbeencodedinmono,parametricstereoor2‐channelstereo. ThetransformlengthoftheIMDCTforAACSHALLbe1024samplesforlongand128forshort
blocks. TheelementarystreamSHALLbeaRawDatastream.ADTSandADIFSHALLNOTbeused. ThefollowingparametersSHALLNOTchangewithintheelementarystream:
AudioObjectType SamplingFrequency ChannelConfiguration BitRate
5.3.4.2.3 SyntacticElements ThesyntaxandvaluesforsyntacticelementsSHALLconformto[AAC].Thefollowingelements
SHALLNOTbepresentinanMPEG‐4HEAACv2elementarystream: coupling_channel_element(CCE) program_config_element(PCE).
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5.3.4.2.3.1 ArrangementofSyntacticElements SyntacticelementsSHALLbearrangedinthefollowingorderforthechannelconfigurationsbelow.
<SCE><FIL><TERM>…formonoandparametricstereo <CPE><FIL><TERM>...forstereo
5.3.4.2.3.2 ics_info Thesyntaxandvaluesforics_infoSHALLconformto[AAC].ThefollowingfieldsSHALLbesetas
defined: predictor_data_present=0
5.3.4.2.3.3 MaximumBitrateThemaximumbitrateofMPEG‐4HEAACv2elementarystreamsinaDCCSHALLbecalculatedinaccordancewiththeAACbufferrequirementsasdefinedinISO/IEC14496‐3:2009,section4.5.3.OnlytherawdatastreamSHALLbeconsideredindeterminingthemaximumbitrate(system‐layerdescriptorsareexcluded).
5.3.5 MPEG‐4 HE AAC v2with MPEG Surround
5.3.5.1 Overview
Note:MPEG‐4HEAACv2isthesupersetofMPEG‐4AAC,MPEG‐4HEAACandMPEG‐4HEAACv2.
5.3.5.2 StorageofMPEG‐4HEAACv2ElementaryStreamswithMPEGSurround
StorageofMPEG‐4HEAACv2elementarystreamsthatcontainMPEGSurroundspatialaudiodatawithinaDCCSHALLbeaccordingto[MP4]and[AAC].TherequirementsdefinedinSection5.3.4.1SHALLbemetwhenstoringMPEG‐4HEAACv2elementarystreamscontainingMPEGSurroundspatialaudiodatainaDCC.Additionally:
ThepresenceofMPEGSurroundspatialaudiodatawithinanMPEG‐4AAC,HEAACorHEAACv2elementarystreamSHALLbeindicatedusingexplicitbackwardcompatiblesignalingasspecifiedin[AAC]. ThempsPresentFlagwithintheAudioSpecificConfigSHALLbesetto1.
5.3.5.3 MPEG‐4HEAACv2withMPEGSurroundElementaryStreamConstraints
5.3.5.3.1 337BGeneralEncodingConstraintsTheelementarystreamasdefinedin[AAC]and[MPS]SHALLbeencodedaccordingtothefunctionalitydefinedintheMPEG‐4AAC,HEAACorHEAACv2ProfileatLevel2,incombinationwiththefunctionalitydefinedinMPEGSurroundBaselineProfileLevel4,withthefollowingadditionalconstraints:
TheaudioSHALLbeencodedinmono,parametricstereoor2‐channelstereo. ThetransformlengthoftheIMDCTforAACSHALLbe1024samplesforlongand128forshort
blocks. TheelementarystreamSHALLbeaRawDatastream.ADTSandADIFSHALLNOTbeused.
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ThefollowingparametersSHALLNOTchangewithintheelementarystream: AudioObjectType SamplingFrequency ChannelConfiguration BitRate
TheMPEGSurroundpayloaddataSHALLbeembeddedwithinthecoreelementarystream,asspecifiedin[AAC]andSHALLNOTbecarriedinaseparateaudiotrack.
ThesamplingfrequencyoftheMPEGSurroundpayloaddataSHALLbeequaltothesamplingfrequencyofthecoreelementarystream.
SeparatefillelementsSHALLbeemployedtoembedtheSBR/PSextensiondataelementssbr_extension_data()andtheMPEGSurroundspatialaudiodataSpatialFrame().
ThevalueofbsFrameLengthSHALLbesetto15,31or63,resultingineffectiveMPEGSurroundframelengthsof1024,2048or4096timedomainsamplesrespectively.
AllaudioaccessunitsSHALLcontainanextensionpayloadoftypeEXT_SAC_DATA. TheintervalbetweenoccurrencesofSpatialSpecificConfiginthebit‐streamSHALLNOT
exceed500ms.WithinthecorrespondingSpatialFrame()thevalueofbsIndependencyFlagSHALLbesettoone.
Toensureconsistentdecoderbehaviorduringtrickplayoperations,thefirstAudioSampleofeachfragmentSHALLcontaintheSpatialSpecificConfigstructure.WithinthecorrespondingSpatialFrame()thevalueofbsIndependencyFlagSHALLbesettoone.
5.3.5.3.2 SyntacticElements ThesyntaxandvaluesforsyntacticelementsSHALLconformto[AAC]and[MPS].Thefollowing
elementsSHALLNOTbepresentinanMPEG‐4HEAACv2elementarystreamthatcontainsMPEGSurrounddata: coupling_channel_element(CCE) program_config_element(PCE).
5.3.5.3.2.1 ArrangementofSyntacticElements SyntacticelementsSHALLbearrangedinthefollowingorderforthechannelconfigurationsbelow:
<SCE><FIL><FIL><TERM>…formonoandparametricstereocoreaudiostreams <CPE><FIL><FIL><TERM>...forstereocoreaudiostreams
5.3.5.3.2.2 ics_info Thesyntaxandvaluesforics_infoSHALLconformto[AAC].ThefollowingfieldsSHALLbesetas
defined: predictor_data_present=0
5.3.5.3.2.3 MaximumBitrateThemaximumbitrateofMPEG‐4HEAACv2elementarystreamsthatcontainMPEGSurroundspatialaudiodataSHALLbecalculatedinaccordancewiththeAACbufferrequirementsasdefinedinISO/IEC14496‐
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3:2009,section4.5.3.OnlytherawdatastreamSHALLbeconsideredindeterminingthemaximumbitrate(system‐layerdescriptorsareexcluded).
5.4 MPEG‐H3DAudioFormat
5.4.1 Storage of MPEG‐H 3D AudioElementary Streams
5.4.1.1 Overview
StorageofMPEG‐H3DAudioelementarystreamswithinaDCCSHALLbeaccordingto[MHA],withthefollowingadditionalconstraints:
AnaudiosampleSHALLconsistofasingleMPEG‐H3DAudioaccessunit. TheparametervaluesofMHADecoderConfigurationRecordandMHASampleEntrySHALL
beconsistentwiththeconfigurationoftheMPEG‐H3DAudiostream.
5.4.1.2 AudioSampleEntryBoxforMPEG‐H3DAudio
ThesyntaxandvaluesoftheaudiosampleentrySHALLconformtoMHASampleEntry(‘mha1’)asdefinedin[MHA],andthefollowingfieldsSHALLbesetasdefined:
channelcountSHALLbesetto‘0’(inapplicable).TheMPEG‐H3DAudiodecoderiscapableofrenderingascenetoanygivenspeakersetup.ThereferenceChannelLayoutcarriedintheMHADecoderConfigurationRecordSHALLbeusedtosignalthepreferredreproductionlayoutforthisstreamandreplacesthechannelcountaccordingto[MHA].
configisanMHAConfigurationBoxwhichcontainstheMHADecoderConfigurationRecord.
5.4.1.3 MPEG‐H3DAudioDecoderConfigurationRecord
ThesyntaxandvaluesofMHADecoderConfigurationRecordSHALLconformto[MHA],andthefollowingfieldsSHALLbesetasdefined:
referenceChannelLayoutSHALLbe‘ChannelConfiguration’accordingto[CICP].
5.4.2 MPEG‐H 3D AudioElementary Stream Constraints
5.4.2.1 GeneralEncodingConstraints
MPEG‐H3DAudioSHALLconformto[MHA]withthefollowingrestrictions ThefollowingparametersSHALLnotchangewithintheMPEG‐H3DAudioelementarystream:
samplingfrequency audioframelength referenceloudspeakerlayout numberofaudiochannels numberofaudioobjects
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numberoftransportchannels
5.4.2.2 MaximumBitrate
ThemaximumbitrateofMPEG‐H3DAudioelementarystreamsinaDCCSHALLbecalculatedinaccordancewiththebufferrequirementsasdefinedin[MHA].OnlytherawdatastreamSHALLbeconsideredindeterminingthemaximumbitrate(systemlayerdescriptorsareexcluded).
5.5 AC‐3,EnhancedAC‐3,MLP,AC‐4andDTSFormatTimingStructure
UnliketheMPEG‐4audioformats,theDTSandDolbyformatsdonotoverlapbetweenframes.Synchronizedframesrepresentacontiguousaudiostreamwhereeachaudioframerepresentsanequalsizeblockofsamplesatagivensamplingfrequency.SeeFigure52‐forillustration.
Figure5‐2–Non‐AACbit‐streamexample
Additionally,unlikeAACaudioformats,theDTSandDolbyformatsdonotrequireexternalmetadatatosetupthedecoder,astheyarefullycontainedinthatregard.Descriptordataisprovided,however,toprovideinformationtothesystemwithoutrequiringaccesstotheelementarystream,astheESistypicallyencryptedintheDCC.
5.6 DolbyFormats
5.6.1 AC‐3 (Dolby Digital)
5.6.1.1 StorageofAC‐3ElementaryStreams
5.6.1.1.1 OverviewStorageofAC‐3elementarystreamswithinaDCCSHALLbeaccordingtoAnnexFof[EAC3].
AnaudiosampleSHALLconsistofasingleAC‐3frame.
1 2 3 4 5 6
Sequence of Synchronized Frames
1 2 3 4 5 6Decoded PCM audio
1 2 3 4 5 6Source PCM audio
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NotethatperAnnexFof[EAC3]theaudiostreamcanbeencodedeither"bigendian"or"littleendian"byteorder.BigendianSHOULDbeused.
5.6.1.1.2 AudioSampleEntryBoxforAC‐3ThesyntaxandvaluesoftheAudioSampleEntryboxSHALLconformtoAC3SampleEntry(‘ac-3’)asdefinedinAnnexFof[EAC3].TheconfigurationoftheAC‐3elementarystreamisdescribedintheAC3SpecificBox(‘dac3’)withinAC3SampleEntry,asdefinedinAnnexFof[EAC3].ForconveniencethesyntaxandsemanticsoftheAC3SpecificBoxarereplicatedinSection5.5.1.1.2.
5.6.1.1.3 AC3SpecificBoxThesyntaxoftheAC3SpecificBoxisshownbelow:Class AC3SpecificBox { unsigned int(2) fscod; unsigned int(5) bsid; unsigned int(3) bsmod; unsigned int(3) acmod; unsigned int(1) lfeon; unsigned int(5) bit_rate_code; unsigned int(5) reserved = 0; }
5.6.1.1.3.1 SemanticsThefscod,bsid,bsmod,acmodandlfeonfieldshavethesamemeaningandaresettothesamevalueastheequivalentparametersintheAC‐3elementarystream.Thebit_rate_code fieldisderivedfromthevalueoffrmsizcodintheAC‐3bit‐streamaccordingtoTable52‐.
Table5‐2–bit_rate_codebit_rate_code Nominalbitrate(kbit/s)00000 3200001 4000010 4800011 5600100 6400101 8000110 9600111 11201000 12801001 16001010 19201011 22401100 25601101 32001110 38401111 44810000 51210001 57610010 640
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ThecontentsoftheAC3SpecificBoxSHALLNOTbeusedtoconfigureorcontroltheoperationofanAC‐3audiodecoder.
5.6.1.2 AC‐3ElementaryStreamConstraints
5.6.1.2.1 OverviewAC‐3elementarystreamsSHALLcomplywiththesyntaxandsemanticsasspecifiedin[EAC3],notincludingAnnexE.AdditionalconstraintsonAC‐3audiostreamsarespecifiedinthissection.
5.6.1.2.2 GeneralEncodingConstraintsAC‐3elementarystreamsSHALLbeconstrainedasfollows:
TheminimumbitrateofanAC‐3elementarystreamSHALLbe64x103bits/second. Thefollowingbit‐streamparametersSHALLremainconstantwithinanAC‐3elementarystreamfor
thedurationofanAC‐3audiotrack: bsid bsmod acmod lfeon fscod frmsizcod
5.6.1.2.3 AC‐3synchronizationframeconstraints AC‐3synchronizationframesSHALLcomplywiththefollowingconstraints:
bsid–bit‐streamidentification:ThisfieldSHALLbesetto1000b(8),or110b(6)whenthealternatebit‐streamsyntaxdescribedinAnnexDof[EAC3]isused.
frmsizecod–framesizecode:ThisfieldSHALLbesettoavaluebetween001000bto100101b(64Kbpsto640Kbps).
acmod–audiocodingmode:Allaudiocodingmodesexceptdualmono(acmod =000b)definedinTable4‐3of[EAC3]arepermitted.
5.6.1.2.4 MaximumBitrateThemaximumbitrateofAC‐3elementarystreamsSHALLbecalculatedasthesamplesizedividedbytheduration.Note:TheminimumsamplesizeforAC‐3is256bytes(64Kbps).TherewillonlybeonesizevalueforthewholetrackasthestreamisCBR.Thedurationofthesampleis0.032seconds.
5.6.2 Enhanced AC‐3 (Dolby Digital Plus)
5.6.2.1 StorageofEnhancedAC‐3ElementaryStreams
5.6.2.1.1 OverviewStorageofEnhancedAC‐3elementarystreamswithinaDCCSHALLbeaccordingtoAnnexFof[EAC3].
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AnaudiosampleSHALLconsistofthenumberofsyncframesrequiredtodeliversixblocksofaudiodatafromeachsubstreamintheEnhancedAC‐3elementarystream(definedasanEnhancedAC‐3AccessUnit).
ThefirstsyncframeofanaudiosampleSHALLbethesyncframethathasastreamtypevalueof0(independent)andasubstreamIDvalueof0.
ForEnhancedAC‐3elementarystreamsthatconsistofsyncframescontainingfewerthan6blocksofaudio,thefirstsyncframeofanaudiosampleSHALLbethesyncframethathasastreamtypevalueof0(independent),asubstreamIDvalueof0,andhasthe“convsync”flagsetto“1”.
NotethatperAnnexFof[EAC3]theaudiostreamcanbeencodedeither"bigendian"or"littleendian"byteorder.BigendianSHOULDbeused.
5.6.2.1.2 344BAudioSampleEntryBoxforEnhancedAC‐3ThesyntaxandvaluesoftheAudioSampleEntryboxSHALLconformtoEC3SampleEntry(‘ec-3’)definedinAnnexFof[EAC3].TheconfigurationoftheEnhancedAC‐3elementarystreamisdescribedintheEC3SpecificBox(‘dec3’),withinEC3SampleEntry,asdefinedinAnnexFof[EAC3].ForconveniencethesyntaxandsemanticsoftheEC3SpecificBoxarereplicatedinSection5.5.2.1.2.
5.6.2.1.3 345BEC3SpecificBoxThesyntaxandsemanticsoftheEC3SpecificBoxareshownbelow.ThesyntaxshownisasimplifiedversionofthefullsyntaxdefinedinAnnexFof[EAC3],astheEnhancedAC‐3encodingconstraintsspecifiedinSection5.5.2.2restrictthenumberofindependentsubstreamsto1,soonlyasinglesetofindependentsubstreamparametersisincludedintheEC3SpecificBox.class EC3SpecificBox { unsigned int(13) data_rate; unsigned int(3) num_ind_sub; unsigned int(2) fscod; unsigned int(5) bsid; unsigned int(5) bsmod; unsigned int(3) acmod; unsigned int(1) lfeon; unsigned int(3) reserved = 0; unsigned int(4) num_dep_sub; if (num_dep_sub > 0) { unsigned int(9) chan_loc; } else { unsigned int(1) reserved = 0; } }
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5.6.2.1.3.1 Semantics data_rate–thisfieldindicatesthebitrateoftheEnhancedAC‐3elementarystreaminkbit/s.For
EnhancedAC‐3elementarystreamswithinaDCC,theminimumvalueofthisfieldis32. num_ind_sub–Thisfieldindicatesthenumberofindependentsubstreamsthatarepresentinthe
EnhancedAC‐3bit‐stream.Thevalueofthisfieldisonelessthanthenumberofindependentsubstreamspresent.ForEnhancedAC‐3elementarystreamswithinaDCC,thisfieldisalwayssetto0(indicatingthattheEnhancedAC‐3elementarystreamcontainsasingleindependentsubstream).
fscod–Thisfieldhasthesamemeaningandissettothesamevalueasthefscodfieldinindependentsubstream0.
bsid–Thisfieldhasthesamemeaningandissettothesamevalueasthebsidfieldinindependentsubstream0.
bsmod–Thisfieldhasthesamemeaningandissettothesamevalueasthebsmodfieldinindependentsubstream0.Ifthebsmodfieldisnotpresentinindependentsubstream0,thisfieldSHALLbesetto0.
acmod–Thisfieldhasthesamemeaningandissettothesamevalueastheacmodfieldinindependentsubstream0.
lfeon–Thisfieldhasthesamemeaningandissettothesamevalueasthelfeonfieldinindependentsubstream0.
num_dep_sub–Thisfieldindicatesthenumberofdependentsubstreamsthatareassociatedwithindependentsubstream0.ForEnhancedAC‐3elementarystreamswithinaDCC,thisfieldMAYbesetto0or1.
chan_loc–Ifthereisadependentsubstreamassociatedwithindependentsubstream,thisbitfieldisusedtoidentifychannellocationsbeyondthoseidentifiedusingtheacmodfieldthatarepresentinthebit‐stream.Foreachchannellocationorpairofchannellocationspresent,thecorrespondingbitinthechan_locbitfieldissetto"1",accordingtoTable53‐.Thisinformationisextractedfromthechanmapfieldofthedependentsubstream.
Table5‐3–chan_locfieldbitassignmentsBit Location0 Lc/Rcpair1 Lrs/Rrspair2 Cs3 Ts4 Lsd/Rsdpair5 Lw/Rwpair6 Lvh/Rvhpair7 Cvh8 LFE2
ThecontentsoftheEC3SpecificBoxSHALLNOTbeusedtocontroltheconfigurationoroperationofanEnhancedAC‐3audiodecoder.
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5.6.2.2 EnhancedAC‐3ElementaryStreamConstraints
5.6.2.2.1 OverviewEnhancedAC‐3elementarystreamsSHALLcomplywiththesyntaxandsemanticsasspecifiedin[EAC3],includingAnnexE.AdditionalconstraintsonEnhancedAC‐3audiostreamsarespecifiedinthissection.
5.6.2.2.2 346BGeneralEncodingConstraintsEnhancedAC‐3elementarystreamsSHALLbeconstrainedasfollows:
TheminimumbitrateofanEnhancedAC‐3elementarystreamSHALLbe32x103bits/second. AnEnhancedAC‐3elementarystreamSHALLalwayscontainatleastoneindependentsubstream
(streamtype0)withasubstreamIDof0.AnEnhancedAC‐3elementarystreamMAYalsoadditionallycontainonedependentsubstream(streamtype1).
Thefollowingbit‐streamparametersSHALLremainconstantwithinanEnhancedAC‐3elementarystreamforthedurationofanEnhancedAC‐3track: Numberofindependentsubstreams Numberofdependentsubstreams Withinindependentsubstream0:
o bsido bsmod o acmod o lfeon o fscod
Withindependentsubstream0:o bsid o acmod o lfeon o fscod o chanmap
5.6.2.2.3 Independentsubstream0constraintsIndependentsubstream0consistsofasequenceofEnhancedAC‐3synchronizationframes.ThesesynchronizationframesSHALLcomplywiththefollowingconstraints:
bsid–bit‐streamidentification:Ifindependentsubstream0istheonlysubstreamintheEnhancedAC‐3elementarystream,thisfieldSHALLbesetto10000b(16).IftheEnhancedAC‐3elementarystreamcontainsbothindependentsubstream0anddependentsubstream0,thisfieldSHALLbesetto00110(6),01000(8)or10000(16).
Whenbsid=10000b(16),then: strmtyp–streamtype:ThisfieldSHALLbesetto00b(StreamType0–independent
substream);and substreamid–substreamidentification:ThisfieldSHALLbesetto000b(substreamID=
0). acmod–audiocodingmode:Allaudiocodingmodesexceptdualmono(acmod=000b)definedin
Table4‐3of[EAC3]arepermitted.Audiocodingmodedualmono(acmod=000b)SHALLNOTbeused.
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5.6.2.2.4 DependentsubstreamconstraintsDependentsubstream0consistsofasequenceofEnhancedAC‐3synchronizationframes.ThesesynchronizationframesSHALLcomplywiththefollowingconstraints:
bsid–bit‐streamidentification:ThisfieldSHALLbesetto10000b(16). strmtyp–streamtype:ThisfieldSHALLbesetto01b(StreamType1–dependentsubstream). substreamid–substreamidentification:ThisfieldSHALLbesetto000b(substreamID=0). acmod–audiocodingmode:Allaudiocodingmodesexceptdualmono(acmod=000b)definedin
Table4‐3of[EAC3]arepermitted.Audiocodingmodedualmono(acmod=000b)SHALLNOTbeused.
5.6.2.2.5 Substreamconfigurationfordeliveryofmorethan5.1channelsofaudioTodelivermorethan5.1channelsofaudio,bothindependent(StreamType0)anddependent(StreamType1)substreamsareincludedintheEnhancedAC‐3elementarystream.Thechannelconfigurationofthecompleteelementarystreamisdefinedbytheacmodparametercarriedintheindependentsubstream,andtheacmodandchanmapparameterscarriedinthedependentsubstream.TheloudspeakerlocationssupportedbyEnhancedAC‐3aredefinedin[SMPTE428].Thefollowingrulesapplytochannelnumbersandsubstreamuse:
Whenmorethan5.1channelsofaudioaretobedelivered,independentsubstream0ofanEnhancedAC‐3elementarystreamSHALLbeconfiguredasadownmixofthecompleteprogram.
Additionalchannelsnecessarytodeliverupto7.1channelsofaudioSHALLbecarriedindependentsubstream0.
5.6.2.2.6 MaximumBitrateThemaximumbitrateofEnhancedAC‐3elementarystreamsSHALLbecalculatedasthesamplesizedividedbytheduration.Note:TheminimumsamplesizeofEnhancedAC‐3is128bytes(32Kbps).Astherearealwayssixblocksofaudiodatafromeverysubstreampresentinthesample,thedurationofeachsampleisthesameasAC‐3–0.032seconds.
5.6.3 MLP (Dolby TrueHD)
5.6.3.1 StorageofMLPelementarystreams
5.6.3.1.1 OverviewStorageofMLPelementarystreamswithinaDCCSHALLbeaccordingto[MLPISO].
AnaudiosampleSHALLconsistofasingleMLPaccessunitasdefinedin[MLP].
5.6.3.1.2 AudioSampleEntryBoxforMLPThesyntaxandvaluesoftheAudioSampleEntryboxSHALLconformtoMLPSampleEntry(‘mlpa’)definedin[MLPISO].
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WithinMLPSampleEntry,thesampleRatefieldhasbeenredefinedasasingle32‐bitintegervalue,ratherthanthe16.16fixed‐pointfielddefinedintheISObasemediafileformat.Thisenablesexplicitsupportforsamplingfrequenciesgreaterthan48kHz.TheconfigurationoftheMLPelementarystreamisdescribedintheMLPSpecificBox(‘dmlp’),withinMLPSampleEntry,asdescribedin[MLPISO].ForconveniencethesyntaxandsemanticsoftheMLPSpecificBoxarereplicatedinSection5.5.3.1.2.
5.6.3.1.3 MLPSpecificBoxThesyntaxandsemanticsoftheMLPSpecificBoxareshownbelow:Class MLPSpecificBox { unsigned int(32) format_info; unsigned int(15) peak_data_rate; unsigned int(1) reserved = 0; unsigned int(32) reserved = 0; }
5.6.3.1.3.1 Semantics format_info–Thisfieldhasthesamemeaningandissettothesamevalueastheformat_info
fieldintheMLPbit‐stream. peak_data_rate –Thisfieldhasthesamemeaningandissettothesamevalueasthe
peak_data_rate fieldintheMLPbit‐stream.ThecontentsoftheMLPSpecificBoxSHALLNOTbeusedtocontroltheconfigurationoroperationofanMLPaudiodecoder.
5.6.3.2 MLPElementaryStreamConstraints
5.6.3.2.1 OverviewMLPelementarystreamsSHALLcomplywiththesyntaxandsemanticsasspecifiedin[MLP].AdditionalconstraintsonMLPaudiostreamsarespecifiedinthissection.
5.6.3.2.2 GeneralEncodingConstraintsMLPelementarystreamsSHALLbeconstrainedasfollows:
AllMLPelementarystreamsSHALLcomplywithMLPFormBsyntax,andthestreamtypeSHALLbeFBAstreams.
ThesamplerateofallsubstreamswithintheMLPbit‐streamSHALLbeidentical. ThefollowingparametersSHALLremainconstantwithinanMLPelementarystreamforthe
durationofanMLPaudiotrack. audio_sampling_frequency –samplingfrequency substreams –numberofMLPsubstreams min_chanandmax_chan ineachsubstream–numberofchannels 6ch_source_formatand8ch_source_format–audiochannelassignment substream_info–substreamconfiguration
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5.6.3.2.3 MLPaccessunitconstraints Samplerate–ThesamplerateSHALLbeidenticalonallchannels. Samplingphase–ThesamplingphaseSHALLbesimultaneousforallchannels. Wordsize–ThequantizationofsourcedataandofcodeddataMAYbedifferent.Thequantization
ofcodeddataisalways24bits.Whenthequantizationofsourcedataisfewerthan24bits,thesourcedataispaddedto24bitsbyaddingbitsofzero(‘0’)astheleastsignificantbit(s).
2‐chdecodersupport–ThestreamSHALLincludesupportfora2‐chdecoder. 6‐chdecodersupport–ThestreamSHALLincludesupportfora6‐chdecoderwhenthetotal
streamcontainsmorethan6channels. 8‐chdecodersupport–ThestreamSHALLincludesupportforan8‐chdecoder.
5.6.3.2.4 LoudspeakerAssignmentsTheMLPelementarystreamsupports2‐channel,6‐channeland8‐channelpresentations.Loudspeakerlayoutoptionsaredescribedforeachpresentationinthestream.PleaserefertoAppendixEof“MeridianLosslessPacking‐TechnicalReferenceforFBAandFBBstreams”Version1.0.TheloudspeakerlocationssupportedbyMLParedefinedin[SMPTE428].
5.6.3.2.5 MaximumBitrateThemaximumbitrateofMLPelementarystreamsSHALLbecalculatedaccordingtoMLPTechRef[MLP]Section8.8.1.
5.6.4 AC‐4
5.6.4.1 StorageofAC‐4ElementaryStreams
5.6.4.1.1 OverviewStorageofAC‐4elementarystreamswithinaDCCSHALLbeaccordingtoAnnexEof[AC4].
5.6.4.1.2 344BAudioSampleEntryBoxforAC‐4ThesyntaxandvaluesoftheAudioSampleEntryboxSHALLconformtoAC4SampleEntry(‘ac-4’)definedinAnnexE,clause3of[AC4].TheconfigurationoftheAC‐4elementarystreamisdescribedintheAC4SpecificBox(‘dac4’),withintheAC4SampleEntry,asdefinedinAnnexE,clause4of[AC4].AdditionalrulesforAC‐4audiotracksinfragmentedISOBMFFmediaformataredefinedinAnnexE,clause5of[AC4].
5.6.4.2 AC‐4ElementaryStreamConstraints
5.6.4.2.1 OverviewAC‐4elementarystreamsSHALLcomplywiththesyntaxandsemanticsasspecifiedin[AC4].AdditionalconstraintsonAC‐4audiostreamsarespecifiedinthissection.
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5.6.4.2.2 346BGeneralEncodingConstraintsAC‐4elementarystreamsSHALLbeconstrainedasfollows:
TheminimumbitrateofanAC‐4elementarystreamSHALLbe32x103bits/second.
5.6.4.2.3 MaximumBitrateThemaximumbitrateofAC‐4elementarystreamsSHALLbecalculatedasthesumofallsamplesizesdividedbytheaccumulateddurationofallsamples.
5.7 DTSFormats
5.7.1 Storage of DTS elementary streams
StorageofDTSformatswithinaDCCSHALLbeaccordingtothisspecification. AnaudiosampleSHALLconsistofasingleDTSaudioframe,asdefinedin[DTS].
5.7.1.1 AudioSampleEntryBoxforDTSFormats
ThesyntaxandvaluesoftheAudioSampleEntryBoxSHALLconformtoDTSSampleEntry.TheparametersampleRateSHALLbesettoeitherthesamplingfrequencyindicatedbySFREQinthecoresubstreamortothefrequencyrepresentedbytheparameternuRefClockCodeintheextensionsubstream.TheconfigurationoftheDTSelementarystreamisdescribedintheDTSSpecificBox(‘ddts’),withinDTSSampleEntry.ThesyntaxandsemanticsoftheDTSSpecificBoxaredefinedinthefollowingsection.TheparameterchannelcountSHALLbesettothenumberofdecodableoutputchannelsinbasicplayback,asdescribedinthe(‘ddts’) configurationbox.
5.7.1.2 DTSSpecificBox
ThesyntaxandsemanticsoftheDTSSpecificBoxareshownbelow.class DTSSpecificBox { unsigned int(32) size; //Box.size unsigned char[4] type=‘ddts’; //Box.type unsigned int(32) DTSSamplingFrequency; unsigned int(32) maxBitrate; unsigned int(32) avgBitrate; unsigned char reserved = 0; bit(2) FrameDuration; // 0=512, 1=1024, 2=2048, 3=4096 bit(5) StreamConstruction; // Table 5-4 bit(1) CoreLFEPresent; // 0=none; 1=LFE exists bit(6) CoreLayout; //
StreamConstructionCoreSubstream ExtensionSubstream
Core XCH X96 XXCH Core XXCH X96 XBR XLL LBR
1
2
3
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StreamConstructionCoreSubstream ExtensionSubstream
Core XCH X96 XXCH Core XXCH X96 XBR XLL LBR
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Table 5-5 bit(14) CoreSize; // FSIZE, Not to exceed 4064 bytes bit(1) StereoDownmix // 0=none; 1=emb. downmix present bit(3) RepresentationType; // Table 5-6 bit(16) ChannelLayout; // Table 5-7 bit(1) MultiAssetFlag = 0; bit(1) LBRDurationMod = 0; bit(1) ExpansionBoxPresent; // 0=no ExpansionBox, 1=ExpansionBox present bit(5) reserved = 0; DTSExpansionBox[] boxes; // zero or more expansion boxes }
5.7.1.2.1 Semantics DTSSamplingFrequency–Themaximumsamplingfrequencystoredinthecompressedaudio
stream. maxBitrate–Thepeakbitrate,inbitspersecond,oftheaudioelementarystreamfortheduration
ofthetrack.Thecalculatedvaluewillberoundeduptothenearestinteger. avgBitrate–Theaveragebitrate,inbitspersecond,oftheaudioelementarystreamforthe
durationofthetrack.Thecalculatedvaluewillberoundeduptothenearestinteger. FrameDuration–Thiscoderepresentsthenumberofaudiosamplesdecodedinacompleteaudio
accessunitatDTSSamplingFrequency.
CoreLayout–ThisparameterisidenticaltotheDTSCoresubstreamheaderparameterAMODE[DTS]andrepresentsthechannellayoutofthecoresubstreampriortoapplyinganyinformationstoredinanyextensionsubstream.See
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StreamConstructionCoreSubstream ExtensionSubstream
Core XCH X96 XXCH Core XXCH X96 XBR XLL LBR
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Table5‐5.Ifnocoresubstreamexists,thisparameterSHALLbeignored. CoreLFEPresent–IndicatesthepresenceofanLFEchannelinthecore.Ifnocoreexists,this
valueSHALLbeignored. StreamConstructon–Providescompleteinformationontheexistenceandoflocationof
extensionsinanysynchronizedframe.SeeTable5‐4. ChannelLayout–ThisparameterisidenticaltonuSpkrActivitymask definedintheextension
substreamheader[DTS].This16‐bitparameterthatprovidescompleteinformationonchannelscodedintheaudiostreamincludingcoreandextensions.SeeTable5‐7.ThebinarymasksofthechannelspresentinthestreamareaddedtogethertocreateChannelLayout.
StereoDownmix –Indicatesthepresenceofanembeddedstereodownmixinthestream.Thisparameterisnotvalidforstereoormonostreams.
CoreSize–ThisparameterisderivedfromFSIZEinthecoresubstreamheader[DTS]anditrepresentsacoreframepayloadinbytes.Inthecasewhereanextensionsubstreamexistsinanaccessunit,thisrepresentsthesizeofthecoreframepayloadonly.ThissimplifiesextractionofjustthecoresubstreamfordecodingorexportingoninterfacessuchasS/PDIF.ThevalueofCoreSizewillalwaysbelessthanorequalto4064bytes.InthecasewhenCoreSize=0,CoreLayoutandCoreLFEPresentSHALLbeignored.ChannelLayoutwillbeusedtodeterminechannelconfiguration.
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RepresentationType –ThisparameterisderivedfromthevaluefornuRepresentationtypeinthesubstreamheader[DTS].Thisindicatesspecialpropertiesoftheaudiopresentation.SeeTable5‐6.ThisparameterisonlyvalidwhenallflagsinChannelLayoutaresetto0.IfChannelLayout≠0,thisvalueSHALLbeignored.
Channel Layout‐Providescompleteinformationonchannelscodedintheaudiostreamincludingcoreandextensions.Thebinarymasksofthechannelspresent,asshowninTableTable5‐7,areaddedtogethertocreateChannelLayout.
MultiAssetFlag – Thisflagshallbesetifthestreamcontainsmorethanoneasset.ThisalsoimpliesthataDTSextensionsubstreamispresent.Multipleassetstreamsshallusethe‘dtsh’codingtype.Whenmultipleassetsexist,theremainingparametersintheDTSSpecificBoxonlyreflectthecodingparametersofthefirstasset.
LBRDurationMod – ThisflagindicatesaspecialcaseoftheLBRcodingbandwidth,resultingin1/3or2/3bandlimiting.TheresultofthisistheLBRframedurationis50%largerthanindicatedinFrameDuration.Forexample,whenthisflagissetto1,theFrameDurationis6144samplesinsteadof4096samples.
ExpansionBoxPresent - Thisflagindicatesthatatleast1boxoccupiestheExpansionBoxplaceholder.
DTSExpansionBox – Thisbox,ifpresent,willcontainadditionalprivateboxes.IfExpansionBoxPresent=1,oneormoreadditionalprivateboxesto‘ddts’arepresent.Playbackdevicesnotcapableofsupportingtheseboxeswillbeabletorelyonthedefinedparametersin‘ddts’forbasicplaybackcapability.SelectprivateboxesthatmayappearintheExpansionBoxaredefinedinsection5.7.1.3.
Table5‐4–StreamConstruction
StreamConstructionCoreSubstream ExtensionSubstream
Core XCH X96 XXCH Core XXCH X96 XBR XLL LBR
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
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StreamConstructionCoreSubstream ExtensionSubstream
Core XCH X96 XXCH Core XXCH X96 XBR XLL LBR
19
20
21
Table5‐5–CoreLayout
CoreLayout Description0 Mono(1/0)2 Stereo(2/0)4 LT,RT(2/0)5 L,C,R(3/0)6 L,C,R,S(2/1)7 L,R,S(3/1)8 L,R.LS,RS(2/2)
9L,C,R,LS,RS(3/2)
Table5‐6–RepresentationTypeRepresentationType Description000b Audioassetdesignatedformixingwithanotheraudioasset001b Reserved
010bLt/RtEncodedformatrixsurrounddecoding;itimpliesthattotalnumberofencodedchannelsis2
011bAudioprocessedforheadphoneplayback;itimpliesthattotalnumberofencodedchannelsis2
100b NotApplicable101b–111b Reserved
Table5‐7–ChannelLayoutNotation LoudspeakerLocationDescription BitMasks NumberofChannels
C Centerinfrontoflistener 0x0001 1
LR Left/Rightinfront 0x0002 2
LsRs Left/Rightsurroundonsideinrear 0x0004 2
LFE1 Lowfrequencyeffectssubwoofer 0x0008 1
Cs Centersurroundinrear 0x0010 1
LhRh Left/Rightheightinfront 0x0020 2
LsrRsr Left/Rightsurroundinrear 0x0040 2
Ch CenterHeightinfront 0x0080 1
Oh Overthelistener’shead 0x0100 1
LcRc Betweenleft/rightandcenterinfront 0x0200 2
LwRw Left/Rightonsideinfront 0x0400 2
LssRss Left/Rightsurroundonside 0x0800 2
LFE2 Secondlowfrequencyeffectssubwoofer 0x1000 1
LhsRhs Left/Rightheightonside 0x2000 2
Chr Centerheightinrear 0x4000 1
LhrRhr Left/Rightheightinrear 0x8000 2
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5.7.1.3 DTSExpansionBox
IfExpansionBoxPresentissetto1,thenoneormoreprivateboxesreferredtoasDTSExpansionBoxescanbefoundattheendofthe‘ddts’box,fillingtheremainingspaceofthebox.Asdefinedin[ISO]section4.2,boxeswithanunrecognizedtypearetobeignored.ThissectiondefinesselectDTSExpansionBoxes.
5.7.1.3.1 ExtendedParametersbox TheExtendedParametersboxcontainsadditionalmetadatainanextensiblemanner.Ifpresent,theExtendedParametersboxexistsintheExpansionBoxdescribedintheprecedingsection.class ExtendedParameters extends FullBox (‘epba’, version = 0, 0) { bit(1) ChannelLayoutExtFlag; // 0 = no ChannelLayoutExt, 1 = present bit(7) ReservedFlags; // shall be set to 0; if (ChannelLayoutExtFlag == 1) { bit(16) ChannelLayoutExt; } }
5.7.1.3.1.1 Semantics
ChannelLayoutExtFlag–IfChannelLayoutExtFlagissetto1,thenChannelLayoutExtispresent. ReservedFlags–These flags are reserved for future definition and for the purposes of this
specification shall be set to 0.
ChannelLayoutExt–extensiontoChannelLayout,accordingtoTable5‐8. Table5‐8‐ChannelLayoutExt
BitMasks LoudspeakerLocationDescription NumberofChannels
0x0001 Centerbelowinfront 1
0x0002 Left/Rightbelowinfront 2
0x0004–0x8000 Reserved
5.7.2 Restrictions on DTS Formats
ThissectiondescribestherestrictionsthatSHALLbeappliedtotheDTSformatsencapsulatedinaDCC.
5.7.2.1 Generalconstraints
ThefollowingconditionsSHALLNOTchangeinaDTSaudiostreamoraCoresubstream: DurationofSynchronizedFrame BitRate SamplingFrequency AudioChannelArrangement LowFrequencyEffectsflag Extensionassignment
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ThefollowingconditionsSHALLNOTchangeinanExtensionsubstream: DurationofSynchronizedFrame SamplingFrequency AudioChannelArrangement LowFrequencyEffectsflag Embeddedstereoflag ExtensionsassignmentdefinedinStreamConstruction
5.7.2.2 MaximumBitrate
ThemaximumbitrateofDTSelementarystreamsSHALLbecalculatedfromasingleaudioframe(onesample),bydividingthesizeinbitsofthelargestsamplebythetimedurationofthatsample.Note:maximumbitrateisrepresentedintheDTSSampleEntryasmaxBitrate.Thisisa32‐bitintegervaluerepresentedinbits/secondandiscalculatedonlyfromtheaudioelementarystream,excludinganyandallotherISOBMFFconstructions.Thevalueiscalculatedusingfloatingpointarithmeticandanyfractionalremainderinthecalculationisroundeduptotheintegerportionoftheresultandthatintegerisusedtorepresentthevalue.
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6 SubtitleElementaryStreams
6.1 Overview
ThischapterdefinestheCFFsubtitleelementarystreamformat,howitisstoredinaDCCasatrack,andhowitissynchronizedandpresentedincombinationwithvideo.Theterm“subtitle”inthisdocumentisusedtomeanavisualpresentationthatisprovidedsynchronizedwithvideoandaudiotracks.Subtitlesarepresentedforvariouspurposesincludingdialoglanguagetranslation,contentdescription,“closedcaptions”fordeafandhardofhearing,andotherpurposes.Subtitletracksaredefinedwithanewmediatypeandmediahandler,comparabletoaudioandvideomediatypesandhandlers.Subtitletracksuseasimilarmethodtostoreandaccesstimed“samples”thatspandurationsontheMovietimelineandsynchronizewithothertracksselectedforpresentationonthattimelineusingthebasicmediatracksynchronizationmethodofISOBaseMediaFileFormat.CFFsubtitlesaredefinedusingtheTimedTextMarkupLanguage(TTML),asdefinedbythe[SMPTE‐TT]standard,whichisderivedfromtheW3C“TimedTextMarkupLanguage”[W3C‐TT]standard.Withthisapproach,[SMPTE‐TT]XMLdocumentscontrolthepresentationofsubtitlesduringtheirsampleduration,analogoustothewayanISOmediafileaudiosamplecontainsasyncframeoraccessunitofaudiosamplesandpresentationinformationspecifictoeachaudiocodecthatcontrolthedecodingandpresentationofthecontainedaudiosamplesduringthelongerdurationoftheISOmediafilesample.The[W3C‐TT]standardisanXMLmarkuplanguageprimarilydesignedforthepresentationandinterchangeofcharactercodedtextusingfontsets(textsubtitles).The[SMPTE‐TT]standardextendsthe[W3C‐TT]standardtosupportthepresentationofstoredbitmappedimages(imagesubtitles)andtosupportthestorageofdatastreamsforlegacysubtitleandcaptionformats(e.g.CEA‐608).Textandimagesubtitleseachhaveadvantagesforsubtitlestorageandpresentation,soitisusefultohaveonecommonsubtitlingformatthatiscapableofprovidingeitheratextsubtitlestreamoranimagesubtitlestream.Advantagesoftextsubtitlinginclude:
Textsubtitlesrequireminimalsizeandbandwidth
Devicescanpresenttextsubtitleswithdifferentstyles,sizes,andlayoutsfordifferentdisplays,viewing
conditionsanduserpreferences
Textsubtitlescanbeconvertedtospeechandtactilereadouts(forvisuallyimpaired)\
Textsubtitlesaresearchable
Advantagesofimagesubtitlinginclude:
Imagesubtitlesenablepublisherstofullycontrolpresentationofcharacters(includingglyphs,characterlayout,size,overlayetc.)
Imagesubtitlesenablepublisherstoaddgraphicalelementsandeffectstopresentation
Imagesubtitlesprovideaconsistentsubtitlingpresentationacrossallplaybackenvironments
CFFsubtitletrackscanbeeithertextsubtitletracksorimagesubtitletracks,i.e.themixingoftextandimagesubtitleswithinonetrackisnotsupported.
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Inordertooptimizestreaming,progressiveplayback,andrandomaccessusernavigationofvideoandsubtitles,[ISOTEXT]andthisspecificationdefinehow[SMPTE‐TT]documentsarestoredasmultipledocumentsinanISOBaseMediaTrackandhow,inthecaseofanimagesubtitletrack,associatedimagefilesarestoredasmultiplefilesinanISOBaseMediaTrack.ImagefilesarestoredseparatelyasItemsineachsampleandreferencedfromanadjacent[SMPTE‐TT]documentinordertolimitthemaximumsizeofeachdocument,whichwilldecreasedownloadtimeandplayermemoryrequirements.
6.2 CFF‐TTFormat
6.2.1 Definition
CFF‐TTdocumentsSHALLconformtotheSMPTETimedTextspecification[SMPTE‐TT],withtheadditionalconstraintsdefinedinthisspecification.
6.2.2 CFF‐TT Text Encoding
CFF‐TTdocumentsSHALLuseUTF‐8characterencodingasspecifiedin[UNICODE].AllUnicodeCodePointscontainedwithinCFF‐TTdocumentsSHALLbeinterpretedasdefinedin[UNICODE].
6.2.3 CFF TimedText Profiles
The[SMPTE‐TT]formatprovidesameansforspecifyingacollectionofmandatoryandoptionalfeaturesandextensionsthatmustormightbesupported.ThiscollectionisreferredtoasaTimedTextProfile.Inordertofacilitateinteroperability,thisspecificationdefinestheCFFTimedTextProfilesderivedfromtheSMPTETTProfiledefinedin[SMPTE‐TT].TwoTimedTextProfilesaredefinedbythisspecification–textandimage.CFF‐TTdocumentsSHALLconformtoeitherthetextprofile(seeSection6.2.2.4)orimageprofile(seeSection6.2.2.5).NotethatthemixingoftextandimagesubtitleswithinoneCFF‐TTdocumentisnotsupported.
6.2.3.1 CFFTTMLExtension–forcedDisplayMode
6.2.3.1.1 DefinitionTheforcedDisplayModeTTMLextensionisdefinedtosupportthesignalingofablockofsubtitlecontentthatisidentifiedas“Forced”subtitlecontent.“Forced”subtitlecontentissubtitlecontentthatrepresentsaudio(e.g.foreignlanguage)ortext(e.g.asign)thatisnottranslatedintheaudio/videopresentation.
6.2.3.1.2 XMLNamespacehttp://www.decellc.org/schema/2012/01/cff‐tt‐metaTherecommendedprefixforthisnamespaceis“cff:”.
6.2.3.1.3 XMLDefinition
Values: false|true
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Initial: false
Appliesto: body,div,p,region,span
Inherited: yes
Percentages: N/A
Animatable: discreteNote:AlthoughtheforcedDisplayModeattribute,likealltheTTMLstyleattributes,hasnodefinedsemanticsona<br>contentelement,forcedDisplayModewillapplytoa<br>contentelementifitiseitherdefinedonanancestorcontentelementofthe<br>contentelementoritisappliedtoaregionelementcorrespondingtoaregionthatthe<br>contentelementisbeingflowedinto.TheforcedDisplayModeTTMLextensionisanxs:Booleandatatypeattribute.
6.2.3.1.4 XMLSchemaDocumentURIreference:cff-tt-meta-{DMEDIA_VERSION_POINTS}.xsdNotes:
{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexA. InanycasewheretheXMLschemadocumentconflictswiththisspecification,thisspecificationis
authoritative. URIisdefinedin[RFC3986]
6.2.3.1.5 XMLExampleSnippet<div> <p region="subtitle1" begin="00:05:00" end="00:05:15" cff:forcedDisplayMode="true"> This subtitle is forced. </p> </div>
6.2.3.1.6 LayoutandFlowWhenonly“Forced”subtitlecontentisdisplayed,contentnotsignaledforcedDisplayMode=”true”SHALLbehiddenbutusedforlayoutandflowi.e.thiscontentwillbeequivalentto
tts:visibility=”hidden”.Notethatsettingtts:visibility=”hidden”onallelementswithinaregionwillleavetheregionvisibleifithastts:showBackground=”always”(thedefault).
6.2.3.2 CFFTTMLExtension–progressivelyDecodable
6.2.3.2.1 DefinitionTheprogressivelyDecodableTTMLextensionisdefinedtosupportthesignalingofwhetherthedocumentcanbeprogressivelydecoded.Whensettotrue,thisextensionsignalsthatthedocumenthas
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beendesignedtobeprogressivelydecodablebyadecoder.Adocumentthatincludesattp:progressivelyDecodableattributewithvalue"true"onthe<tt>elementSHALLconformtothefollowing:
1. noattributeorelementoftheTTMLtimingvocabularySHALLbepresentwithinthe<head>element;and
2. giventwoIntermediateSynchronicDocumentsAandBwithpresentationtimesTAandTB,respectively,TASHALLNOTbegreaterthanTBifAmapstoa<p>elementthatoccursearlierinthedocumentthanany<p>elementtowhichBmaps;and
3. childelementsof<p>SHALLNOThaveanattributeoftheTTMLtimingvocabulary;and4. noelementSHALLreferenceanotherelementthatoccursafteritinthedocument.
Notes: Elementswithidenticalresolvedbegintimesneedtobeintheorderdesiredforflow.
6.2.3.2.2 XMLNamespacehttp://www.decellc.org/schema/2012/01/cff‐tt‐metaTherecommendedprefixforthisnamespaceis“cff:”.
6.2.3.2.3 XMLDefinition
Values: false|true
Initial: false
Appliesto: tt
Inherited: no
Percentages: N/A
Animatable: N/ATheprogressivelyDecodableTTMLextensionisanxs:Booleandatatypeattribute.
6.2.3.2.4 XMLSchemaDocumentURIreference:cff-tt-meta-{DMEDIA_VERSION_POINTS}.xsdNotes:
{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE. InanycasewheretheXMLschemadocumentconflictswiththisspecification,thisspecificationis
authoritative. URIisdefinedin[RFC3986]
6.2.3.2.5 XMLExampleSnippet<tt xmlns="http://www.w3.org/ns/ttml" xmlns:ttm="http://www.w3.org/ns/ttml#metadata" xmlns:tts="http://www.w3.org/ns/ttml#styling"
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xmlns:ttp="http://www.w3.org/ns/ttml#parameter" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:cff="http://www.decellc.org/schema/2012/01/cff-tt-meta" xsi:schemaLocation="http://www.w3.org/ns/ttml cff-tt-text-ttaf1-dfxp-{DMEDIA_VERSION_POINTS}.xsd http://www.decellc.org/schema/2012/01/cff-tt-meta cff-tt-meta-{DMEDIA_VERSION_POINTS}.xsd" xml:lang="es" ttp:frameRate="24" ttp:frameRateMultiplier="1000 1001" ttp:timeBase="media" cff:progressivelyDecodable=”true” >
Note: {DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.
6.2.3.3 GeneralProfileRestrictions
6.2.3.3.1 FeatureRestrictionsThefollowingTTMLrestrictionsSHALLapplytoallCFFTimedTextdocuments.
Table6‐1–CFFGeneralTTMLFeatureRestrictionsFEATURE CONSTRAINT#cellResolution SHALLNOTbeused.#clockMode SHALLNOTbeused.
#color Note:Asrequiredin[SMPTE‐TT],theinitialvalueoftts:coloris"white".
#dropMode SHALLNOTbeused.
#extent-region
•ThemaximumsizeSHALLbespecifiedandSHALLbesmallerthanorequaltotherootcontainer.•regionspresentedinthesameSubtitleEventSHALLNOToverlap(seeSection6.6foradefinitionof“SubtitleEvent”andSection6.2.2.3.2foradefinitionofwhenaregionis“presented”).
#extent-root
tts:extentSHALLNOTbespecifiedonthe<tt>elementiftrack_size_is_aspect_ratioissetintheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’),oreitherthewidthorheightvaluesintheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’)aresetto0.Ifunitofmeasurepx(pixel)lengthvaluesareusedintheCFF‐TTdocument,thentts:extentSHALLbepresentonthe<tt>element.
Iftts:extentisspecifiedonthe<tt>element,itSHALLbeequaltothewidthandheightvaluesintheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’).
Iftts:extentisnotspecifiedonthe<tt>element,thespatialextentoftherootcontainerisdeterminedperSection6.2.4.
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#frameRate
•Ifspecified,ttp:frameRateandttp:frameRateMultiplierattributesSHALLcollectivelymatchtheframerateoftheassociatedvideotrack.•Ifnotspecified,theframerateSHALLbetheframerateoftheassociatedvideotrack.
#frameRateMultiplier
•Ifspecified,ttp:frameRateandttp:frameRateMultiplierattributesSHALLcollectivelymatchtheframerateoftheassociatedvideotrack.•Ifnotspecified,theframerateSHALLbetheframerateoftheassociatedvideotrack.
#length Theunitofmeasurepx(pixel)SHALLbethesameunitofmeasureasthatusedfortheassociatedvideotrack.
#length-cell SHALLNOTbeused.#length-negative SHALLNOTbeused.
#length-percentage
The“pixel”valueequatedwithany"percentage"lengthvalueSHALLbeapixelontheCFF‐TTCoordinateSystem.Tocalculatethepixel,the“roundtonearest”roundingalgorithmSHALLbeutilizedwiththe“roundhalf‐up”tiebreakruleapplied.Note:seeSection6.2.3formoredetailsontheCFF‐TTCoordinateSystem.
#markerMode SHALLNOTbeused.
#origin
•regionsSHALLbecontainedwithintherootcontainer.•regionspresentedinthesameSubtitleEventSHALLNOToverlap(seeSection6.6foradefinitionof“SubtitleEvent”andSection6.2.2.3.2foradefinitionofwhenaregionis“presented”).Note:perthe#length‐cellrestrictiondefinedabove,itisprohibitedtouse"c"(cell)scalarunitrepresentations.
#overflow SHALLNOTbeused.#pixelAspectRatio SHALLNOTbeused#subFrameRate SHALLNOTbeused.
#tickRate
ifspecified,ttp:tickRateSHALLbesettothesamevalueasthatofthetimescaleparameterinthesubtitletrack'sMediaHeaderBox(‘mdhd’).if#time-offset-with-ticksexpressionstimeExpressionvaluesareusedintheCFF‐TTdocument,ttp:tickRateSHALLbepresentonthe<tt> elementandcomplywiththeconstraintdefinedabove.
#timeBase-clock SHALLNOTbeused.
#timeBase-media
timeBase SHALLbe“media”wheretimezeroisthestartofthesubtitletrackdecodetimeonthemediatimeline.Notethattimezerodoesnotresetwitheverysubtitlefragmentandmediatimeisaccumulatedacrosssubtitlefragments.
#timeBase-smpte SHALLNOTbeused.
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#timing
•Thesamesyntax(clock-timeoroffset-time)SHOULDbeusedthroughouttheCFF‐TTdocument.•OffsettimeexpressionsusingthetickmetricSHOULDNOTusefractionalticks.•ExplicitlydefinedtimingSHALLNOTextendbeyondthetimespanoftheCFF‐TTdocument’ssubtitlesampleontheISOmediatimeline.Note:#time-offset-with-framesexpressionsaretranslatedtomediatimewiththefollowingequation(whereMisthemediatimeinseconds):M 60 hours 60 minutes seconds
frames
ttp: frameRateMultiplier ttp: frameRate
Note:#time-offset-with-ticksexpressionsarecalculatedfrommediatimewiththefollowingequation(whereMisthemediatimeinseconds):Tick ceiling M ttp: tickRate
6.2.3.3.2 ElementRestrictionsThefollowingTTMLrestrictionsSHALLapplytoallCFFTimedTextdocuments.
Table6‐2–CFFGeneralTTMLElementRestrictionsELEMENT CONSTRAINT
body AllcontentpresentedinaSubtitleEventSHALLbeassociatedwithaDocumentInstancecontentregioni.e.suchcontentSHALLNOTbedirectlyplacedintheRootContainerRegion.
region
NumberofregionspresentedinthesameSubtitleEventSHALLbe<=4(seeSection6.6foradefinitionofSubtitleEvent).AregionSHALLbeconsidered“presented”ifallfourofthefollowingaretrue:1)Theregiondoesnothaveatts:opacity="0.0"(notethat“1.0”isthedefaultvalueofthetts:opacityattribute);and2)Theregiondoesnothaveatts:visibility="hidden"(notethat“visible”isthedefaultvalueofthetts:visibilityattribute);and3)Theregiondoesnothaveatts:display="none"(notethat"auto"isthedefaultvalueofthetts:displayattribute);and4)contentisselectedintotheregionatthetimeoftheSubtitleEvent,ortheregionhasatts:showBackground=“always”andatts:backgroundColorwithnon‐transparentalpha(notethat“always”isthedefaultvalueofthetts:showBackgroundattribute).
ttThe<tt>elementSHALLincludeanxmlnsattributewithorwithoutaprefix)with“http://www.w3.org/ns/ttml”
6.2.3.3.3 AttributeRestrictionsThefollowingTTMLrestrictionsSHALLapplytoallCFFTimedTextdocuments.
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Table6‐3–GeneralTTMLAttributeRestrictionsELEMENT CONSTRAINT
xml:lang
Ifspecified,thexml:langattributeSHALLmatchtheSubtitle/LanguageMulti‐TrackRequiredMetadata(seeSection2.1.2.1)ifMulti‐TrackRequiredMetadataispresentintheDCC.Note:xml:langMAYbesettoanemptystring.
6.2.3.4 TextSubtitleProfile
6.2.3.4.1 XMLSchemaDocumentURIreference:“cff-tt-text-ttaf1-dfxp-{DMEDIA_VERSION_POINTS}.xsd” Notes:
{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.Note:InanycasewheretheXMLschemadocumentconflictswiththisspecification,thisspecificationisauthoritative.
URIisdefinedin[RFC3986]
6.2.3.4.2 xsi:schemaLocationCFFTimedTextdocumentscontainedwithinatextsubtitletrackSHOULDhaveanxsi:schemaLocationattributedefinedonthe<tt>element.Thevalueofthisxsi:schemaLocationattributeistobesetasfollows:
“http://www.w3.org/ns/ttmlcff‐tt‐text‐ttaf1‐dfxp‐{DMEDIA_VERSION_POINTS}.xsd”SHOULDbeincluded.
IftheforcedDisplayModeextensiondefinedinSection6.2.2.1ortheprogressivelyDecodableextensiondefinedinSection6.2.2.2isusedinthedocument,“http://www.decellc.org/schema/2012/01/cff‐tt‐metacff‐tt‐meta‐{DMEDIA_VERSION_POINTS}.xsd”SHOULDbeincluded.
Thebuilt‐inXMLSchemanamespaces“http://www.w3.org/2001/XMLSchema”and“http://www.w3.org/2001/XMLSchema‐instance”andanynamespacedeclarationwhichhasaprefixbeginningwiththethree‐lettersequence"xml"SHOULDNOTbeincluded.
AllotherschemasforallthenamespacesdeclaredinthedocumentSHOULDbeincludedwiththefollowingexception:ifaschemadefinesmultiplenamespaces,itSHOULDonlybepresentinthexsi:schemaLocationonce(forexample,only...ns/ttmlisrecommendedtobeincluded,notboth...ns/ttmland...ns/ttml#style).
Note:{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.
6.2.3.4.3 FeaturerestrictionsInadditiontotherestrictionsdefinedinSection6.2.2.3.1,thefollowingrestrictionsSHALLapplytoCFFTimedTextdocumentscontainedwithinatextsubtitletrack.
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Table6‐4‐CFFTextSubtitleTTMLFeatureRestrictionsFEATURE CONSTRAINT
#extent-region
•lengthexpressionsSHALLuse"px"(pixel)scalarunitsor"percentage"representation."em"(typographyunitofmeasure)SHALLNOTbeused.Note:perthe#length‐cellrestrictiondefinedinTable61‐,itisprohibitedtouse"c"(cell)scalarunitrepresentations.•SHOULDbelargeenoughfortextcontentlayoutwithoutclippinginaccordancewiththeHypotheticalRenderModeldefinedinSection6.6.4.2.
#fontFamily •Atts:fontFamilyofeither“monospaceSerif”or“proportionalSansSerif”SHOULDbespecifiedforallpresentedtextcontent.•Atts:fontFamilyof“default”SHALLbeequivalentto“monospaceSerif”.
#fontSize-anamorphic
SHALLNOTbeused.
#origin
"em"(typographyunitofmeasure)SHALLNOTbeused.Note:perthe#length‐cellrestrictiondefinedabove,itisprohibitedtouse"c"(cell)scalarunitrepresentations.
#profile
AdocumentSHALLcontainattp:profileelementunderthe<head>element,wheretheuseattributeofthatelementisspecified“http://www.decellc.org/profile/cff‐tt‐text‐{DMEDIA_VERSION_POINTS}”.Note:{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.
#textOutline Ifspecified,theborderthicknessSHALLbe10%orlessthantheassociatedfontsize.
#textOutline-blurred
SHALLNOTbeused.
6.2.3.4.4 SMPTEExtensionRestrictionsInadditiontotherestrictionsdefinedinSection6.2.2.3.1,thefollowingrestrictionsSHALLapplytoCFFTimedTextdocumentscontainedwithinantextsubtitletrack.
Table6‐5‐CFFTextSubtitleTTMLSMPTEExtensionRestrictionsEXTENSION CONSTRAINT#backgroundImage SHALLNOTbeused.#backgroundImageHorizontal SHALLNOTbeused.#backgroundImageVertical SHALLNOTbeused.#image SHALLNOTbeused.
6.2.3.5 ImageSubtitleProfile
6.2.3.5.1 XMLSchemaDocumentURIreference:“cff-tt-image-ttaf1-dfxp-{DMEDIA_VERSION_POINTS}.xsd”URIreference:“cff-tt-image-smpte-tt-{DMEDIA_VERSION_POINTS}.xsd”
Notes: {DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE. InanycasewheretheXMLschemadocumentconflictswiththisspecification,thisspecificationis
authoritative. URIisdefinedin[RFC3986]
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6.2.3.5.2 xsi:schemaLocationCFFTimedTextdocumentscontainedwithinanimagesubtitletrackSHOULDhavean‘xsi:schemaLocation’attributedefinedonthe‘<tt>’element.Thevalueofthisxsi:schemaLocationattributeistobesetasfollows:
“http://www.w3.org/ns/ttmlcff‐tt‐image‐ttaf1‐dfxp‐{DMEDIA_VERSION_POINTS}.xsd”andhttp://www.smpte‐ra.org/schemas/2052‐1/2010/smpte‐ttcff‐tt‐image‐smpte‐tt‐{DMEDIA_VERSION_POINTS}.xsd”SHOULDbeincluded.
IftheforcedDisplayModeextensiondefinedinSection6.2.2.1ortheprogressivelyDecodableextensiondefinedinSection6.2.2.2isusedinthedocument,“http://www.decellc.org/schema/2012/01/cff‐tt‐metacff‐tt‐meta‐{DMEDIA_VERSION_POINTS}.xsd”SHOULDbeincluded.
Thebuilt‐inXMLSchemanamespaces“http://www.w3.org/2001/XMLSchema”and“http://www.w3.org/2001/XMLSchema‐instance”andanynamespacedeclarationwhichhasaprefixbeginningwiththethree‐lettersequence"xml"SHOULDNOTbeincluded.
AllotherschemasforallthenamespacesdeclaredinthedocumentSHOULDbeincludedwiththefollowingexception:ifaschemadefinesmultiplenamespaces,itSHOULDonlybepresentinthexsi:schemaLocationonce(forexample,only...ns/ttmlisrecommendedtobeincluded,notboth...ns/ttmland...ns/ttml#style).
Note:{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.
6.2.3.5.3 FeatureRestrictionsInadditiontotherestrictionsdefinedinSection6.2.2.3.1,thefollowingrestrictionsSHALLapplytoCFFTimedTextdocumentscontainedwithinanimagesubtitletrack.
Table6‐6‐CFFImageSubtitleTTMLFeatureRestrictionsFEATURE CONSTRAINT#bidi SHALLNOTbeused.#color SHALLNOTbeused.
#content <p>,<span>,<br>SHALLNOTbeused.#direction SHALLNOTbeused.#displayAlign SHALLNOTbeused.#fontFamily SHALLNOTbeused.#fontSize SHALLNOTbeused.#fontStyle SHALLNOTbeused.#fontWeight SHALLNOTbeused.#length-em SHALLNOTbeused.#lineBreak-uax14 SHALLNOTbeused.#lineHeight SHALLNOTbeused.#nested-div SHALLNOTbeused.#nested-span SHALLNOTbeused.#padding SHALLNOTbeused.
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#profile
AdocumentSHALLcontainattp:profileelementwheretheuseattributeofthatelementisspecified“http://www.decellc.org/profile/cff‐tt‐image‐{DMEDIA_VERSION_POINTS}”.Note:{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.
#textAlign SHALLNOTbeused.#textDecoration SHALLNOTbeused.#textOutline SHALLNOTbeused.#wrapOption SHALLNOTbeused.#writingMode-vertical SHALLNOTbeused.
6.2.3.5.4 ElementRestrictionsInadditiontotherestrictionsdefinedinSection6.2.2.3.1,thefollowingrestrictionsSHALLapplytoCFFTimedTextdocumentscontainedwithinanimagesubtitletrack.
Table6‐7–CFFImageSubtitleTTMLElementRestrictionsELEMENT CONSTRAINT
div
Ifasmpte:backgroundImageattributeisappliedtoa<div>,thewidthandheightoftheregionextentassociatedwiththe<div>SHALLequatetothewidthandheightoftheimagesourcereferencedbythesmpte:backgroundImage.Note:seethe#length‐percentageconstraintinTable61‐formoreinformationonequatinga"percentage"lengthrepresentationofaregiontopixelsintheimagesourcereferencedbythesmpte:backgroundImage.
region
ForeachSubtitleEvent,thereSHALLbeatmostone<div>withthesmpte:backgroundImageattributeappliedassociatedwithany“presented”region(seeSection6.6foradefinitionof“SubtitleEvent”andSection6.2.2.3.2foradefinitionofwhenaregionis“presented).
6.2.3.5.5 SMPTEExtensionRestrictionsInadditiontotherestrictionsdefinedinSection6.2.2.3.1,thefollowingTTMLrestrictionsSHALLapplytoCFFTimedTextdocumentscontainedwithinanimagesubtitletrack.
Table6‐8‐CFFImageSubtitleTTMLSMPTEExtensionRestrictionsEXTENSION CONSTRAINT
#backgroundImageHorizontal SHALLNOTbeused.Note:thesmpte:backgroundImage attribute remainsavailableforuse.
#backgroundImageVertical SHALLNOTbeused.Note:thesmpte:backgroundImage attribute remainsavailableforuse.
#image <smpte:image> SHALLNOTbeused.
6.2.4 CFF‐TT Coordinate Plane
TheCFF‐TTrootcontaineroriginSHALLbe"00".
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TheCFF‐TTrootcontainerspatialextentisdeterminedbasedonfieldvalueswithintheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’)asfollows:
1. widthandheightaresettonon‐zerovalues,andtrack_size_is_aspect_ratioisnotused:thespatialextentoftheCFF‐TTrootcontainerissettotheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’)widthandheightvaluesper[ISOTEXT];
2. widthandheightaresettonon‐zerovalues,andtrack_size_is_aspect_ratioisused:thespatialextentoftheCFF‐TTrootcontainerSHALLbesettothewidthandheightoftheassociatedvideotrack;
3. widthandheightaresettozerovalues:thespatialextentoftheCFF‐TTrootcontainerSHALLbesettothewidthandheightoftheassociatedvideotrack.
Notes: PerSection6.2.3.3.1:iftts:extentisspecifiedonthe<tt>element,itmustequalthewidthand
heightvaluesintheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’);andifunitofmeasurepx(pixel)lengthvaluesareusedintheCFF‐TTdocument,thentts:extentmustbepresentonthe<tt>element.
ThevaluesoftheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’)arenormativelyconstrainedinSection6.7.2,includingarequirementthatifaspectratioisdefinedbytheCFF‐TTtrack’sTrackHeaderBox(‘tkhd’),itmustmatchtheaspectratiooftheassociatedvideotrack.
Thematrixvaluesinthevideoandsubtitletrackheadersarethedefaultvalue.Thepositionofthesubtitledisplayregionisdeterminedonthenotional‘square’(uniform)griddefinedbytherootcontainerextent.Thedisplayregion‘tts:origin’valuesdeterminetheposition,andthe‘tts:extent’valuesdeterminethesizeoftheregion.Figure61‐illustratesanexampleofthesubtitledisplayregionposition.Note:Subtitlescanonlybeplacedwithintheencodedvideoactivepicturearea.Ifsubtitlesneedtobeplacedoverblackmattingareas,theadditionalmattingareasneedtobeconsideredanintegralpartofthevideoencodingandincludedwithinthevideoactivepictureareaforencoding.
Figure6‐1–Exampleofsubtitledisplayregionposition
InFigure61‐,theparametersaredenotedasfollows:
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Vw,Vh–Videotrackheaderwidthandheight,respectively. [ISO]co‐ordinateorigin‐theoriginoftheCFF‐TTrootcontainer. Sw,Sh–Subtitletrackwidthandheight,respectivelywhichisalsothespatialextentoftheCFF‐TT
rootcontainer. Ew,Eh–CFF‐TTdisplayregion‘tts:extent’.
Ox,Oy–CFF‐TTdisplayregion‘tts:origin’. Regionarea–areadefinedintheCFF‐TTdocumentthatsetstherenderinginwhichtextisflowed
orimagesaredrawn. Displayarea–renderingareaoftheCFF‐TTprocessor.
6.2.5 CFF‐TT External Time Interval
TheCFF‐TTDocument'sExternalTimeIntervalSHALLequalthedurationofthesubtitletrackontheISOmediatimeline.Theexternaltimeintervalisthetemporalbeginningandendingofadocumentinstanceasspecifiedin[W3C‐TT]andincorporatedin[SMPTE‐TT].
6.3 CFF‐TTSubtitleEventandVideoFrameSynchronization
CFF‐TTisdesignedtosynchronizewithvideoatthevideoframelevel‐thatis,SubtitleEvents(seeSection6.6)willfirstbedisplayedonaspecificframeofvideoonthevideoframegridandwillberemovedonaspecificframeofvideoonthevideoframegrid.Thefollowingequationisusedtocalculatethevideoframerepresentedbyamediatimevaluecalculatedfroma‘<timeExpression>’valueinaCFF‐TTdocument(whereMisthemediatimeinseconds):
F ceiling M ttp: frameRateMultiplier ttp: frameRate InordertodeterminethevideoframewithwhichaSubtitleEventisactuallyfirstdisplayedorremovedfroma‘<timeExpression>’valueinaCFF‐TTdocument,thevideoframeSHALLbecalculatedfromthe‘<timeExpression>’valueandthetimingmodeldefinedinSection6.6.2SHALLbeapplied.Note:Section6.2.2.3requiresthatthevalueof‘ttp:frameRate’isthatofthevideotrack(andifsetinthedocumentitisrequiredtobeequaltothevideotrackframerate).
6.4 CFF‐TTEncodedImageFormat
ImagesSHALLconformtoPNGimagecodingasdefinedinSections7.1.1.3and15.1of[MHP],withthefollowingadditionalconstraints:
PNGimagesSHALLNOTberequiredtocarryapHYschunkindicatingpixelaspectratioofthebitmap.Ifpresent,thepHYschunkSHALLindicatesquarepixels.
Note:Ifnopixelaspectratioiscarried,thedefaultofsquarepixelswillbeassumed.
6.5 CFF‐TTStructure
6.5.1 Track Format
ACFFsubtitletrackiseitheratextsubtitletrackoranimagesubtitletrack.
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TextsubtitletracksSHALLcontainoneormoreCFF‐TTXMLdocumentsallofwhicharecompliantwithSection6.2.2.4.TextsubtitletracksSHALLNOTcontainanyimagedata.TextsubtitletracksSHALLcomplywith[ISOTEXT].ImagesubtitletracksSHALLcontainoneormoreCFF‐TTXMLdocuments,allofwhicharecompliantwithSection6.2.2.5.CFF‐TTdocumentsinimagesubtitletracksSHALLincorporateimagesintheirpresentationbyreferenceonlyandimagesarenotconsideredwithinthedocumentsizelimit.Inthiscase,referencedimagesSHALLbestoredinthesamesampleasthedocumentthatreferencesthemandSHALLNOTexceedthemaximumsizesspecifiedininTable69‐.ImagesubtitletracksSHALLcomplywith[ISOTEXT].Note:
Per[ISOTEXT],eachCFF‐TTdocumentinaCFFsubtitletrackisstoredinasinglesubtitlesamplewhichisa“syncsample”,meaningthatitisindependentlydecodable.
“syncsample”inmoviefragmentscannotbesignaledbytheabsenceoftheSyncSamplebox(‘stss’)orbythepresenceoftheSyncSamplebox(‘stss’),sincethisboxisnotdesignedtolistsyncsamplesinmoviefragments.Instead,signalingcanbeachievedbyothermeanssuchassettingthe'sample_is_non_sync_sample'flagto"0"inthe'default_sample_flags'fieldintheTrackExtendsbox(‘trex’).
6.5.2 Sample Format
6.5.2.1 Definition
SubtitlesamplestorageSHALLcomplywith[ISOTEXT].Inimagesubtitletracks,eachsubtitlesampleSHALLalsocontainallimagesreferencedintheCFF‐TTdocumentandstorageofimagesSHALLcomplywith[ISOTEXT].EachsubtitletrackfragmentSHALLcontainexactlyonesubtitlesample.
Figure6‐2–StorageofimagesfollowingtherelatedSMPTETTdocumentinasample
6.5.2.2 Images
Imageformatsusedforsubtitles(i.e.PNG)SHALLbespecifiedinamannersuchthatallofthedatanecessarytoindependentlydecodeanimage(i.e.colorlook‐uptable,bitmap,etc.)isstoredtogetherwithinasinglesub‐sample.ThetotalsizeofimagedatastoredinasampleSHALLNOTexceedthevaluesindicatedinTable69‐.“Imagedata”SHALLincludealldatainthesampleexceptfortheCFF‐TTdocument,whichSHALLbestoredatthebeginningofeachsampletocontrolthepresentationofanyimagesinthatsample.TheCFF‐TTdocumentSHALLreferenceeachimageusingaURN,per[ISOTEXT],oftheform:urn:dece:container:subtitleimageindex:<index>.<ext> Where:
Doc Image Image Etc.
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<index>isasdefinedin[ISOTEXT]. <ext>isasdefinedin[ISOTEXT].
Note:ACFF‐TTdocumentmightreferencethesameimagemultipletimeswithinthedocument.Insuchcases,therewillbeonlyonesub‐sampleentryintheSub‐SampleInformationBox(‘subs’)forthatimage,andtheURIusedtoreferencetheimageeachtimewillbethesame.However,ifanimageisusedbymultipleCFF‐TTdocuments,thatimageisrequiredtobestoredonceineachsampleforwhichadocumentreferencesit.Anexampleofimagereferencingisshownbelow:<head> <layout> <region tts:extent="250px 50px" tts:origin="200px 800px" xml:id="r1"/> <region tts:extent="200px 50px" tts:origin="200px 800px" xml:id="r2"/> </layout> </head> <body> <div region="r1" smpte:backgroundImage="urn:dece:container:subtitleimageindex:1.png"/> <div region="r2" smpte:backgroundImage="urn:dece:container:subtitleimageindex:2.png"/> </body>
6.5.2.3 Constraints
CFF‐TTsubtitlesamplesSHALLNOTexceedthefollowingconstraints:Table6‐9–ConstraintsonSubtitleSamples
Property ConstraintCFF‐TTdocumentsize SingleXMLdocumentsize<=500x210bytes
6.6 CFF‐TTHypotheticalRenderModel
Figure6‐3–BlockDiagramofHypotheticalRenderModel
ThisSectiondefinestheCFF‐TTHypotheticalRenderModel.CFF‐TTdocumentsSHALLNOTexceedthelimitsandconstraintsdefinedbythismodel.
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6.6.1 Functional Model
ThehypotheticalrendermodelforCFF‐TTsubtitlesisshowninFigure63‐.ItincludesseparateinputbuffersD(j)andEI(j)foroneCFF‐TTdocument,andasetofimagescontainedinonesample,respectively.Eachbufferhasaminimumsizedeterminedbythemaximumdocumentandsamplesizespecified.TheDocumentObjectModel(DOM)buffers,DB(j)andDB(j‐1),storetheDOMsproducedbyparsingaCFF‐TTdocument.DOMbuffersdonothaveaspecifiedsizebecausetheamountofmemoryrequiredtostorecompileddocumentsdependsonhowmuchmemoryamediahandlerimplementationusestorepresentthem.ACFF‐TTprocessorimplementationcandetermineasufficientsizebasedondocumentsizelimitsandworst‐casecodecomplexity.ThemodelincludestwoDOMbuffersinordertoenabletheprocessingandpresentationofthecurrentlyactiveCFF‐TTdocumentinDB(j‐1)whilethenextCFF‐TTdocumentisreceivedandparsedinDB(j)inpreparationforitbecomingactive.SeeSection6.6.2formoreinformationonthetimingmodelofwhendocumentsareactiveandinactive.Forthepurposesofperformingpresentationprocessing,theactivetimedurationoftheCFF‐TTdocumentisdividedintoasequenceofSubtitleEvents.ForanygivenSubtitleEventE ,allvisiblepixelsforSubtitle
EventE arepainted.
ASubtitleEventSHALLoccurwheneverthereisanychangetosubtitlepresentation.EachSubtitleEventisassociatedwithanintermediatesynchronicdocument.[W3C‐TT]Section9.3.2,asincorporatedby[SMPTE‐TT],dictateswhenanintermediatesynchronicdocumentisconstructed.Note:Achangetosubtitlepresentationcausedbythe<set>animationelementwillresultinanewSubtitleEvent.ThePresentationCompositorretrievespresentationinformationforeachSubtitleEventfromtheapplicableDocDOM(accordingtothecurrentsubtitlefragment);presentationinformationincludespresentationtime,regionpositioning,styleinformation,etc.associatedwiththeSubtitleEvent.ThePresentationCompositorconstructsanintermediatesynchronicdocumentfortheSubtitleEvent,inaccordancewith[W3C‐TT]Section9.3.2,asincorporatedby[SMPTE‐TT],andpaintsthecorrespondingSubtitleEventintothePresentationBufferP(n).TheGlyphBuffersG(n)andG(n‐1)areusedtostorerenderedglyphsacrossSubtitleEvents,allowingglyphstobecopiedintothePresentationBufferinsteadofrendered,amorecostlyoperation.ThisenablesscenarioswherethesameglyphsareusedinmultiplesuccessiveSubtitleEvents,e.g.toconveyaCEA‐608/708‐styleroll‐up.TopaintSubtitleEventE(n),thePresentationCompositorhasaccessinGlyphBufferG(n‐1)totheglyphsusedduringSubtitleEventE(n‐1)andinGlyphBufferG(n)toallglyphsusedduringSubtitleEventE(n).OnceprocessingofaSubtitleEventiscompleted,thePresentationBufferP(n)iscopiedtoP(n‐1)andtheGlyphBufferG(n)toG(n‐1).ThePresentationBufferP(n)actsasa“backbuffer”inthemodel(the“backbuffer”isthesecondarybufferinthis“doublebuffer”model–itisusedtostoretheresultofeverypaintoperationinvolvedincreatingtheSubtitleEventbutitisnotusedforthedisplayofSubtitleEventinthismodel).ThePresentationBufferP(n‐1)storesaSubtitleEventavailablefordisplaywithvideoandactsasa“frontbuffer”inthemodel(the“frontbuffer”istheprimarybufferinthis“doublebuffer”model–itisusedforthedisplayofthecompletedSubtitleEventinthismodel).TheVideoPlanestoreseachframeofdecodedvideo.ThePresentationBuffers,P(n)andP(n‐1),havethesamehorizontalandverticalsizeastheCFF‐TTrootcontainer.TheSubtitlePlaneandVideoPlanehavethesamehorizontalandverticalsizedefinedforthevideotrack.IfthewidthorheightofthePresentationBufferdonotexactlymatchthecorrespondingdimensionsoftheassociatedvideotrack,theoutputofthe
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PresentationBufferisproportionallyscaledtothewidthandheightoftheassociatedvideotrackbeforeitiswrittenontheSubtitlePlane.Aftervideo/subtitleshavebeencomposited,theresultingimageisthenprovidedoverexternalvideointerfacesifanyand/orpresentedonanintegrateddisplay.Theaboveprovidesanoverviewofahypotheticalmodelonly.AnyCFF‐TTprocessorimplementationofthismodelisallowedaslongastheobservedpresentationbehaviorofthismodelissatisfied.Inparticular,someCFF‐TTprocessorimplementationsmightrender/paintandscaletodifferentresolutionsthantheSMPTETTrootcontainerinordertooptimizepresentationforthedisplayconnectedto(orintegratedaspartof)theCFF‐TTprocessorimplementationbutinsuchcasesCFF‐TTprocessorimplementationsarerequiredtomaintainthesamesubtitleandvideorelativeposition(regardlessofdifferencesinresolutionbetweenthedisplayandSMPTETTrootcontainer).
6.6.2 Timing Model
Although,perSection6.2.4allCFF‐TTDocumentshaveanExternalTimeIntervalequaltothesubtitletrackduration,onlyoneCFF‐TTdocumentispresentedatanyonepointintimebytherendermodel.TherendermodelpresentsaCFF‐TTdocumentonlywhentheCFF‐TTdocumentisactive.ACFF‐TTdocumentisactiveonlyduringthetimespanofitsassociatedsubtitlesampleontheISOmediatimelineandatallothertimestheCFF‐TTdocumentisinactive.ConsequentlyallpresentationdefinedintheCFF‐TTdocumentwillbeshownwhenthedocumentisactive.Anyportionofpresentationassociatedwithatimewhenthedocumentisinactivewillnotbepresentedwiththefollowingexception‐ifthedocumentbecomesinactiveduringacodedvideoframe,thepresentationwillcontinueuntilthenextnearestcodedvideoframeatwhichtimeanypresentationdefinedintheCFF‐TTdocumentwillnotbeshown.Thistimingrelationshipisdefinedin[ISOTEXT]anddepictedinFigure64‐below.Therefore,duringplaybackofasubtitletrack,attheendofasubtitlesampletheDocumentassociatedwiththesubtitlesamplewillbecomeinactiveandtheDocumentassociatedwiththenextsubtitlesample,whichisimmediatelyadjacentontheISOmediatimeline,willimmediatelybecomeactiveatthestartofthenextsubtitlesample–thussubtitlepresentationwillcontinueseamlesslyoversubtitlesamples(andfragments)ontheISOmediatimelinewithoutinterruptiontosubtitlepresentation.Note:Thetimespanofthesubtitlesamplealwaysstartsatthetimerepresentedbythesumofallprevioussubtitlesampledurationsandalwayslastsforthelengthoftimerepresentedbythesample_durationdeterminedfromthedefault_sample_durationandsample_durationfieldsassociatedwiththesubtitlesample.
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Figure6‐4–TimerelationshipbetweenCFF‐TTdocumentsandtheCFF‐TTtrackISOmediatimelineTheperformanceavailableforpaintingSubtitleEventsisboundedbyconstraintsonkeyaspectsofthemodel,e.g.drawingandrenderingrates–seeAnnexA,BandC.Wheneverapplicable,theseconstraintsarespecifiedrelativetotherootcontainerdimensions,allowingCFF‐TTDocumentstobeauthoredindependentlyofvideoresolution.ThePresentationCompositorstartspaintingpixelsforthefirstSubtitleEventintheCFF‐TTdocumentatthedecodetimeofthesubtitlefragment.IfSubtitleEventE isnotthefirstinaCFF‐TTdocument,the
PresentationCompositorstartspaintingpixelsforSubtitleEventE atthe“starttime”oftheimmediately
precedingSubtitleEventE .AlldataforSubtitleEventE ispaintedtothePresentationBufferfor
eachSubtitleEvent.ForeachSubtitleEvent,thePresentationCompositorclearsthepixelswithintherootcontainer(exceptforthefirstSubtitleEventE )andthenpaints,accordingtostackingorder,allbackgroundpixelsforeach
region,thenpaintsallpixelsforbackgroundcolorsassociatedwithtextorimagesubtitlecontentandthenpaintsthetextorimagesubtitlecontent.ThePresentationCompositorneedstocompletepaintingfortheSubtitleEventE priortothestarttimeofSubtitleEventE .Theduration,inseconds,forpaintinga
SubtitleEventinthePresentationBufferisasfollowsforanygivenSubtitleEventE withintheCFF‐TT
document:
DURATION ES
BDraw C
Where: S isthenormalizedsizeofthetotaldrawingareaforSubtitleEventE ,asdefinedbelow.
BDrawisthenormalizedbackgrounddrawingperformancefactor(seeAnnexA,B,CforthebackgrounddrawingperformancefactordefinedforeachProfile).
C istheduration,inseconds,forpaintingthetextorimagesubtitlecontentforSubtitleEvent
E .SeethedetailsdefinedinSection6.7andSection6.8below.
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Note:BDraweffectivelysetsalimitonfillingsregions‐forexample,assumingthattherootcontainerisultimatelyrenderedat19201080resolution,aBDrawof12s‐1wouldcorrespondtoafillrateof1920 1080 12/s 23.7 2 pixels/s.
ThenormalizedsizeofthetotaldrawingareaforthefirstSubtitleEventE thatistobedecodedby
theCFF‐TTprocessorimplementationfortheCFF‐TTsubtitletrackisdefinedas:
S NSIZE E . R TBG
Where: risthenumberofregionsthatarepresentedinthisSubtitleEvent.SeeSection6.2.2.3.2fora
definitionofwhenaregionisconsideredtobepresented. NSIZE E . R isequalto:
widthofR heightofR rootcontainerheight rootcontainerwidth
R isaregionthatwillbepresentedintheSubtitleEventE .
TBG isthetotalnumberof‘tts:backgroundColor’attributesassociatedwiththegiven
regionR inthisSubtitleEvent(see“Notesaboutthemodel”belowforadefinitionofwhena
‘tts:backgroundColor’attributeisassociatedwitharegioninaSubtitleEvent).Example:ForaregionR withtts:extent="250px 50px"withinarootcontainerwith
tts:extent="1920px 1080px",NSIZE E . R =0.603.
ThetotalnormalizeddrawingareaforSubtitleEventE afterpresentationofthefirstSubtitleEvent
E isdefinedas:
S CLEAR E PAINT E
Where: CLEAR E =1andcorrespondstotherootcontainerinitsentirety.
PAINT E isafunctionwhichcalculatesthenormalizedareathatistobepaintedforanyregions
thatareusedinSubtitleEventE inaccordancewiththefollowing:
PAINT E NSIZE E . R NBG
Where: risthenumberofregionsthatarepresentedinthisSubtitleEvent.SeeSection6.2.2.3.2fora
definitionofwhenaregionisconsideredtobepresented. NSIZE E . R isequalto:
widthofR heightofR rootcontainerheight rootcontainerwidth R isaregionthatwillbepresentedintheSubtitleEventE .
NBG isthetotalnumberof‘tts:backgroundColor’attributesassociatedwiththe
givenregionR inthisSubtitleEvent(see“Notesaboutthemodel”belowforadefinitionof
whena‘tts:backgroundColor’attributeisassociatedwitharegioninaSubtitleEvent).
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Atthe“starttime”ofSubtitleEventE ,thecontentofthePresentationBufferisinstantaneously
transferredtotheSubtitlePlaneandblendedwithvideoatthevideoframecorrespondingtothe“starttime”ofSubtitleEventE (orthesubsequentvideoframeifthe“starttime”doesnotalignwithaframeof
videoonthevideoframegrid).ThecontentoftheSubtitlePlaneisinstantaneouslyclearedatthevideoframecorrespondingtothe“finishtime”ofSubtitleEventE (orthesubsequentvideoframeifthe“finish
time”doesnotalignwithaframeofvideoonthevideoframegrid).Notesaboutthemodel:
ToensureconsistencyofthePresentationBuffer,anewSubtitleEventrequiresclearingoftherootcontainer.
Each‘tts:backgroundColor’attributeassociatedwitharegioninaSubtitleEventrequiresanadditionalfilloperationforallregionpixels. A‘tts:backgroundColor’attributeisassociatedwitharegioninaSubtitleEvent
whena‘tts:backgroundColor’attributeisexplicitlyspecified(eitherasanattributeintheelement,orbyreferencetoadeclaredstyle)inthefollowingcircumstances: Itisspecifiedonthe‘region’layoutelementthatdefinestheregion. Itisspecifiedona‘div’,‘p’,‘span’or‘br’contentelementthatistobe
flowedintotheregionforpresentationintheSubtitleEvent(see[W3C‐TT],asincorporatedin[SMPTE‐TT],formoredetailsonwhenacontentelementisfollowedintoaregion).
Itisspecifiedona‘set’animationelementthatistobeappliedtocontentelementsthataretobeflowedintotheregionforpresentationintheSubtitleEvent(see[W3C‐TT],asincorporatedin[SMPTE‐TT],formoredetailsonwhena‘set’animationelementisappliedtocontentelements).
Evenifaspecified‘tts:backgroundColor’isthesameasspecifiedonthenearestancestorcontentelementoranimationelement,specifyingany‘tts:backgroundColor’willrequireanadditionalfilloperationforallregionpixels.
ThePresentationCompositorretainsstateoversubtitlefragmentsi.e.whenasubtitlefragmentchangeoccursduringpresentationofaCFF‐TTsubtitletrack,thefirstSubtitleEventintheCFF‐TTdocumentassociatedwiththenewsubtitlefragmentistreatedasSubtitleEventE andthelast
SubtitleEventintheCFF‐TTdocumentassociatedwiththeprevioussubtitlefragmentistreatedasSubtitleEventE .
ItispossibleforthecontentofSubtitleEventE tobeoverwrittenintheSubtitlePlanewith
SubtitleEventE priortoSubtitleEventE beingcompositedwithvideo‐thiswouldhappen
whenthecontentofSubtitleEventE wasintheSubtitlePlanebuthadnotyetbeencomposited
withvideoasanewframeofvideohadnotyetbeenpresentedsincethe“starttime”ofSubtitleEventE ),andthe“starttime”ofSubtitleEventE occurredbeforethenewframeofvideo
waspresented.
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6.6.3 ImageSubtitles
Figure6‐5–BlockDiagramofCFF‐TTImageSubtitleHypotheticalRenderModel
ThissectiondefinestheperformancemodelappliedtoCFFimagesubtitles.Inthemodel,encodedimagesarestoredintheEncodedImageBufferE(j).TheImageDecoderdecodesencodedimagesintheEncodedImageBufferE(j)totheDecodedImageBufferDI(j)withtheimagedecodingrate(seeAnnexA,B,CfortheimagedecodingratedefinedforeachProfile).TwoDecodedImageBuffers,DI(j)andDI(j‐1),areusedinordertoallowthePresentationCompositortoprocessthecurrentlyactiveCFF‐TTdocumentinDI(j‐1)whilethenextCFF‐TTdocumentisbeingprocessedinDI(j)inpreparationforpresentation‐thisallowsimagesubtitlesreferencedbyCFF‐TTdocumentsfromtwoconsecutivesamples/fragmentstobedisplayedwithoutdelay.Notethatboththe“current”subtitlefragmentandthe“next”subtitlefragmentMAYbeacquiredanddecodedpriortopresentationtime.ThePresentationCompositorbehavesasspecifiedinSections6.6.1and6.6.2.ThePresentationCompositorpaintsallpixelsforimagestobepresentedintheSubtitleEventusingthecorrespondingrasterdataintheDecodedImageBuffer.Theduration,inseconds,forpaintingaSubtitleEventinthePresentationBufferisasfollowsforanygivenSubtitleEventE :
DURATION ES
BDrawC
Forimage‐basedCFF‐TTsubtitles,C isasfollows:
C NSIZE E . I
ICpy
Where: isthenumberofdivelementswhichhaveasmpte:backgroundImageattributethatis
associatedwitharegionwhichispresentedinSubtitleEventE .SeeSection6.2.2.3.2foradefinitionofwhenaregionisconsideredtobepresented.
NSIZE E . I isequalto:
widthofI heightofI rootcontainerheight rootcontainerwidth I isanimagesubtitlethatwillbepresentedinSubtitleEventE .
ICpyisthenormalizedimagecopyperformancefactor(seeAnnexBandCfortheimagecopyperformancefactordefinedforeachProfile).
Note:Imagedecodingperformanceisnotincludedintheaboveequationsasthemodelrequiresthattheimagesassociatedwithasubtitlefragmentaredecodedinfullintooneofthe(two)decodedimagebuffersinadvanceofthestartofthesubtitlefragmentpresentationtime.
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6.6.4 Text Subtitles
Figure6‐6–BlockDiagramofCFF‐TTTextSubtitleHypotheticalRenderModel
6.6.4.1 PerformanceModel
ForeachglyphdisplayedinSubtitleEventE(n),thePresentationCompositorwill:1) ifanidenticalglyphispresentinGlyphBufferG(n),copytheglyphfromGlyphBufferG(n)tothe
PresentationBufferP(n)usingtheGlyphCopier;or2) ifanidenticalglyphispresentinGlyphBufferG(n‐1),i.e.anidenticalglyphwaspresentinSubtitle
EventE(n‐1),copyusingtheGlyphCopiertheglyphfromGlyphBufferG(n‐1)toboththeGlyphBufferG(n)andthePresentationBufferP(n);or
3) OtherwiserenderusingtheGlyphRenderertheglyphintothePresentationBufferP(n)andGlyphBufferG(n)usingthecorrespondingstyleinformation.
TwoglyphsareidenticalifandonlyifthefollowingTTMLstylesareidentical: tts:color
tts:fontFamily
tts:fontSize
tts:fontStyle
tts:fontWeight
tts:textDecoration
tts:textOutline Figure67‐providesanexampleofPresentationCompositorbehavior.
Figure6‐7–ExampleofTextSubtitlePresentationCompositorBehavior
TheNormalizedRenderedGlyphAreaofagivenrenderedglyphisdefinedas:Normalized Rendered Glyph Area (fontSize as percentage of root container height)2
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Note:TheNormalizedRenderedGlyphAreacalculationdoesnottakeintoaccountglyphdecorations(e.g.underline),glypheffects(e.g.outline)oractualglyphaspectratio.ACFF‐TTprocessorimplementationcandetermineanactualbuffersizeneedsbasedonworst‐caseglyphsizecomplexity.TheNormalizedSizeoftheGlyphBuffersG(n)orG(n‐1)isdefinedas:Normalized Glyph Buffer Size sum of the Normalized Rendered Glyph Area of the glyphs stored in the buffer within a given time
Note:SettingamaximumGlyphBufferNormalizedSizeeffectivelysetsalimitonthetotalnumberofdistinctglyphspresentinanygivenSubtitleEventE(n).Forexample,assumingamaximumNormalizedGlyphBufferSizeof1andthedefaulttts:fontSizeof1careused,theglyph'sheightaspercentageof
rootcontainerheightis ,andthemaximumnumberofdistinctglyphsthatcanbebufferedis
1 225glyphs.Inthisexample,animplementationrenderingat1920x1080wouldneedto
allocateaglyphbuffernosmallerthan 1920 32 1080 15 225 ~1Mpixels.SeeAnnexA,B,CforGlyphBufferNormalizedSizelimitsdefinedforeachProfile.Theduration,inseconds,forpaintingaSubtitleEventinthePresentationBufferiscalculatedasfollowsforanygivenSubtitleEventE :
DURATION ES
BDrawC
Fortext‐basedCFF‐TTsubtitles,C iscalculatedasfollowsforeachSubtitleEventE(n):
C 1
RenNRGA
1GCpy
NRGA
Where: cnisthetotalnumberofglyphsrenderedintothePresentationBufferP(n)inSubtitleEventE(n). Ren isthetextrenderingperformancefactoroftheithrenderedglyphintheSubtitleEventE .
GCpyisthenormalizedglyphcopyperformancefactorforglyphsthatarecopiedtothePresentationBufferP(n)usingtheGlyphCopier.
NRGA andNRGA aretheNormalizedRenderedGlyphAreaoftheithrenderedglyphandjthcopied
glyph,respectively. isthetotalnumberofcopiedglyphstothePresentationBufferP(n)usingtheGlyphCopierin
SubtitleEventE(n).TheC calculationSHALLincludeonlyglyphsinregionelementspresentedintheSubtitleEventE –see
Section6.2.2.3.2foradefinitionofwhenaregionisconsideredtobepresented.TheC calculationSHALLNOTincludeacharacter(UnicodeCodePoint)ifitdoesnotresultinachangeto
presentation(e.g.theCodePointisignoredbytheCFF‐TTProcessor).SeeAnnexA,B,CforthedefinitionofRenandGCpyforeachProfile.Note:GCpyeffectivelysetsalimitonanimatingglyphs.Forexample,assumingthattherootcontainerisultimatelyrenderedat19201080resolutionandnoregionsneedtohavebackgroundcolorpainted(soonlyaCLEAR E operationisrequiredforthenormalizeddrawingareafortheSubtitleEvent),aGCpy
andBDrawof12s‐1wouldmeanthatagroupof160glyphswithatts:fontSizeequalto5%ofthe
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rootcontainerheightcouldbemovedatmostapproximately12 1 160 0.05 8.6timespersecond.Note:Ren effectivelysetsalimitontheglyphrenderingrate.Forexample,assumingthattherootcontainerisultimatelyrenderedata19201080resolution,aRen of1.2s‐1wouldmeanthatatmost120glyphswithafontSizeof108px(10%of1080pxandNGRA=0.01)couldberenderedeverysecond.
6.6.4.2 TextLayoutModel
Properregionsize,glyphsizingandglyphlayoutwillavoidclippingoftextcontent.Thewidthofaregionisindicatedbythetts:extent<length>parameterassociatedwithwidth.Thewidthofrenderedcharactersdependsonthewidthofindividualglyphsandthespacingbetweentheglyphs(kerning).Asthisparticulartoeachfont,thelayoutmodelassumesparticularreferencefontfamiliesasdefinedinAnnexD.3;fontsthatare‘metriccompatible’canbesubstituted(afontis‘metriccompatible’ifitdoesnotchangetextflow,althoughappearancemaybedifferent).GlyphspaintedintothePresentationBufferSHALLbelaidouthorizontallywiththefollowingparameters:
Behaviorisdefinedfortwofontfamilies(tts:fontFamily): “monospaceSerif” “proportionalSansSerif”
Iftextcontenthasa“monospaceSerif”or“proportionalSansSerif”tts:fontFamilyapplied,widthandspacing(kerning)isconsistentwiththeReferenceFontFamilyforthegiventts:fontFamily.
TheReferenceFontFamilyforagivensubtitlelanguageisdefinedinAnnexD.3. Notes:
Toguaranteethattextcontentflowedintoaregionrenderswithoutclipping,itisnecessaryforthetts:extent<length>(width)parametertobeatleastthesumeachglyphonthelineanditsassociatedspacing(kerning).Insufficient<length>moretypicallyresultsinverticalclippingastextflowmovessometexttounanticipatedadditionallines.
Theheightoftheregionisspecifiedbythetts:extent<length>parameterassociatedwithheight.Asspecifiedin[W3C‐TT]andincorporatedin[SMPTE‐TT],theheightofeachlineisafunctionofthesizeoflargestfontusedwithinthatlineandthetts:lineHeightsetting.GlyphspaintedintothePresentationBufferSHALLbelaidoutverticallywithinaregioninaccordancewiththefollowingparameters:
Atts:lineHeightof“100%”correspondswiththesizeofthelargestfontonaline.Forexample,alinewithcharactersof“10px”,“12px”and“14px”andatts:lineHeightof“100%”isequivalenttoatts:lineHeightof“14px”.
Inter‐baselineseparationisdefinedasfollows: Thevalueoftts:lineHeightiftts:lineHeightisspecified tts:lineHeight=”120%”iftts:lineHeight=”normal”(note:iftts:lineHeight
isnotspecified,“normal”isthedefaultvalueapplied). actuallineheightisroundeduptowholepixels.Forexample,alineheightof“12px”at
“120%”resultsin14.4pxandisroundedupto15px. Whitespaceinexcessoftts:fontHeightisallocatedevenly,withinapixel,topand
bottom(half‐leading).Notethatinter‐baselineseparationincludesanyleading.
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Notes: Toguaranteethatcontentflowedintoaregionrenderswithoutverticalclipping,itis
necessaryforthetts:extent<length>(height)parametertobeatleastthesumoftheactualheightofeachlineoftextintheregion.Forexample,threelinesof12pxcharacterswithatts:lineHeight=”normal”wouldrequirea<length>of(12px*120%*3)pixels.
Glyphsthatdonotextendbeyondthespecifictts:fontSizevaluewillnotcliptoporbottom.
6.6.5 Constraints
ThefollowingconstraintsapplytotheCFF‐TThypotheticalrendermodel.
Table6‐10–HypotheticalRenderModelConstraintsProperty ConstraintDocumentBufferSize 500x210bytesminimumforonedocument
DOMBufferSizes
Nospecificlimitations.TheDOMbuffersizesarelimitedbytheXMLdocumentsize,butthesizeoftheDOMbufferrelativetodocumentsizedependsonthespecificimplementation.Itisuptothedecoderimplementationtoensurethatsufficientmemoryisavailableforthe2DOMs.
6.7 DataStructureforCFF‐TTTrack
6.7.1 Introduction
Inthissection,theoperationalrulesforboxesandtheircontentsoftheCommonFileFormatforCFF‐TTsubtitletracksaredescribed.
6.7.2 Track Header Box (‘tkhd’)
TheTrackHeaderBox(‘tkhd’)SHALLconformtothedefinitioninSection2.3.5,withthefollowingadditionalormodifiedconstraints:
ThefollowingfieldsSHALLbesetasdefined: layer=‐1(infrontofvideoplane);and flags=thetrack_enabled,track_in_movie,andtrack_in_previewfields
SHALLeachbesetto1. ThewidthandheightfieldsSHALLbesetinaccordancewith[ISOTEXT]andwiththefollowing
additionalconstraints: Allsubtitletracks:ifthewidthandheightfieldsaresettoanon‐zerovalue,theaspect
ratiodefinedbythesefieldsSHALLmatchtheaspectratiooftheassociatedvideotrack;and Imagesubtitletracks:thewidthandheightSHALLbesettoanon‐zerovalueand
track_size_is_aspect_ratio_flagSHALLbesetto0;and
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TextsubtitletrackswhichusescalarlengthsinoneormoreCFF‐TTdocuments:thewidthandheightfieldsSHALLbesettoanon‐zerovalueandthetrack_size_is_aspect_ratio_flagfieldSHALLbesetto0;and
TextsubtitletrackswhichdonotusescalarlengthsinanyCFF‐TTdocuments: thewidthandheightfieldsSHOULDbesettovalueswhichpreciselydefinethe
aspectratiooftherootcontainerandthetrack_size_is_aspect_ratio_flagfieldSHOULDbesetto1.
thewidthandheightfieldsMAYbesetto0,andifoneissetto0theotherSHALLbesetto0.Inthiscase,thetrack_size_is_aspect_ratio_flagfieldSHALLbesetto0.
OthertemplatefieldsSHALLbesettotheirdefaultvalues.
6.7.3 Movie Fragment Box(‘moof’)
MovieFragmentsinsubtitletracksarerequiredtoconformtothefollowingconstrains: EverysubtitletrackMovieFragmentexceptthelastMovieFragmentofasubtitletrackSHALLhave
adurationofatleastonesecond. ThelastMovieFragmentofasubtitletrackMAYhaveadurationoflessthanonesecond.
6.7.4 Media Header Box (‘mdhd’)
TheMediaHeaderBox(‘mdhd’)SHALLconformtothedefinitioninSection2.3.6,withthefollowingadditionalconstraint:
ThetimescaleSHALLbesettothesamevalueasthetimescaleoftheassociatedvideotrack’sMediaHeaderBox(‘mdhd’).
6.7.5 Handler Reference Box (‘hdlr’)
ThesyntaxandvaluesfortheHandlerReferenceBox(‘hdlr’)forCFF‐TTsubtitletracksSHALLconformto[ISO]withthefollowingadditionalconstraints:
Thehandler_type fieldSHALLbesetto“subt”
ThenamefieldoftheHandlerReferenceBox(‘hdlr’)forCFF‐TTsubtitletracksSHOULDbesettothevalueofthe"MetatadataMovie/TrackMetadata/Track/Subtitle/Type" assignedtotheCFF‐TTsubtitletrackinMulti‐TrackRequiredMetadata(seeSection2.1.2.1)whenMulti‐TrackRequiredMetadataispresentintheDCC.WhenthereismorethanoneTypevaluedefinedforthesubtitletrack,thevaluesSHALLbeconcatenatedandcomma‐separatedinthename fieldoftheHandlerReferenceBox(‘hdlr’).
6.7.6 Subtitle Media Header Box (‘sthd’)
ThesyntaxandvaluesfortheSubtitleMediaHeaderBox(‘sthd’)SHALLconformto[ISO]Section8.4.5.
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6.7.7 Sample Description Box (‘stsd’)
ForCFF‐TTsubtitletracks,theSampleDescriptionBox(‘stsd’)SHALLcontainaXMLSubtitleSampleEntrythatcomplieswith[ISOTEXT]withthefollowingadditionalconstraints:
ThenamespacefieldofXMLSubtitleSampleEntrySHALLlistalloftheXMLnamespacesdeclaredinanyoftheCFF‐TTtrackdocumentsinthetrackwiththefollowingexceptions: thebuilt‐inXMLSchemanamespaces“http://www.w3.org/2001/XMLSchema”and
http://www.w3.org/2001/XMLSchema‐instanceSHALLNOTbelisted. anynamespacedeclarationwhichhasaprefixbeginningwiththethree‐lettersequence
"xml"SHALLNOTbelisted. ifaschemadefinesmultiplenamespaces,itSHOULDonlybelistedonce(forexample,only
...ns/ttmlisrecommendedtobeincluded,notboth...ns/ttmland...ns/ttml#style).ThenamespacefieldSHALLNOTlistanyothernamespaces.SeealsotherequirementsdefinedinSection6.8.
Theschema_locationfieldofXMLSubtitleSampleEntrySHALLincludetheXMLschemasforallofthenamespacessetinthenamespacefield.SeealsotherequirementsdefinedinSection6.8.
Theauxiliary_mime_typefieldofXMLSubtitleSampleEntrySHALLbesetto“image/png”ifimagesareusedintheCFF‐TTsubtitletrack.
6.7.8 Sub‐Sample Information Box (‘subs’)
ThesyntaxandvaluesfortheSub‐SampleInformationBox(‘subs’)SHALLconformto[ISOTEXT].
6.7.9 Track Fragment Run Box (‘trun’)
OneTrackFragmentRunBox(‘trun’)SHALLbepresentineachsubtitletrackfragment.
Thedata-offset-present,sample-size-presentandsample-duration-presentflagsSHALLbesetandcorrespondingvaluesprovided.OtherflagsSHALLNOTbeset.
6.7.10 Track Fragment Random Access Box (‘tfra’)
OneTrackFragmentRandomAccessBox(‘tfra’)SHALLbestoredintheMovieFragmentRandomAccessBox(‘mfra’)foreachsubtitletrackiftheMovieFragmentRandomAccessBox(‘mfra’)ispresent.
The‘tfra’forasubtitletrackSHALLlisteachofitssubtitletrackfragmentsasarandomlyaccessiblesample.
6.8 SignalingforCFF‐TTTracks
6.8.1 Text Subtitle Tracks
ACFF‐TTtextsubtitletrackhasthefollowingcharacteristics: EachCFF‐TTDocumentinthesubtitletrackcomplieswiththerestrictionsdefinedinSection6.2.2.4. Thesubtitletrackdoesnotcontainanyimagefiles.
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ACFF‐TTtextsubtitletrackSHALLbesignaledasfollows: ThenamepsacefieldofXMLSubtitleSampleEntryintheCFF‐TTsubtitletrackSampleDescription
Box(‘stsd’)SHALLinclude“http://www.w3.org/ns/ttml”.
Theschema_locationfieldofXMLSubtitleSampleEntryintheCFF‐TTsubtitletrackSampleDescriptionBox(‘stsd’)SHALLinclude“http://www.w3.org/ns/ttml cff-tt-text-ttaf1-dfxp-{DMEDIA_VERSION_POINTS}.xsd”.
The “MetadataMovie/TrackMetadata/Track/Subtitle/Format”assignedtotheCFF‐TTsubtitletrackinMulti‐TrackRequiredMetadata(seeSection2.1.2.1)SHALLbesetto“Text”ifMulti‐TrackRequiredMetadataispresentintheDCC.
Note:{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.
6.8.2 ImageSubtitle Tracks
ACFF‐TTimagesubtitletrackhasthefollowingcharacteristics: EachCFF‐TTDocumentinthesubtitletrackcomplieswiththerestrictionsdefinedinSection6.2.2.5.ACFF‐TTimagesubtitletrackSHALLbesignaledasfollows:
ThenamepsacefieldofXMLSubtitleSampleEntryintheCFF‐TTsubtitletrackSampleDescriptionBox(‘stsd’)SHALLinclude“http://www.w3.org/ns/ttml”.
Theschema_locationfieldofXMLSubtitleSampleEntryintheCFF‐TTsubtitletrackSampleDescriptionBox(‘stsd’)SHALLinclude“http://www.w3.org/ns/ttml cff-tt-image-ttaf1-dfxp-{DMEDIA_VERSION_POINTS}.xsd”.
The “MetadataMovie/TrackMetadata/Track/Subtitle/Format”assignedtotheCFF‐TTsubtitletrackinMulti‐TrackRequiredMetadata(seeSection2.1.2.1)SHALLbesetto“Image”ifMulti‐TrackRequiredMetadataispresentintheDCC.
Note:{DMEDIA_VERSION_POINTS}isaparameter,definedinAnnexE.
6.8.3 Combined Subtitle Tracks
The “MetadataMovie/TrackMetadata/Track/Subtitle/Format”assignedtotheCFF‐TTsubtitletrackinMulti‐TrackRequiredMetadata(seeSection2.1.2.1)SHALLNOTbesetto“combined”.Note:“combined”CFF‐TTsubtitletracksareprohibitedperSection6.2.2.
6.9 SubtitleLanguageConsiderations
6.9.1 Overview
CFF-TT subtitle tracks are associated with a “language”. This Section is intended to provide additional information regarding CFF-TT subtitle “languages”. In this section, unless explicitly specified otherwise, the term “Primary Language Subtag” is as defined in [RFC5646] and specified Language Subtags are per those defined in [IANA-LANG].
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6.9.2 Recommended Unicode Code Points perSubtitle Language
Table6‐11 defines the set of Unicode Code Points that SHOULD be used in text-based CFF-TT subtitle tracks that are associated with a “language” containing the specified “Primary Language Subtag”. Unicode Code Points are per those defined in [UNICODE].
Table6‐11–RecommendedUnicodeCodePointsperLanguageLanguage(Informative)
PrimaryLangSubtags(Normative)
UnicodeCodePoints(Normative)
All “x‐ALL”(forthepurposesofthisspecification,this[RFC5646]privateusesubtagsequenceisconsideredtorepresentallpossiblelanguagesasdefinedin[IANA‐LANG])
(BasicLatin)U+0020‐U+007E(Latin‐1Supplement)U+00A0‐U+00FF(LatinExtended‐A)U+0152:LATINCAPITALLIGATUREOEU+0153:LATINSMALLLIGATUREOEU+0160:LATINCAPITALLETTERSWITHCARONU+0161:LATINSMALLLETTERSWITHCARONU+0178:LATINCAPITALLETTERYWITHDIAERESISU+017D:LATINCAPITALLETTERZWITHCARONU+017E:LATINSMALLLETTERZWITHCARON(LatinExtended‐B)U+0192:LATINSMALLLETTERFWITHHOOK(SpacingModifierLetters)U+02DC:SMALLTILDE (CombiningDiacriticalMarks)U+0301:COMBININGACUTEACCENT(GeneralPunctuation)U+2010‐U+2015:DashesU+2016‐U+2027:GeneralpunctuationU+2030‐U+203A:Generalpunctuation(Currencysymbols)U+20AC:EUROSIGN(LetterlikeSymbols)U+2103:DEGREESCELSIUSU+2109:DEGREESFAHRENHEITU+2120:SERVICEMARKSIGNU+2122:TRADEMARKSIGN(NumberForms)U+2153–U+215F:Fractions(MathematicalOperators)U+2212:MINUSSIGNU+221E:INFINITY(BoxDrawing)U+2500:BOXDRAWINGSLIGHTHORIZONTALU+2502:BOXDRAWINGSLIGHTVERTICALU+250C:BOXDRAWINGSLIGHTDOWNANDRIGHTU+2510:BOXDRAWINGSLIGHTDOWNANDLEFTU+2514:BOXDRAWINGSLIGHTUPANDRIGHTU+2518:BOXDRAWINGSLIGHTUPANDLEFT(BlockElements)U+2588:FULLBLOCK(GeometricShapes)U+25A1:WHITESQUARE(MusicalSymbols)U+2669:QUARTERNOTEU+266A:EIGHTHNOTEU+266B:BEAMEDEIGHTHNOTES
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AlbanianLanguages(Informative)
PrimaryLangSubtags(Normative)
UnicodeCodePoints(Normative)
Albanian “sq” Sameasdefinedforthe“x‐ALL”subtagsequenceBalticLanguages(Informative)
PrimaryLangSubtags(Normative)
UnicodeCodePoints(Normative)
Latvian,Lithuanian “lv”,“lt” Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(LatinExtended‐A)”whichisre‐definedbelow(LatinExtended‐A)U+0100‐U+017F
FinnicLanguages(Informative)
PrimaryLangSubtags(Normative)
UnicodeCodePoints(Normative)
Finnish "fi" Sameasdefinedforthe“x‐ALL”subtagsequenceEstonian “et” Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(Latin
Extended‐A)”whichisre‐definedbelow(LatinExtended‐A)U+0100‐U+017F
GermanicLanguages(Informative)
PrimaryLangSubtags(Normative) UnicodeCodePoints(Normative)
Danish,Dutch/Flemish,English,German,Icelandic,Norwegian,Swedish
"da",“nl",“en”,"de","is","no","sv"
Sameasdefinedforthe“x‐ALL”subtagsequence
GreekLanguages(Informative)
PrimaryLangSubtags(Normative) UnicodeCodePoints(Normative)
Greek “el” Sameasdefinedforthe“x‐ALL”subtagsequence(CombiningDiacriticalMarks)U+0308:COMBININGDIAERESIS(GreekandCoptic)U+0386:GREEKCAPITALLETTERALPHAWITHTONOSU+0387:GREEKANOTELEIAU+0388–U+03CE:Letters
RomanicLanguages(Informative)
PrimaryLangSubtags(Normative) UnicodeCodePoints(Normative)
Catalan,French,Italian
“ca”,"fr","it" Sameasdefinedforthe“x‐ALL”subtagsequence
Portuguese,Spanish “pt”,“es” (Currencysymbols)U+20A1:COLONSIGNU+20A2:CRUZEIROSIGNU+20B3:AUSTRALSIGN
Romanian “ro” Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(LatinExtended‐A)”and“(LatinExtended‐B)”whichisre‐definedbelow(LatinExtended‐A)U+0100‐U+017F
(LatinExtended‐B)U+0192:LATINSMALLLETTERFWITHHOOKU+0218:LATINCAPITALLETTERSWITHCOMMABELOWU+0219:LATINSMALLLETTERSWITHCOMMABELOWU+021A:LATINCAPITALLETTERTWITHCOMMABELOWU+021B:LATINSMALLLETTERTWITHCOMMABELOW
SemiticLanguages(Informative)
PrimaryLangSubtags(Normative) UnicodeCodePoints(Normative)
Arabic “ar” Sameasdefinedforthe“x‐ALL”subtagsequence
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U+0609:ARABIC‐INDICPERMILLESIGNU+060C–U+060D:PunctuationU+061B:ARABICSEMICOLONU+061E:ARABICTRIPLEDOTPUNCTUATIONMARKU+061F:ARABICQUESTIONMARKU+0621–U+063A:BasedonISO8859‐6U+0640–U+064A:BasedonISO8859‐6U+064B–U+0652:PointsfromISO5559‐6U+0660–U+0669:Arabic‐IndicdigitsU+0670:ARABICLETTERSUPERSCRIPTALEFU+066A–U+066D:Punctuation
Hebrew “he” Sameasdefinedforthe“x‐ALL”subtagsequence(Hebrew)U+05B0–U+05C3:PointsandpunctuationU+05D0–U+05EA:BasedonISO8859‐8U+05F3–U+05F4:Additionalpunctuation
SlavicLanguages(Informative)
PrimaryLangSubtags(Normative) UnicodeCodePoints(Normative)
Croatian,Czech,Polish,Slovenian,Slovak
“hr”,“cs”,“pl”,“sl”,“sk” Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(LatinExtended‐A)”whichisre‐definedbelow(LatinExtended‐A)U+0100‐U+017F
Bosnian,Bulgarian,Macedonian,Russian,Serbian,Ukrainian
“bs”,“bg”,“mk”,“ru”,“sr”,“uk”
Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(LatinExtended‐A)”whichisre‐definedbelow(LatinExtended‐A)U+0100‐U+017F(SpacingModifierLetters)U+02BC:MODIFIERLETTERAPOSTROPHE(Cyrillic)U+0400–U+040F:CyrillicextensionsU+0410–U+044F:BasicRussianalphabetU+0450–U+045F:CyrillicextensionsU+048A–U+04F9:ExtendedCyrillic(LetterlikeSymbols)
6.9.2.1 U+2116:NUMEROSIGN
TurkicLanguages(Informative)
PrimaryLangSubtags(Normative)
UnicodeCodePoints(Normative)
Turkish “tr” Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(LatinExtended‐A)”whichisre‐defined
(LatinExtended‐A)U+0100‐U+017F
Kazakh “kk” Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(LatinExtended‐A)”whichisre‐defined
(LatinExtended‐A)U+0100‐U+017F
(Cyrillic)U+0400–U+040F:CyrillicextensionsU+0410–U+044F:BasicRussianalphabetU+0450–U+045F:CyrillicextensionsU+048A–U+04F9:ExtendedCyrillic
UgricLanguages(Informative)
PrimaryLangSubtags(Normative) UnicodeCodePoints(Normative)
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Hungarian “hu” Sameasdefinedforthe“x‐ALL”subtagsequence,exceptfor“(LatinExtended‐A)”whichisre‐definedbelow
(LatinExtended‐A)U+0100‐U+017F
(GeneralPunctuation)U+2052:COMMERCIALMINUSSIGN
(MiscellaneousMathematicalSymbols‐A)U+27E8:MATHEMATICALLEFTANGLEBRACKETU+27E9:MATHEMATICALRIGHTANGLEBRACKET
Note: it is expected that additional Language Subtags and associated Unicode Code Points will be added to a future release of this specification.
6.9.3 Reference Font Family per Subtitle Language
tts:fontFamily PrimaryLangSubtags ReferenceFontFamily
monospaceSerif AlllanguagesdefinedinD.2above. CourierNew:http://www.microsoft.com/typography/fonts/family.aspx?FID=10
proportionalSansSerif AlllanguagesdefinedinD.2abovewiththeexceptionofSemiticLanguages.
Arial:http://www.microsoft.com/typography/fonts/family.aspx?FID=8
Helvetica:http://www.linotype.com/en/526/Helvetica‐family.html
Notes: theReferenceFontFamilieswerechosenbecauseoftheircommonuse,generalavailabilityandthe
availabilityoflicense‐freemetricequivalentfontfamilies. PerSection6.6.4.2,fontsthatare‘metriccompatible’canbesubstitutedforReferenceFontFamily
(afontis‘metriccompatible’ifitdoesnotchangetextflow,althoughappearancemaybedifferent). It is expected that additional ReferenceFontFamilydefinitionsforotherLanguageswillbeaddedtoa
futurereleaseofthisspecification.
6.9.4 TypicalSubtitle Practice per Region (Informative)
Table6‐12 below provides an informative summary of subtitle languages commonly used in the listed regions. Primary language and Primary Language Subtag are indicated, with additional common region or script variant Language Subtags in brackets. Note that Table6‐11 provides Unicode Code Points associated with “Primary Language Subtag”.
Table6‐12–SubtitlesperRegion Region SubtitleLanguages(LangSubtags)
ALL(worldwide) English(“en”)
America(North)
ALL French(“fr”)[Québécois(“fr‐CA”)orParisian(“fr‐FR”)]
UnitedStates Spanish(“es”)[LatinAmerican(“es‐419”)]
America(CentralandSouth)
ALL Spanish(“es”)[LatinAmerican(“es‐419”)]
Brazil Portuguese(“pt”)[Brazilian(“pt‐BR”)]
Asia,MiddleEast,andAfrica
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Region SubtitleLanguages(LangSubtags)
China Chinese(“zh”)[SimplifiedMandarin(“zh‐cmn‐Hans”)]
Egypt Arabic(“ar”)
HongKong Chinese(“zh”)[Cantonese(“zh‐yue”)]
India Hindi(“hi”)
Tamil(“ta”)
Telugu(“te”)
Indonesia Indonesian(“id”)
Israel Hebrew(“he”)
Japan Japanese(“ja”)
Kazakhstan Kazakh(“kk”)
Malaysia StandardMalay(“zsm”)
SouthKorea Korean(“ko”)
Taiwan Chinese(“zh”)[TraditionalMandarin(“zh‐cmn‐Hant”)]
Thailand Thai(“th”)
Vietnam Vietnamese(“vi”)
Europe
Benelux(Belgium,Netherlands,andLuxembourg)
French(“fr”)[Parisian(“fr‐FR”)]
Dutch/Flemish(“nl”)
Denmark Danish(“da”)
Finland Finnish(“fi”)
France French(“fr”)[Parisian(“fr‐FR”)]
Arabic(“ar”)
Germany German(“de”)
Turkish(“tr”)
Italy Italian(“it”)
Norway Norwegian(“no”)
Spain Spanish(“sp”)[Castilian(“sp‐ES”)]
Catalan(“ca”)
Sweden Swedish(“sv”)
Switzerland French(“fr”)[“fr‐CH”or“fr‐FR”]
German(“de”)[“de‐CH”]
Italian(“it”)[“it‐CH”]
Albania Albanian(“sq”)
Bulgaria Bulgarian(“bg”)
Croatia Croatian(“hr”)
CzechRepublic Czech(“cs”)
Estonia Estonian(“et”)
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Region SubtitleLanguages(LangSubtags)
Greece Greek(“el”)
Hungary Hungarian(“hu”)
Iceland Icelandic(“is”)
Latvia Latvian(“lv”)
Lithuania Lithuanian(“lt”)
Macedonia Macedonian(“mk”)
Poland Polish(“pl”)
Portugal Portuguese(“pt”)[Iberian(“pt‐PT”)]
Romania Romanian(“ro”)
Russia Russian(“ru”)
Serbia Serbian(“sr”)
Slovakia Slovak(“sk”)
Slovenia Slovenian(“sl”)
Turkey Turkish(“tr”)
Ukraine Ukrainian(“uk”)
Note: it is expected that additional Language Subtags will be added to future releases of this specification.
6.10 ClosedCaptionSubtitlesTranscodedfromCEA608orCEA708
Subtitletracksauthoredforthedeafandhardofhearing(closedcaptioning)aresignaledintherequiredmetadatawiththetype"SDH".AllsubtitletracksarerequiredtoconformtoaCFF‐TTProfilewhich,asnotedinSection6.2.2,arederivedfromtheSMPTETTProfiledefinedin[SMPTE‐TT].WhenSDHtracksaretranscodedfromCEA608[CEA608]bitstreamsthetracksSHALLconformwiththemetadataprovisionsdefinedinSMPTERP2052‐10[SMPTE‐608],Section5.3,specificallythatm608:channelSHALLbepresentandallothermetadatapresentintheoriginalCEA608bitstreamSHOULDbeincluded.TracksSHOULDcomplywiththeentiretyof[SMPTE‐608].WhenSDHtracksaretranscodedfromCEA708[CEA708]bitstreamsthetracksSHALLconformwiththemetadataprovisionsdefinedinSMPTERP2052‐11[SMPTE‐708],Section5.4.TracksSHOULDcomplywiththeentiretyof[SMPTE‐708].Whentunneldataisprovided,itSHALLcomplywiththetunnelencodingprovisionsof[SMPTE‐TT],[SMPTE‐608]and[SMPTE‐708]asappropriate.
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AnnexA.CFFParameters
TableA‐1–CurrentVersionParameter Value DescriptionDMEDIA_VERSION_NOPOINTS 210 ThisversionoftheDMediaspecification,withoutpoint
notation.DMEDIA_VERSION_POINTS 2.1.0 ThisversionoftheDMediaspecification,withpoint
notation.
TableA‐2–CompatibleVersionDMediaCompatibleVersion Description2.1.0 CommonFileFormat&MediaFormatsSpecificationV2.12.0.0 CommonFileFormat&MediaFormatsSpecificationV2.0
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AnnexB.MediaProfiles
B.1. PDMediaProfile
B.1.1. Overview
ThePDMediaProfiledefinesanaudio‐visualcontentinteroperabilitypointforportabledevices.ThePDMediaProfileisidentifiedbythe‘cfpd’fourcharactercoderegisteredwith[MP4RA].
B.1.2. Constraints on Encryption
ContentconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection3,EncryptionofTrackLevelData,withtheadditionalconstraintsdefinedhere.
EncryptedtracksSHALLrestrictthevalueofdefault_IV_sizein‘tenc’to0x08,andthevalueofIV_sizein‘seig’(whensamplegroupsarepresent)to0x00or0x08;and
EachencryptedaudiotrackSHALLbeencryptedusingasinglekey;and EachencryptedvideotrackSHALLbeencryptedusingasinglekey;and SubtitletracksSHALLNOTbeencrypted.
Note:Encryptionisnotmandatory.
B.1.3. Constraints on Video
B.1.3.1. Overview
VideotracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection4,VideoElementaryStreams,withtheadditionalconstraintsdefinedhere.
ThevideotrackSHALLbeanAVCVideotrackasdefinedinSection4.3.
B.1.3.2. Constraintson[H264]ElementaryStreams
B.1.3.2.1. ProfileandLevel[H264]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H264]ProfileandLevelconstraints:
ConstrainedBaselineProfileasdefinedin[H264]. UptoLevel1.3asdefinedin[H264].
B.1.3.2.2. MaximumBitrate[H264]elementarystreamsconformingtothisMediaProfileSHALLNOTexceedthemaximumbitratedefinedby[H264]forthechosen[H264]ProfileandLevel(note:ConstrainedBaselineProfileatLevel1.3istheworsecasewitha768x103bits/secmaximumbitrate).SeeSection4.3.2.4formoreinformationonthecalculationof[H264]elementarystreammaximumbitrate.
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B.1.3.3. ConstraintsonMastering
NALStructuredVideostreamsconformingtothisMediaProfileSHALLbeencodedusingthecolorparametersdefinedby[R709].Presentationofcontentisassumedtooccuronadisplaywhichusestheelectro‐optictransferfunctionspecifiedin[R1886]withapeakluminanceof100cd/m2.Itisrecommendedthatcontentbegradedwithareferenceviewingenvironmentthatcomplieswith[R2035].
B.1.3.4. ConstraintsonEncoding
NALStructuredVideostreamsconformingtothisMediaProfile: SHALLhavethefollowingpre‐determinedvalues:
video_full_range_flag,ifpresent,SHALLbesetto0.
B.1.3.5. ConstraintsonPictureFormats
NALStructuredVideostreamsconformingtothisMediaProfileSHALLNOTexceedthefollowingcodedpictureformatconstraints:
Maximumencodedhorizontalsamplecountof416samples;and Maximumencodedverticalsamplecountof240samples;and Maximumframerateof30000÷1000(framerateiscalculatedasperSection4.3.2.5andSection
4.4.2.7).
B.1.4. Constraints on Audio
AudiotracksconformingtothisMediaProfileSHALLcomplywith: alloftherequirementsandconstraintsdefinedinSection5,AudioElementaryStreams,. oneoftheallowedcombinationsofaudioformat,maximumnumberofchannels,maximum
elementarystreambitrate,andsampleratedefinedbelow.TableB‐1–AllowedAudioFormatsinPDMediaProfile
AudioFormat Max.No.Channels SampleRate Max.Bitrate BitrateCalculationMPEG‐4AAC[2‐Channel] 2 48kHz 192Kbps Section5.3.2.2.2.4MPEG‐4HEAACv2 2 48kHz 192Kbps Section5.3.4.2.2.3MPEG‐4HEAACv2withMPEGSurround
5.1 48kHz 192Kbps Section5.3.5.2.2.3
B.1.5. Constraints on Subtitles
SubtitletracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection6,SubtitleElementaryStreams,withthefollowingadditionalconstraints:
ACFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)widthfieldvalueSHALLNOTexceedthemaximumhorizontalsamplecountdefinedinB.1.3.5,andtheCFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)heightfieldvalueSHALLNOTexceedthemaximumverticalsamplecountdefinedinB.1.3.5; and
ACFF‐TTsubtitletrackSHALLNOTexceedtheconstraintsdefinedinTableB‐2below;and
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TableB‐2–HypotheticalRenderModelConstraints(General)Property ConstraintSubtitlefragment/samplesize Totalsamplesize<=500x210bytesNormalizedbackgrounddrawingperformancefactor(BDraw)
12(PerformanceFactor(1/s)
ACFF‐TTtextsubtitletrackSHALLNOTexceedtheconstraintsdefinedinTableB‐3below;andTableB‐3–HypotheticalRenderModelConstraints(Textsubtitle)
Property ConstraintMaximumNormalizedGlyphBufferSize 1(BufferSize)Normalizedglyphcopyperformancefactor(GCpy) 12(PerformanceFactor(1/s)Non‐CJKtextrenderingperformancefactor(Ren) 1.2(PerformanceFactor(1/s)CJKtextrenderingperformancefactor(Ren) 0.6(PerformanceFactor(1/s)
Note: “CJK”inTableB‐3represents“Chinese,Japanese,Korean”Glyphs. TableB‐3definedperformanceappliestoallsupportedfontstyles(includingoutline
border). CFF‐TTimagesubtitletracksSHALLNOTbeused.
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B.2. SDMediaProfile
B.2.1. Overview
TheSDMediaProfiledefinesanaudio‐visualcontentinteroperabilitypointforstandarddefinitiondevices.TheSDMediaProfileisidentifiedbythe‘cfsd’fourcharactercoderegisteredwith[MP4RA].
B.2.2. Constraints on Encryption
ContentconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection3,EncryptionofTrackLevelData,withtheadditionalconstraintsdefinedhere.
EncryptedtracksSHALLcomplywiththeconstraintsdefinedinAnnexB.1.2.Note:Encryptionisnotmandatory.
B.2.3. Constraints on Video
B.2.3.1. Overview
VideotracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection4,VideoElementaryStreams,withtheadditionalconstraintsdefinedhere.
B.2.3.2. Constraintson[H264]ElementaryStreams
B.2.3.2.1. ProfileandLevel[H264]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H264]ProfileandLevelconstraints:
ConstrainedBaselineProfileasdefinedin[H264]. UptoLevel3asdefinedin[H264].
B.2.3.2.2. MaximumBitrateH264]elementarystreamsconformingtothisMediaProfileSHALLNOTexceedthemaximumbitratedefinedby[H264]forthechosen[H264]ProfileandLevel(note:ConstrainedBaselineProfileatLevel3istheworsecasewithabe10x106bits/secmaximumbitrate).SeeSection4.3.2.4formoreinformationonthecalculationof[H264]elementarystreammaximumbitrate.
B.2.3.3. Constraintson[H265]ElementaryStreams
B.2.3.3.1. Profile,TierandLevel[H265]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H265]Profile,TierandLevelconstraints:
MainProfileasdefinedin[H265]. MainTierasdefinedin[H265]. UptoLevel3.1asdefinedin[H265].
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B.2.3.3.2. MaximumBitrate[H265]elementarystreamsconformingtothisMediaProfileSHALLNOTexceedthemaximumbitratedefinedby[H265[forthechosen[H265]Profile,TierandLevel(note:MainProfile,MainTierandLevel3.1istheworsecasewitha10x106bits/secmaximumbitrate).SeeSection4.4.2.6formoreinformationonthecalculationof[H265]elementarystreammaximumbitrate.
B.2.3.4. ConstraintsonMastering
NALStructuredVideostreamsconformingtothisMediaProfile: SHOULDbeencodedusingthecolorparametersdefinedby[R709];and SHALLbeencodedwiththefollowingcolorparameters:
for24Hz,30Hz&60Hzcontent:thecolorparametersdefinedby[R709],orthecolorparametersdefinedfor525‐linevideosystemsasper[R601];or
for25Hz&50Hzcontent:thecolorparametersdefinedby[R709],orthecolorparametersdefinedfor625‐PALvideosystemsasper[R1700].
Presentationofcontentisassumedtooccuronadisplaywhichusestheelectro‐optictransferfunctionspecifiedin[R1886]withapeakluminanceof100cd/m2.Itisrecommendedthatcontentbegradedwithareferenceviewingenvironmentthatcomplieswith[R2035].
B.2.3.5. ConstraintsonEncoding
NALStructuredVideostreamsconformingtothisMediaProfile: SHALLhavethefollowingpre‐determinedvalues:
video_full_range_flag,ifpresent,SHALLbesetto0. colour_description_present_flagSHALLbesetto1ifthecolorparametersfrom
[R709]arenotused.
B.2.3.6. ConstraintsonPictureFormats
NALStructuredVideostreamsconformingtothisMediaProfileSHALLNOTexceedthefollowingcodedpictureformatconstraints:
Maximumencodedhorizontalsamplecountof854samples;and Maximumencodedverticalsamplecountof480samples;and Maximumframerateof60000÷1000(framerateiscalculatedasperSection4.3.2.5andSection
4.4.2.7).
B.2.4. Constraints on Audio
AudiotracksconformingtothisMediaProfileSHALLcomplywith: alloftherequirementsandconstraintsdefinedinSection5,AudioElementaryStreams,. oneoftheallowedcombinationsofaudioformat,maximumnumberofchannels,maximum
elementarystreambitrate,andsampleratedefinedineitherofthetablesbelow.
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TableB‐4–AllowedAudioFormatsinSDMediaProfileAudioFormat Max.No.
ChannelsSampleRate Max.Bitrate BitrateCalculation
MPEG‐4AAC[2‐Channel] 2 48kHz 192Kbps Section5.3.2.2.2.4MPEG‐4HEAACV2level4[5.1‐channel]
5.1 48kHz 1440Kbps Section5.3.3.2.2.5
MPEG‐H3DAudio 5.1 48kHz 2016Kbps Section5.4.2.2AC‐3(DolbyDigital) 5.1 48kHz 640Kbps Section5.5.1.2.3EnhancedAC‐3(DolbyDigitalPlus)
5.1 48kHz 3024Kbps Section5.5.2.2.5
AC‐4 5.1 48KHz 1512Kbps Section5.6.4.2.3DTS 5.1 48kHz 1536Kbps Section5.6.2.2DTS‐HD 5.1 48kHz 3018Kbps Section5.6.2.2
TableB‐5–AllowedEnhancedAudioFormatsinSDMediaProfileAudioFormat Max.No.
ChannelsSampleRate Max.Bitrate BitrateCalculation
MPEG‐4HEAACV2level6[5.1,7.1‐Channel]
7.1 48kHz 2016Kbps Section5.3.3.2.2.5
MPEG‐H3DAudio 7.1 48kHz 2592Kbps Section5.4.2.2EnhancedAC‐3(DolbyDigitalPlus)
7.1 48kHz 3024Kbps Section5.5.2.2.5
AC‐4 7.1 48kHz,96kHz,192kHz
6048Kbps Section5.6.4.2.3
DTS 6.1 48kHz 1536Kbps Section5.6.2.2 5.1 48kHz,96kHz 1536Kbps Section5.6.2.2DTS‐HD 7.1 48kHz,96kHz 6123Kbps Section5.6.2.2DTS‐HDMasterAudio 8 48kHz,96kHz,
192kHz24.5Mbps Section5.6.2.2
MLP(DolbyTrueHD) 8 48kHz,96kHz,192kHz
18Mbps Section5.5.3.2.4
B.2.5. Constraints on Subtitles
SubtitletracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection6,SubtitleElementaryStreams,withthefollowingadditionalconstraints:
ACFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)widthfieldvalueSHALLNOTexceedthemaximumhorizontalsamplecountdefinedinB.2.3.6,andtheCFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)heightfieldvalueSHALLNOTexceedthemaximumverticalsamplecountdefinedinB.2.3.6; and
ACFF‐TTsubtitletrackSHALLNOTexceedtheconstraintsdefinedinTableB‐2;and ACFF‐TTtextsubtitletrackSHALLNOTexceedtheconstraintsdefinedinTableB‐3;and ACFF‐TTimagesubtitletrackSHALLNOTexceedtheconstraintsdefinedinTableB‐6.
TableB‐6–HypotheticalRenderModelConstraints(Imagesubtitle)Property ConstraintReferenceimagesize Singleimagesize<=100x210bytes
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EncodedImageBufferSize
500x210bytes.Note:Samplesizeislimitedto500x210bytes,butaCFF‐TTdocumentcanbearbitrarilysmall,sonearlytheentiresubtitlesamplecouldbefilledwithimagedata.
DecodedImageBuffersize2x220pixelsforeachofthetwoDecodedImageBuffers.ADecodedImageBuffercanbufferallde‐compressedimagesfromasubtitlesample.
ImageDecodingrate 1x220pixelspersecondNormalizedimagecopyperformancefactor(ICpy)
6(PerformanceFactor(1/s)
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B.3. HDMediaProfile
B.3.1. Overview
TheHDMediaProfiledefinesanaudio‐visualcontentinteroperabilitypointforhighdefinitiondevices.TheHDMediaProfileisidentifiedbythe‘cfhd’fourcharactercoderegisteredwith[MP4RA].
B.3.2. Constraints on Encryption
ContentconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection3,EncryptionofTrackLevelData,withtheadditionalconstraintsdefinedhere.
EncryptedtracksSHALLcomplywiththeconstraintsdefinedinAnnexB.1.2.Note:Encryptionisnotmandatory.
Note:Encryptionisnotmandatory.
B.3.3. Constraints on Video
VideotracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection4,VideoElementaryStreams,withtheadditionalconstraintsdefinedhere.
B.3.3.1. Constraintson[H264]ElementaryStreams
B.3.3.1.1. ProfileandLevel[H264]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H264]ProfileandLevelconstraints:
ConstrainedBaselineProfile,MainProfileorHighProfileasdefinedin[H264]. UptoLevel4asdefinedin[H264].
B.3.3.1.2. MaximumBitrate[H264]elementarystreamsconformingtothisMediaProfileSHALLNOTexceedthemaximumdefinedby[H264]forthechosen[H264]ProfileandLevel(note:HighProfileatLevel4istheworsecasewitha25.0x106bits/secmaximumbitrate).SeeSection4.3.2.4formoreinformationonthecalculationof[H264]elementarystreammaximumbitrate.
B.3.3.2. Constraintson[H265]ElementaryStreams
B.3.3.2.1. Profile,TierandLevel[H265]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H265]Profile,TierandLevelconstraints:
MainProfileorMain10Profileasdefinedin[H265]. MainTierasdefinedin[H265]. UptoLevel4.1asdefinedin[H265].
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B.3.3.2.2. MaximumBitrate[H265]elementarystreamsconformingtothisProfileSHALLNOTexceedthemaximumdefinedby[H265]forthechosen[H265]Profile,TierandLevel(note:Main10Profile,MainTierandLevel4.1istheworsecasewitha20.0x106bits/secmaximumbitrate).SeeSection4.4.2.6formoreinformationonthecalculationof[H265]elementarystreammaximumbitrate.
B.3.3.3. ConstraintsonMastering
NALStructuredVideostreamsconformingtothisMediaProfileSHALLbeencodedusingthecolorparametersdefinedby[R709].Presentationofcontentisassumedtooccuronadisplaywhichusestheelectro‐optictransferfunctionspecifiedin[R1886]withapeakluminanceof100cd/m2.Itisrecommendedthatcontentbegradedwithareferenceviewingenvironmentthatcomplieswith[R2035].
B.3.3.4. ConstraintsonEncoding
NALStructuredVideostreamsconformingtothisMediaProfile: SHALLhavethefollowingpre‐determinedvalues:
video_full_range_flag,ifpresent,SHALLbesetto0.
B.3.3.5. ConstraintsonPictureFormats
NALStructuredVideostreamsconformingtothisMediaProfileSHALLNOTexceedthefollowingcodedpictureformatconstraints:
Maximumencodedhorizontalsamplecountof1920samples;and Maximumencodedverticalsamplecountof1080samples;and Maximumframerateof60000÷1000(framerateiscalculatedasperSection4.3.2.5andSection
4.4.2.7).
B.3.4. Constraints on Audio
AudiotracksconformingtothisMediaProfileSHALLcomplywith: alloftherequirementsandconstraintsdefinedinSection5,AudioElementaryStreams,. oneoftheallowedcombinationsofaudioformat,maximumnumberofchannels,maximum
elementarystreambitrate,andsampleratedefinedinAnnexB.2.4.
B.3.5. Constraints on Subtitles
SubtitletracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.2.5exceptasfollows:
ACFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)widthfieldvalueSHALLNOTexceedthemaximumhorizontalsamplecountdefinedinB.3.3.5,andtheCFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)heightfieldvalueSHALLNOTexceedthemaximumverticalsamplecountdefinedinB.3.3.5.
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B.4. xHDMediaProfile
B.4.1. Overview
ThexHDMediaProfiledefinesanaudio‐visualcontentinteroperabilitypointforhighdefinitiondevicessupportinghighbitrate.ThexHDMediaProfileisidentifiedbythe‘cfxd’coderegisteredwith[MP4RA].
B.4.2. Constraints on Encryption
ContentconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection3,EncryptionofTrackLevelData,withtheadditionalconstraintsdefinedhere.
EachencryptedaudiotrackSHALLbeencryptedusingasinglekey;and EachencryptedvideotrackMAYbeencryptedusingmorethanonekey;and SubtitletracksSHALLNOTbeencrypted;and ForagivenKID,InitializationVectorsSHALLNOTbere‐usedandSHALLfollowtheguidelines
outlinedin[CENC]Section9.2and9.3.ThisuniquenessconstraintappliestoallInitializationVectorsthatareexplicitlysetinthefileandthosethatareimplicitlygeneratedbyAES‐CTR.
Note:Encryptionisnotmandatory.
B.4.3. Constraints on Video
B.4.3.1. Overview
VideotracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection4,VideoElementaryStreams,withtheadditionalconstraintsdefinedhere.
B.4.3.2. Constraintson[H264]ElementaryStreams
B.4.3.2.1. ProfileandLevel[H264]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H264]ProfileandLevelconstraints:
ConstrainedBaselineProfile,MainProfileorHighProfileasdefinedin[H264]. UptoLevel4.1asdefinedin[H264].
B.4.3.2.2. MaximumBitrate[H264]elementarystreamsconformingtothisMediaProfileSHALLNOTexceedamaximuminputbitrateof40.0x106bits/sec.SeeSection4.3.2.4formoreinformationonthecalculationof[H264]elementarystreammaximumbitrate.
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B.4.3.3. Constraintson[H265]ElementaryStreams
B.4.3.3.1. Profile,TierandLevel[H265]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H265]Profile,TierandLevelconstraints:
MainProfileorMain10Profileasdefinedin[H265]. MainTierorHighTierasdefinedin[H265]. UptoLevel4.1asdefinedin[H265].
B.4.3.3.2. MaximumBitrate[H265]elementarystreamsconformingtothisProfileSHALLNOTexceedamaximuminputbitrateof40.0x106bits/secmaximumbitrate).SeeSection4.4.2.6formoreinformationonthecalculationof[H265]elementarystreammaximumbitrate.
B.4.3.4. ConstraintsonMastering
NALStructuredVideostreamsconformingtothisMediaProfileSHALLbeencodedusingthecolorparametersdefinedby[R709].Presentationofcontentisassumedtooccuronadisplaywhichusestheelectro‐optictransferfunctionspecifiedin[R1886]withapeakluminanceof100cd/m2.Itisrecommendedthatcontentbegradedwithareferenceviewingenvironmentthatcomplieswith[R2035].
B.4.3.5. ConstraintsonEncoding
NALStructuredVideostreamsconformingtothisMediaProfile: SHALLhavethefollowingpre‐determinedvalues:
video_full_range_flag,ifpresent,SHALLbesetto0.
B.4.3.6. ConstraintsonPictureFormats
NALStructuredVideostreamsconformingtothisMediaProfileSHALLNOTexceedthefollowingcodedpictureformatconstraints:
Maximumencodedverticalsamplecountof1080samples. Maximumframerateof60000÷1000(framerateiscalculatedasperSection4.3.2.5andSection
4.4.2.7).
B.4.4. Constraints on Audio
AudiotracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.3.4.
B.4.5. Constraints on Subtitles
SubtitletracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.3.5.
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B.5. UHDMediaProfile
B.5.1. Overview
TheUHDMediaProfiledefinesanaudio‐visualcontentinteroperabilitypointforUltra‐HDdefinitiondevices.TheUHDMediaProfileisidentifiedbythe‘cfud’fourcharactercoderegisteredwith[MP4RA].
B.5.2. Constraints on Encryption
ContentconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection3,EncryptionofTrackLevelData,withtheadditionalconstraintsdefinedhere.
EachencryptedaudiotrackSHALLbeencryptedusingasinglekey;and EachencryptedvideotrackMAYbeencryptedusingmorethanonekey;and SubtitletracksSHALLNOTbeencrypted;and ForagivenKID,InitializationVectorsSHALLNOTbere‐usedandSHALLfollowtheguidelines
outlinedin[CENC]Section9.2and9.3.ThisuniquenessconstraintappliestoallInitializationVectorsthatareexplicitlysetinthefileandthosethatareimplicitlygeneratedbyAES‐CTR.
Note:Encryptionisnotmandatory.
B.5.3. Constraints on Video
VideotracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection4,VideoElementaryStreams,withtheadditionalconstraintsdefinedhere.
ThevideotrackSHALLbeanHEVCVideotrackasdefinedinSection4.4.
B.5.3.1. Constraintson[H265]ElementaryStreams
B.5.3.1.1. Profile,TierandLevel[H265]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowing[H265]Profile,TierandLevelconstraints:
MainProfileorMain10Profileasdefinedin[H265]. MainTierorHighTierasdefinedin[H265]. UptoLevel5.1asdefinedin[H265].
B.5.3.1.2. MaximumBitrate[H265]elementarystreamsconformingtothisProfileSHALLNOTexceedamaximuminputbitrateof100.0x106bits/sec;seeSection4.4.2.5formoreinformationonthecalculationof[H265]elementarystreammaximumbitrate.
B.5.3.2. ConstraintsonMastering
NALStructuredVideostreamsconformingtothisMediaProfileSHALLbeencodedusingthecolorparametersdefinedby[R709]orthecolorparametersdefinedby[R2020].
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Presentationofcontentisassumedtooccuronadisplaywhichusestheelectro‐optictransferfunctionspecifiedin[R1886]withapeakluminanceof100cd/m2.Itisrecommendedthatcontentbegradedwithareferenceviewingenvironmentthatcomplieswith[R2035].
B.5.3.3. ConstraintsonEncoding
NALStructuredVideostreamsconformingtothisMediaProfile: SHALLhavethefollowingpre‐determinedvalues:
colour_description_present_flagSHALLbesetto1ifthecolorparametersfrom[R709]arenotused.
colour_primariesSHALLbepresentandsetto9ifthecolorparametersfrom[R2020]areused.
chroma_sample_loc_type_top_fieldandchroma_sample_loc_type_bottom_fieldSHALLbepresentandsetto2,whencolorparametersfrom[R2020]areused.
transfer_chracteristicsSHALLbepresentandbesetto14ifthecolorparametersfrom[R2020]areused.
matrix_coefficientsSHALLbepresentandbesetto9ifthecolorparametersfrom[R2020]areused.
B.5.3.4. ConstraintsonPictureFormats
NALStructuredVideostreamsconformingtothisMediaProfileSHALLNOTexceedthefollowingcodedpictureformatconstraints:
Maximumencodedhorizontalsamplecountof3840samples;and Maximumencodedverticalsamplecountof2160samples. Maximumframerateof60000÷1000(framerateiscalculatedasperSection4.4.2.7).
B.5.4. Constraints on Audio
AudiotracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.3.4.
B.5.5. Constraints on Subtitles
SubtitletracksconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.3.5exceptasfollows:
ACFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)widthfieldvalueSHALLNOTexceedthemaximumhorizontalsamplecountdefinedinB.5.3.4,andtheCFF‐TTsubtitletrack’sTrackHeaderBox(‘tkhd’)heightfieldvalueSHALLNOTexceedthemaximumverticalsamplecountdefinedinB.5.3.4;and
ACFF‐TTimagesubtitletrackSHALLbeauthoredtonotexceedtheimagedecodingrateinTableB‐7.
TableB‐7–HypotheticalRenderModelConstraints(Imagesubtitle)
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Property ConstraintImageDecodingrate 4x220pixelspersecond
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B.6. HDR10MediaProfileDefinition
B.6.1. Overview
TheHDR10MediaProfiledefinesanaudio‐visualcontentinteroperabilitypointforHighDynamicRangedevices.TheHDR10MediaProfileisidentifiedbythe‘cfh1’fourcharactercoderegisteredwithMP4RegistrationAuthority(http://mp4ra.org).
B.6.2. Constraints on Encryption
ContentconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.5.2.
B.6.3. Constraints on Video
VideotracksconformingtothisMediaProfileshallcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.5.3,withtheadditionalconstraintsdefinedhere.
B.6.3.1. Constraintson[H265]ElementaryStreams
B.6.3.1.1. 4 5 BProfile,TierandLevel[H265]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowingHEVCProfile,TierandHEVCLevelconstraints: Main10Profileasdefinedin[H265].
B.6.3.2. ConstraintsonMastering
NALStructuredVideostreamsconformingtothisMediaProfileSHALLbeencodedusingthecolorparametersdefinedby[R2020].NALStructuredVideostreamsconformingtothisMediaProfileSHALLbegradedusingthereferenceelectro‐optictransferfunctionspecifiedin[SMPTE‐2084].
B.6.3.3. ConstraintsonEncoding
NALStructuredVideostreamsconformingtothisMediaProfile: SHALLhavethefollowingpre‐determinedvalues:
transfer_characteristicsSHALLbesetto16forthereferenceelectro‐optictransferfunctionspecifiedin[SMPTE‐2084].
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B.7. DolbyVision(“DV”)ProfileDefinition
B.7.1. Overview
TheDVMediaProfiledefinesaudio‐visualcontentinteroperabilitypointsforHighDynamicRangedevicesutilizingDolbyVisiontechnology.TheconfigurationofDolbyVisioninthisProfileiscomprisedofaBaseLayervideotrack(“BL”)withtheadditionofanEnhancementLayervideotrack(“DV‐EL”).TheBLisconformantwithanotherMediaProfiledefinedinthisspecificationandcanbedecodedbydevicessupportingthatMediaProfile.TheELconsistsofadditional[H264]or[H265]conformantvideoand/orDolbyVisionHDRmetadata.Forexample,whenanELisdecodedandcombinedwithadecodedBL,thisresultsinanenhancedHDRvideooutput(i.e.conformingtoRec2020&SMPTE2084).Note:TheDVELdoesnotnecessarilyconformtoallthe“videotrack”provisionsthroughoutthisspecification.See[DV]fordetails.Forexample,itmightnotusethe‘avc3’sampletype.TheDVMediaProfileisidentifiedbythe‘cfdv’fourcharactercodesregisteredwiththeMP4RegistrationAuthority(http://mp4ra.org).
B.7.2. Constraints on Encryption
TheDV‐ELvideotrackSHALLconformtotheencryptionconstraintsfortheBLvideotrack.
B.7.3. Constraints on Video
B.7.3.1. BaseLayer(“BL”)
TheBLvideotrackSHALLconformtooneoftheHD,xHD,UHDorHDR10MediaProfiles.
B.7.3.2. DVEnhancementLayer(“DV‐EL”)
TheDV‐ELbitstreamandtrackSHALLbeasdefinedin[DV].InadditiontoaBLvideotrack,thereSHALLalsobeaDV‐ELtrack.Note:From[DV],DV‐ELhasthefollowingproperties: canbeencodedin,andcomplieswith,either[H264]or[H265].AlthoughdecodingDV‐ELdoesnot
resultinviewablepictures,itdoesconformtothesyntaxof[H264]or[H265]asappropriate;and thesyntaxandvaluesforvisualsampleentryareeitherDolbyVisionAVCSampleEntry(‘dvav’)
orDolbyVisionHEVCSampleEntry(‘dvhe’);and theframerateandDPBsize(innumberofframes)areidenticaltotheBLvideotrack;and iftheBLsamplecontainsanIDRframe,theELsamplemusthaveanIDRframeatthesame
presentationtime;and fragmentdurationsandpresentationtimesareidenticaltotheBLvideotrack;and eachELhasoneandonlyoneassociatedBLandviceversa(i.e.tracksarepaired1:1.Note:TheDVELdoesnotnecessarilyconformtoallthe“videotrack”provisionsthroughoutthisspecification.See[DV]fordetails.Forexample,itmightnotusethe‘avc1’sampletype.
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B.7.3.3. MaximumBitrate
ThemaximumbitrateofDV‐ELSHALLbecalculatedbyimplementationofthebufferandtimingmodeldefinedineither[H264]or[H265]AnnexCasappropriateforthetypeofvideocoding.WhenDolbyVisionEnhancementLayertrackispresentthemaximumbitrateisfurtherconstrainedasfollows:thesumofthebitratesfortheBaseLayervideoandtheDV‐ELSHALLnotexceedthemaximumbitratethatappliestojusttheBaseLayervideointhatprofile.
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B.8. HDR12MediaProfileDefinition
B.8.1. Overview
Thesinglestream12‐bitHDRMediaProfiledefinesanaudio‐visualcontentinteroperabilitypointforHighDynamicRangedevicessupportingcontentencodedin12‐bitcolor.TheHDRMediaProfileisidentifiedbythe‘cfh2’fourcharactercoderegisteredwithMP4RegistrationAuthority(http://mp4ra.org).
B.8.2. Constraints on Encryption
ContentconformingtothisMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.5.2.
B.8.3. Constraints on Video
VideotracksconformingtothisMediaProfileshallcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.5.3,withtheadditionalconstraintsdefinedhere.
B.8.3.1. Constraintson[H265]ElementaryStreams
B.8.3.1.1. Profile,TierandLevel[H265]elementarystreamsconformingtothisMediaProfileSHALLcomplywiththefollowingHEVCProfile,Tier,Level,andMaximumBitrateconstraints:
Main12Profileasdefinedin[H265]
B.8.3.1.2. MaximumBitrate[H265]elementarystreamsconformingtothisProfileshallNOTexceedamaximuminputbitrateof150.0x106bits/sec;seeSection4.4.2.5formoreinformationonthecalculationof[H265]elementarystreammaximumbitrate.
B.8.3.2. ConstraintsonMastering
NALStructuredVideostreamsconformingtothisMediaProfileSHALLbeencodedusingthecolorparametersdefinedby[R2020].NALStructuredVideostreamsconformingtothisMediaProfileSHALLbegradedusingthereferenceelectro‐optictransferfunctionspecifiedin[SMPTE‐2084].
B.8.3.3. ConstraintsonEncoding
NALStructuredVideostreamsconformingtothisMediaProfile: SHALLhavethefollowingpre‐determinedvalues:
transfer_characteristicsSHALLbesetto16forthereferenceelectro‐optictransferfunctionspecifiedin[SMPTE‐2084].
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AnnexC.DeliveryTargets
C.1. GeneralDownloadDeliveryTargetConstraints
C.1.1. Constraints on File Structure
DCCsconformingtoaDownloadDeliveryTargetSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection2,TheCommonFileFormat,withtheadditionalconstraintsdefinedasfollows:
TheDCCMovieFragmentSHALLcontainoneMediaDataBox(‘mdat’).
C.1.2. Constraints on Video
DCCsconformingtoaDownloadDeliveryTargetSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection4,VideoElementaryStreams,withtheadditionalconstraintsdefinedasfollows:
ForeachVideotrackthefollowingrequirementsapply: VideotrackMovieFragmentsSHALLstartwithSAPtype1or2. Videotracksutilizing(‘avc1’)sampleentriesasdefinedinSection4.3.1.1:everyAVC
videotrackfragmentSHALLcontainaTrickPlayBox(‘trik’). VideotrackswhichhaveoneormoreFragmentswithadurationgreaterthan3.003secs
andutilize(‘avc3’)sampleentriesasdefinedinSection4.3.1.1SHALLbesignaledintheTrackFragmentBox('traf')usingRandomAccessPoint(RAP)samplegroupingasdefinedin[ISO]Section10.4,withthefollowingadditionalconstraints: AllsyncsamplesSHALLbesignaledinaSampletoGroupBox(‘sbgp’)withthe
followingconstraints:o grouping_type:setto'rap 'o group_description_indexforthesyncsample:correspondstoa
VisualRandomAccessEntry intheSampleGroupDescriptionBox(‘sgpd’)withthefollowingfieldvalues
o num_leading_samples_known=1 o num_leading_samples=0
AllAVCRA‐Isamples(definedinSection4.2.6)SHALLbesignaledinaSampletoGroupBox(‘sbgp’)withthefollowingconstraints:
o grouping_type:setto'rap 'o group_description_indexfortheRAIsample:correspondstoa
VisualRandomAccessEntry intheSampleGroupDescriptionBox(‘sgpd’)withthefollowingfieldvalues
o num_leading_samples_known=1 o num_leading_samples=numberof“leadingsamples” o Notethata“leadingsample”inRAPSampleGroupingisdefinedasa
samplethatprecedestheRAPinpresentationorderand
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immediatelyfollowstheRAPoranotherleadingsampleindecodingorder,andcannotbecorrectlydecodedwhendecodingstartsfromtheRAP.
Videotrackswhichutilize(‘hev1’)sampleentriesasdefinedinSection4.4.1.1SHALLsignalTypeofsyncsamplesusingsyncsamplesamplegroupingasdefinedin[ISOVIDEO]Section8.4.4.
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C.2. Multi‐TrackDownloadDeliveryTarget
C.2.1. Overview
TheMulti‐TrackDownloadDeliveryTargetisintendedforapplicationswhereastandaloneDCCismadeavailablefordownloaddelivery.TheMulti‐TrackDownloadDeliveryTargetisdefinedbythe‘cfd1’brand,whichisacodepointontheISOBaseMediaFileFormatdefinedby[ISO].
C.2.2. Constraints on File Structure
DCCsconformingtothisDeliveryTargetSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexC.1.1withtheadditionalconstraintsdefinedasfollows:
TheFileTypeBox(‘ftyp’)SHALLlistthe‘cfd1’brandasacompatible_brand.
TheMetadataBox(‘meta’)containedintheMovieBox(‘moov’)forRequiredMulti‐TrackMetadataasdefinedinSection2.1.2.1SHALLbepresentintheDCC.
AFreeSpaceBox(‘free’)SHALLbethelastboxintheMovieBox(‘moov’).Note:thisprovidesreservedspaceforaddingDRM‐specificinformation.
TheDCCFooterSHALLcontainaMovieFragmentRandomAccessBox(‘mfra’).
C.2.3. Constraints on Encryption
C.2.3.1. ConstraintsonPDandSDMediaProfileEncryption
DCCsconformingtothisDeliveryTargetandthePDMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.1.2withtheadditionalconstraintsdefinedinthisSection.DCCsconformingtothisDeliveryTargetandSDMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.2.2withtheadditionalconstraintsdefinedinthisSection.
AllencryptedaudiotracksintheDCCSHALLbeencryptedusingthesamekey(“audiokey”). AllencryptedvideotracksintheDCCSHALLbeencryptedusingthesamekey(“videokey”). ThevideokeyandaudiokeySHALLbethesamekey.
C.2.3.2. ConstraintsonHDMediaProfileEncryption
DCCsconformingtothisDeliveryTargetandtheHDMediaProfileSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.3.2withtheadditionalconstraintsdefinedinthisSection.
AllencryptedaudiotracksintheDCCSHALLbeencryptedusingthesamekey(“audiokey”). AllencryptedvideotracksintheDCCSHALLbeencryptedusingthesamekey(“videokey”). ThevideokeySHOULDbeseparate(independentlychosen)fromtheaudiokey.
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C.2.3.3. ConstraintsonxHD,UHD,DV,HDR10andHDR12MediaProfileEncryption
DCCsconformingtothisDeliveryTargetandthexHD,UHD,DV,HDR10andHDR12MediaProfilesSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexB.4.2withtheadditionalconstraintsdefinedinthisSection.
AllencryptedaudiotracksintheDCCSHALLbeencryptedusingthesamekey(“audiokey”). videokeysSHOULDbeseparate(independentlychosen)fromtheaudiokey.
C.2.4. Constraints on Video
C.2.4.1. Overview
DCCsconformingtothisDeliveryTargetshallcomplywithalloftherequirementsandconstraintsdefinedinAnnexC.1.2withtheadditionalconstraintsdefinedasfollows:
DCCsSHALLcontainexactlyonevideotrack,andthatvideotrackSHALLconformtoSection4. AvideotrackfragmentSHALLhaveadurationnogreaterthan3.003seconds.
C.2.4.2. ConstraintsonSequenceParameterSets(SPS)
Theconditionofthefollowing[H264]fieldsSHALLNOTchangethroughoutanAVCVideotrackconformingtothisDeliveryTarget:
pic_width_in_mbs_minus1
pic_height_in_map_units_minus1Theconditionofthefollowing[H265]fieldsSHALLNOTchangethroughoutanHEVCVideotrackconformingtothisDeliveryTarget:
pic_width_in_luma_samples
pic_height_in_luma_samples
C.2.4.2.1. ConstraintsonVisualUsabilityInformation(VUI)ParametersTheconditionofthefollowingSHALLNOTchangethroughoutAVCVideotracksconformingtothisDeliveryTarget:
aspect_ratio_idc Bitrate[](calculatedbybit_rate_scaleandbit_rate_value_minus1)
CpbSize[](calculatedbycpb_size_scaleandcpb_size_value_minus1)TheconditionofthefollowingSHALLNOTchangethroughoutHEVCVideotracksconformingtothisDeliveryTarget:
aspect_ratio_idc
aspect_ratio_idc
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cpb_cnt_minus1 bit_rate_scale bit_rate_value_minus1 cpb_size_scale
cpb_size_value_minus1
C.2.4.3. ConstraintsonPictureFormats
C.2.4.3.1. OverviewTheMediaProfiledefinitionsinAnnexBdefinepermittedpictureformats.ThisSectionprovidesmoredetailonpermittedpictureformatsperMediaProfileforDownloadDeliveryTargets.Constraintsaredefinedintheformofframesizeandframerate.
Framesizeisdefinedasthemaximumdisplaywidthandheightofthepictureinsquarepixelsaftercroppingandsubsamplerescalingisapplied.Foreachpictureformatdefined,oneormoreallowedvaluecombinationsarespecifiedforhorizontalandverticalsub‐samplefactors,whicharenecessaryforselectingvalidTrackHeaderBoxwidthandheightproperties,asspecifiedinSection2.3.5andSection4.2.1.
Whensub‐samplingisapplied,atleastoneofeitherthewidthortheheightoftheencodedpicturesizeSHALLmatchthevaluespecifiedinthe“MaxSizeEncoded”columninthefollowingTables.SeeSection4.5formoreinformation.
Framerateisdefinedasaratiocorrespondingtoarealnumber.ThisnumberSHALLprecisely(withnoroundingerrorpermitted)matchthevaluecalculatedperSection4.3.2.5andSection4.4.2.7).
aspect_ratio_idcSHALLbeencodedaslistedorsetto255andExtended_SARprovidedtomatchtheaspectratiodefined.
C.2.4.3.2. ConstraintsonPDMediaProfilePictureFormatsNALStructuredVideostreamsconformingtothePDMediaProfile(seeAnnexB.1)andthisDeliveryTargetSHALLcomplywiththepictureformatconstraintslistedbelow.
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TableC‐1–PictureFormatsandConstraintsofPDMediaProfilefor24Hz&30HzContentPictureFormats Sub‐sampleFactors EncodingParameters
Framesize(widthxheight)
Pictureaspect
Framerate Horiz. Vert. Max.sizeencoded
aspect_ratio_idc
320x180 1.778
24000÷1000,24000÷1001,30000÷1000,30000÷1001
1 1 320x180 1
320x240 1.333
24000÷1000,24000÷1001,30000÷1000,30000÷1001
1 1 320x240 1
416x240(Note) 1.733
24000÷1000,24000÷1001,30000÷1000,30000÷1001
1 1 416x240 1
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TableC‐2–PictureFormatsandConstraintsofPDMediaProfilefor25HzContentPictureFormats Sub‐sampleFactors EncodingParametersFramesize(widthxheight)
Pictureaspect
Framerate Horiz. Vert. Max.sizeencoded
aspect_ratio_idc
320x180 1.778 25000÷1000 1 1 320x180 1
320x240 1.333 25000÷1000 1 1 320x240 1
416x240(Note) 1.733 25000÷1000 1 1 416x240 1
Note:The416x240framesizecorrespondstoa15.6:9pictureaspectratio.RecommendationsforpreparingcontentinthisframesizeareavailableinSection6“VideoProcessingbeforeAVCCompression”of[ATSC].
C.2.4.3.3. ConstraintsonSDMediaProfilePictureFormatsNALStructuredVideostreamsconformingtotheSDMediaProfile(seeAnnexB.2)andthisDeliveryTargetSHALLcomplywiththepictureformatsconstraintslistedbelow.TableC‐3–PictureFormatsandConstraintsofSDMediaProfilefor24Hz,30Hz&60HzContentPictureFormats Sub‐sampleFactors EncodingParametersFramesize(widthxheight)
Pictureaspect
Framerate Horiz. Vert. Max.sizeencoded
aspect_ratio_idc
sar_width sar_height
640x480 1.333
24000÷1000,24000÷1001,30000÷1000,30000÷1001
1.1 1 704x480 3 ‐ ‐1 1 640x480 1 ‐ ‐0.75 1 480x480 14 ‐ ‐0.75 0.75 480x360 1 ‐ ‐0.5 0.75 320x360 15 ‐ ‐
640x480 1.33360000÷1000,60000÷1001
464/640 0.75 464x360 255 30 29
0.5 0.75 320x360 15 ‐ ‐
854x480
1.778
24000÷1000,24000÷1001
1 1 854x480 1 ‐ ‐704/854 1 704x480 5 ‐ ‐640/854 1 640x480 14 ‐ ‐640/854 0.75 640x360 1 ‐ ‐426/854 0.75 426x360 15 ‐ ‐
854x480
1.778
30000÷1000,30000÷1001
704/854 1 704x480 5 ‐ ‐640/854 1 640x480 14 ‐ ‐640/854 0.75 640x360 1 ‐ ‐426/854 0.75 426x360 15 ‐ ‐
854x480 1.778 60000÷1000,60000÷1001
426/854 0.75 426x360 15 ‐ ‐
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TableC‐4–PictureFormatsandConstraintsofSDMediaProfilefor25Hz&50HzContentPictureFormats Sub‐sampleFactors EncodingParametersFramesize(widthxheight)
Pictureaspect
Framerate Horiz. Vert. Max.sizeencoded
aspect_ratio_idc
sar_width sar_height
640x480 1.333 25000÷1000
1.1 1.2 704x576 2 ‐ ‐1 1 640x480 1 ‐ ‐0.75 1 480x480 14 ‐ ‐0.75 0.75 480x360 1 ‐ ‐0.5 0.75 320x360 15 ‐ ‐
640x480 1.333 50000÷10000.75 0.75 480x360 1 ‐ ‐
0.5 0.75 320x360 15 ‐ ‐
854x480 1.778 25000÷1000
1 1 854x480 1 ‐ ‐704/854 1.2 704x576 4 ‐ ‐640/854 1 640x480 14 ‐ ‐640/854 0.75 640x360 1 ‐ ‐426/854 0.75 426x360 15 ‐ ‐
854x480 1.778 50000÷1000560/854 0.75 560x360 255 9 8426/854 0.75 426x360 15 ‐ ‐
C.2.4.3.4. ConstraintsonHDandxHDMediaProfilePictureFormatsNALStructuredVideostreamsconformingtotheHDMediaProfile(seeAnnexB.3)andxHDMediaProfile(seeAnnexB.4)andthisDeliveryTargetSHALLcomplywiththepictureformatconstraintslistedbelow.TableC‐5–PictureFormatsandConstraintsofHDandxHDMediaProfilefor24Hz,30Hz&60Hz
ContentPictureFormats Sub‐sampleFactors EncodingParametersFramesize(widthxheight)
Pictureaspect
Framerate Horiz. Vert. Max.sizeencoded
aspect_ratio_idc
1280x720 1.778
24000÷1000,24000÷1001,30000÷1000,30000÷1001,60000÷1000,60000÷1001
1 1 1280x720 1
0.75 1 960x720 14
0.5 1 640x720 16
1920x1080
1.778
24000÷1000,24000÷1001,30000÷1000,30000÷1001
1 1 1920x1080 1
0.75 1 1440x1080 14
0.75 0.75 1440x810 1
0.5 0.75 960x810 15
TableC‐6–PictureFormatsandConstraintsofHDandxHDMediaProfilefor25Hz&50HzContent
PictureFormats Sub‐sampleFactors EncodingParametersFramesize(widthxheight)
Pictureaspect
Framerate Horiz. Vert. Max.sizeencoded
aspect_ratio_idc
1280x720 1.77825000÷1000,50000÷1000
1 1 1280x720 1
0.75 1 960x720 14
0.5 1 640x720 16
1920x1080
1.778
25000÷1000
1 1 1920x1080 1
0.75 1 1440x1080 14
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0.5 0.75 960x810 15
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C.2.4.3.5. ConstraintsonUHDMediaProfilePictureFormatsNALStructuredVideostreamsconformingtotheUHDMediaProfile(seeAnnexB.5)andthisDeliveryTargetSHALLcomplywiththepictureformatconstraintslistedbelow.TableC‐7–PictureFormatsandConstraintsofUHDMediaProfilefor24Hz,30Hz&60HzContent
PictureFormats Sub‐sampleFactors EncodingParametersFramesize(widthxheight)
Pictureaspect
Framerate Horiz. Vert. Max.sizeencoded
aspect_ratio_idc
3840x2160
1.778
24000÷1000,24000÷1001,30000÷1000,30000÷1001,48000÷1000,60000÷1000,60000÷1001
1 1 3840x2160 1
0.75 1 2880x2160 14
0.75 0.75 2880x1620 1
0.5 0.75 1920x1620 15
TableC‐8–PictureFormatsandConstraintsofUHDMediaProfilefor25Hzand50HzPictureFormats Sub‐sampleFactors EncodingParametersFramesize(widthxheight)
Pictureaspect
Framerate
Horiz.
Vert.
Max.sizeencoded
aspect_ratio_idc
3840x2160
1.778
25000÷1000,50000÷1000
1 1 3840x2160 1
0.75 1 2880x2160 14
0.75 0.75 2880x1620 1
0.5 0.75 1920x1620 15
C.2.4.3.6. ConstraintsonHDR10andHDR12MediaProfilePictureFormatsNALStructuredVideostreamsconformingtotheHDR10(seeAnnexB.6)orHDR12(seeAnnexB.8)MediaProfilesandthisDeliveryTargetSHALLcomplywiththepictureformatconstraintslistedbelow.
PictureFormatsandConstraintsofHDR10MediaProfilefor24Hz,30Hz&60HzContent:seeTableC‐5andTableC‐7.
PictureFormatsandConstraintsofHDR10MediaProfilefor25Hz&50HzContent:seeTableC‐6andTableC‐8.
C.2.5. Constraints on Audio
DCCsconformingtothisDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinSection5,AudioElementaryStreams,withtheadditionalconstraintsdefinedhere.
ADCCSHALLcontainatleastoneMPEG‐4AAC[2‐Channel]audiotrack. ADCCSHALLNOTcontainmorethan32audiotracks. ADCCwithavideotrackwhichcomplieswiththeSDMediaProfileSHALLonlycontainaudiotracks
thatcorrespondwithTableB‐4“AllowedAudioFormatsinSDMediaProfile”.
C.2.6. Constraints on Subtitles
DCCsconformingtothisDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinSection6,SubtitleElementaryStreamswiththefollowingadditionalconstraints:
TheassociatedvideotrackSHALLbethevideotrackintheDCC.
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ADCCMAYcontainzeroormoresubtitletracks,butSHALLNOTcontainmorethan255subtitletracks.
ThedurationofasubtitletrackSHALLNOTexceedthedurationofthelongestaudioorvideotrackintheDCC.
AsubtitletrackfragmentMAYhaveadurationuptothedurationofthelongestaudioorvideotrackintheDCC.
Asubtitletrack’sTrackHeaderBox(‘tkhd’)SHALLhavethesamewidthandheightvaluesasTrackHeaderBox(‘tkhd’)forthevideotrackintheDCC.
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C.3. Single‐TrackDownloadDeliveryTarget
C.3.1. Overview
TheSingle‐TrackDownloadDeliveryTargetisintendedtobeusedtogetherwith[DDMP]tosupportapplicationswhereaDCCismadeavailablefordownloaddeliveryaspartofaPresentationdefinedwithinaCommonMediaPackage:
UnliketheMulti‐TrackDCCsdefinedinAnnexC.2,aSingle‐TrackDCCisintendedtobeplayedtogethersimultaneouslywithotherSingle‐TrackDCCs.
A“Presentation”isasetofsingle‐trackDCCsthatareintendedtobeplayedtogether. Single‐trackDCCsandPresentationsfollowmostoftheencodingconstraintsofatrackinaMulti‐
TrackDCC(asdefinedinAnnexC.2)exceptwhereCommonMediaPackagemetadataisutilizedforequivalentfunctionality,suchasmetadatastorageandtrackdescriptionasdefinedin[DDMP].
See[DDMP]formoreinformationontheCommonMediaPackageandPresentations.TheSingle‐TrackDownloadDeliveryTargetisdefinedbythe‘cfd2’brand,whichisacodepointontheISOBaseMediaFileFormatdefinedby[ISO].
C.3.2. Constraints on File Structure
DCCsconformingtothisDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinAnnexC.1.1withtheadditionalconstraintsdefinedasfollows:
TheFileTypeBox(‘ftyp’)SHALLlistthe‘cfd2’brandasacompatible_brand. TheDCCSHALLcontainoneandonlyoneISOMediatrack. RequiredMulti‐TrackMetadata,asdefinedinSection2.1.2,andOptionalMulti‐TrackMetadata,as
definedinSection2.1.4,SHOULDNOTbepresent. AFreeSpaceBox(‘free’)SHOULDNOTbepresent.
TheDCCFooterSHALLcontainaMovieFragmentRandomAccessBox(‘mfra’).
C.3.3. Constraints on Encryption
DCCsconformingtothisDeliveryTargetSHALLcomplywiththeadditionalconstraintsdefinedinthisSection.
AllvideokeysSHOULDbeseparate(independentlychosen)fromaudiokeys.
C.3.4. Constraints on Video
Single‐TrackVideoDCCsconformingtothisDeliveryTargetSHALLcomplywiththevideoconstraintsdefinedinAnnexC.2.4withtheadditionalconstraints/exceptionsdefinedasfollows:
AVCVideotracksSHALLutilizethe(‘avc3’)in‐bandsampleentriesasperSection4.3.1.1.
C.3.5. Constraints on Audio
Single‐TrackAudioDCCsconformingtothisDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinSection5,AudioElementaryStreams.
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APresentationutilizingthisDeliveryTargetSHALLcontainatleastoneMPEG‐4AAC[2‐Channel]audiotrack.
C.3.6. Constraints on Subtitles
Single‐TrackSubtitleDCCsconformingtothisDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinSection6,SubtitleElementaryStreamswiththefollowingadditionalconstraints.
TheassociatedvideotrackSHALLbethevideotrackcontainedinthesamePresentationasthesubtitletrack.
Ifthesubtitletrack’sTrackHeaderBox(‘tkhd’)widthandheightvaluesarenon‐zero,thewidthorheightorbothwidthandheightSHOULDmatchtheassociateddimensiondefinedfor“FrameSize”inoneofthePictureFormatslistedinAnnexC.2.4.3.
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C.4. Pre‐PackagedDeliveryTarget
C.4.1. Overview
ThePre‐PackagedDeliveryTargetisintendedtobeusedtogetherwith[DDMP]tosupportapplicationswhereasingle‐trackDCCismadeavailablewithpre‐packageddeliveryaspartofaPresentationdefinedwithinaCommonMediaPackage;pre‐packageddeliverymeansthatthecontentisdeliveredincompleteforme.g.onanopticaldisc.DCCsconformingtothisDeliveryTargetSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexC.3exceptasdefinedbelow.ThePre‐PackagedDCCDeliveryTargetisdefinedbythe‘cfd3’brand,whichisacodepointontheISOBaseMediaFileFormatdefinedby[ISO].
C.4.2. Constraints on File Structure
DCCsconformingtothisDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinAnnexC.3.2withtheadditionalconstraintsandexceptionsdefinedasfollows:
TheFileTypeBox(‘ftyp’)SHALLlistthe‘cfd2’brandasacompatible_brandonlyifallrequirementsdefinedinAnnexC.3aresatisfied.
TheFileTypeBox(‘ftyp’)SHALLlistthe‘cfd3’brandasacompatible_brand.
TheDCCHeaderSHALLcontainoneSegmentIndexBox(‘sidx’).ThesampleatthestartofeachMovieFragmentSHALLbesignaledintheSegmentIndexBox(‘sidx’).
C.4.3. Constraints on Video
Single‐TrackVideoDCCsconformingtothisDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinAnnexC.3.4withtheadditionalconstraintsandexceptionsdefinedasfollows:
VideotrackMovieFragmentsSHALLstartwithSAPtype1,2,or3.
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C.5. StreamingDeliveryTarget
C.5.1. Overview
TheStreamingDeliveryTargetisintendedtobeusedtogetherwith[DStream]tosupportapplicationswhereasingle‐trackDCCismadeavailableforstreamingdeliveryaspartofanAdaptationSetwithina[DASH]MediaPresentationDescription:
UnliketheSingle‐TrackDCCsdefinedinAnnexC.3andC.4,aStreamingDCCisintendedtobeoneofseveralDCCsinan“AdaptationSet”.
An“AdaptationSet”isasetofsingle‐trackDCCsthatareinterchangeableencodedversionsofthesameContentwhichareseamlesslyswitchablein[DASH]adaptivestreamingapplications.
“SeamlesslySwitchable”meansdifferentMovieFragmentscanbeselectedinsequencefromdifferentDCCswithoutpresentationerrors.
A“MediaPresentationDescription”definesAdaptationSetsthatareintendedtobeplayedtogether(similartoaPresentationasdefinedinAnnexC.3).
See[DStream]formoreinformationontheAdaptationSetsandMediaPresentationDescriptions.TheStreamingDCCDeliveryTargetisdefinedbythe‘cfd4’brand,whichisacodepointontheISOBaseMediaFileFormatdefinedby[ISO].
C.5.2. Constraints on File Structure
DCCsconformingtoaStreamingDeliveryTargetSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection2,TheCommonFileFormat,withadditionalconstraintsdefinedasfollows:
TheFileTypeBox(‘ftyp’)SHALLlistthe‘cfd4’brandasacompatible_brand.
TheDCCMovieFragmentSHALLcontainoneMediaDataBox(‘mdat’). TheDCCSHALLcontainoneandonlyoneISOMediatrack. TheSegmentIndexBox(‘sidx’),ifpresent,SHALLcomplywithSection2.3.21and[DASH]
Section6.3.4.
C.5.3. Constraints on Encryption
DCCsconformingtothisDeliveryTargetSHALLcomplywithadditionalconstraintsdefinedinthisSection. AllencryptedaudiotrackslistedbyaPeriodina[DStream]MPDSHOULDbeencryptedusingthe
samekey(“audiokey”).SeealsoAnnexC.5.7“ConstraintsonAdaptionSets". AllencryptedvideotrackslistedbyaPeriodina[DStream]MPDSHOULDbeencryptedusingthe
samekey(“videokey”).SeealsoAnnexC.5.7“ConstraintsonAdaptionSets". AllvideokeysSHOULDbeseparate(independentlychosen)fromtheaudiokeys.
C.5.4. Constraints on Video
C.5.4.1. Overview
DCCsconformingtoaStreamingDeliveryTargetSHALLcomplywithalloftherequirementsandconstraintsdefinedinSection4,VideoElementaryStreams,withadditionalconstraintsdefinedasfollows:
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DCCsSHALLcontainexactlyonevideotrack,andthatvideotrackSHALLconformtoSection4. AVCVideotracksSHALLutilizethe(‘avc3’)in‐bandsampleentriesasperSection4.3.1.1. VideotrackMovieFragmentsSHALLstartwithSAPtype1or2. negativecompositionoffsetsintheTrackRunBox(‘trun’)(seeSection2.4)SHALLbeusedto
synchronizethecompositiontimesofvideosamplestothedecodetimeofothertrackssothateachsampleisframeaccuratelysynchronizedtothemovieand[DASH]MPDpresentationtimeline.Note:useofnegativecompositionoffsetsprovidesamechanismtomatchthepresentationtimeofthefirstvideoframetothedecodetimeofMovieFragments,andpreventsgapsoroverlapsinsamplepresentationtimeswhenswitchingbetween[DStream]Representationswithdifferentcompositionoffsetsduetodifferentnumbersofpicturesinthedecodedpicturebuffernecessarytodecodeandpresentthefirstvideoframe.[DStream]MPDs,SegmentIndexBox(‘sidx’)indexes,andSegmentaddressesarebasedonthepresentationtimelineofthemedia,butDCCMovieFragmentsarestoredandtimestampedwithdecodetime.
C.5.4.2. ConstraintsonPictureFormats
VideotracksconformingtothisDeliveryTargetMAYutilizedynamicsubsamplingofeachCodedVideoSequencewithinaDCCMovieFragmentbyallowingdifferentencodedhorizontalandverticalvideospatialsamplecountsineachCodedVideoSequence(seeSection4.5.4).Note:DynamicsubsamplingwithinaCSFfileisnormallyusedtoreducevideobitratepeaksandmaintainconsistentMediaSegmentsize.Note:NALStructuredVideoparametersetspreventtheneedtoinsertanInitializationSegmentpriortoeachMediaSegmentincasethedecodingparameterschangeduetodynamicsubsamplingoradaptiveswitchingbetweenDCCs([DASH]Representations);theparametersetsprovidetheinformationnecessaryfordisplaysystemstoscaleeachCodedVideoSequencetoacommondisplayresolutionandposition.
C.5.5. Constraints on Audio
Single‐TrackAudioDCCsconformingtoaStreamingDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedininSection5,AudioElementaryStreams.A[DStream]MPDutilizingthisDeliveryTargetSHALLcontainatleastoneMPEG‐4AAC[2‐Channel]audiotrack.
C.5.6. Constraints on Subtitles
Single‐TrackSubtitleDCCsconformingtoaStreamingDeliveryTargetSHALLcomplywiththerequirementsandconstraintsdefinedinSection6,SubtitleElementaryStreamswithadditionalconstraintsdefinedasfollows:
TheassociatedvideotrackSHALLbethevideotrackcontainedinthesamePeriodasthesubtitletrack.
Ifthesubtitletrack’sTrackHeaderBox(‘tkhd’)widthandheightvaluesarenon‐zero,thewidthorheightorbothwidthandheightSHOULDmatchtheassociateddimensiondefinedfor“FrameSize”inoneofthePictureFormatslistedinAnnexC.2.4.3.
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C.5.7. Constraints on Adaptation Sets
AdaptationSetsconformingtothisDeliveryTargetSHALLcomplywithalloftherequirementsandconstraintsdefinedin[DStream]withtheadditionalconstraintsdefinedasfollows:
AllencryptedaudiotrackswithinanAdaptionSetSHALLusethesamekey;and AllencryptedvideotrackswithinanAdaptionSetSHALLusethesamekey.;and AllvideotracksinthesameAdaptionSetSHALLhavematchingSampleEntrytype;and AllDCCAdaptationSetsina[DStream]MPDPeriodSHALLhavethesameMovieHeaderBox
(‘mvhd’)timescalevalue;and Note:Fora[DStream]Presentation,theMovieHeaderBox(‘mvhd’)timescaleis
appliedtotheentire[DASH]PresentationPeriod,whichisanindependenttimespanwithinthePresentation.ThistimescalevalueisindependentofthetracktimescaleintheMediaHeaderBox(‘mdhd’),whichisspecifictothemediainthecontainingtrack,andshouldbedifferentfordifferentmediasamplefrequenciesinthesamePeriod.
AllDCCsinthesameAdaptationSethavematchingTrackHeaderBox(‘tkhd’)fieldsasfollows: thevaluesofwidthandheightfieldsSHALLmatch;and thevaluesofthetimescalefieldSHALLmatch;and thevaluesofthetrack_IDfieldSHALLmatch;and
AllDCCsinthesameAdaptationSetSHALLhavethesamedefault_KIDvaluefortheTrackEncryptionBox(‘tenc’)ifthetrackisencrypted;and
AllDCCsinthesameAdaptationSetSHALLbe“timealigned”i.e.allDCCsinthesameAdaptationSetSHALLhavematchingtrackfragmentdurationsforallMovieFragmentswiththesamebaseMediaDecodeTimeandMovieFragmentsequence_number;and
AllDCCsinthesameAdaptationSetSHALLbe“spatiallyaligned”i.e.allencodedandcroppedsamplecountsSHALLbeexactratiosoftheNormalizedDisplayWidthandNormalizedDisplayHeight;and
AllDCCsinaGroupofAdaptationSetsMAYusethesametrack_IDvaluetoidentifyallDCCsandAdaptationSetsintheGroupi.e.[DStream]AdaptationSet@groupattributeinMPD=track_IDinthe‘tkhd’,‘trex’,and‘tfhd’boxes);and
[DStream]AdaptationSet@groupattributeSHALLfollowtheassignmentinTableC‐7.TableC‐9–[DStream]GroupAssignment
[DStream]Group TrackType1 PrimaryVideo2 SecondaryVideo5 MainAudio6 SecondaryAudio7 TertiaryAudio3 MainSubtitle4 SecondarySubtitle8 Other
Note:AnyDCCfileheaderintheAdaptationSetfollowedbyacontinuousandorderedsequenceofmoviefragmentsfromthatDCCoraDCCintheAdaptationSetwithlowervideocodecLevel,Profile,andTierwillformavalidDCCandthereforeconformto@bitstreamSwitching=”true”per[DASH].A
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singleinitializationofaplayer’svideoparsing,decryption,decoding,andpresentationsystemissufficienttopresentmoviefragmentsselectedfromthatsubsetoftheAdaptationSet.
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AnnexD.InternetMediaTypeTemplateandParameters
TheMediaTypesignalingdefinedinthisSectionSHALLbeusedwhendeliveringDCCs. MediaTypeTemplate:SHALLbesetto“video/vnd.dece.mp4”. MediaTypeParameters:
profiles:SHALLlistallISObrandssignaledintheFileTypeBox(‘ftyp’)inaccordancewith[RFC6381]Section4.
profile-level-idc:SHALLlistthe[MP4RA]fourcharactercodewiththeMediaProfileofeachtrackinacommaseparatedlist,inascendingtrack_idorder.TheMediaProfileofthetrackisdefinedasfollows. Videotrack:SHALLdefinetheMediaProfileassociatedwiththeVideotrack. Audiotrack:SHALLsignalthelowestMediaProfilesupportedbytheAudiotrack
andtheEcosystem(s)inwhichthefilewillbeused.Forexample,aDCCtobeusedinanecosystemwhichsupportstheSDMediaProfileasthelowestMediaProfilewoulduse'cfsd'forastereoAACaudiotrack;thatsametrackwoulduse'cfpd'ifusedinanEcosysteminwhichthePortableDefinitionMediaProfileissupported.
Subtitletrack:SHALLsignaltheMediaProfileassociatedwiththeSubtitletrackasfollows: IftheSubtitletrackhasanyCFF‐TTdocumentthathasbeenauthoredfora
specificMediaProfileorsetofMediaProfiles,thelowestMediaProfilesupportedbytheSubtitletrackSHALLbesignaled. Note:CFF‐TTdocumentsareauthoredforaspecificMediaProfileif
theyconformtotheCFF‐TTImagebasedProfile,oriftheyconformtoCFF‐TTTextbasedProfileandoneormoreofthesedocumentsusesscalarlengthattributes.
IftheSubtitletrackcontainsCFF‐TTdocumentsthathaveallbeenauthoredtobeMediaProfileindependentthenthe‘cfad’coderegisteredwith[MP4RA]SHALLbesignalled. Note:CFF‐TTdocumentscanbeMediaProfileindependentifthey
conformtotheCFF‐TTTextbasedProfile,noscalarlengthattributesareusedandtheperformanceconstraintsdefinedinAnnexB.1.5arenotexceeded.
codecs:SHALLlisteachtrack,inascendingtrack_idorder,inaccordancewith[RFC6381]Section3.3.The[MP4RA]codecscodepointSHALLbeusedforvideoandaudiotracks.“cfft”SHALLbeusedforCFF‐TTtracksutilizingtheTextProfile(seeSection6.2.3.4)and“cffi”SHALLbeusedforCFF‐TTtracksutilizingtheImageProfile(seeSection6.2.3.5).
protection: SHALLlistwhichprotectionschemeappliestoeachtrack,inascendingtrack_idorderinacommaseparatedlist,usingthe[MP4RA]fourcharactercoderegisteredprotectionschemevalueor‘none’toindicatethatthetrackisnotprotected.
languages:SHALLlisttheassociatedlanguageofalltracks,inascendingtrack_idorderinacommaseparatedlist,inaccordancewith[RFC5646].ThevideotracklanguageSHOULDrepresenttheoriginalreleaselanguageofthecontent.
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AnnexE.TheDECEFileFormat
TheDECEFileFormatisbasedontheCommonFileFormat,withenhancementstosupporttheDECEEcosystem.See[DSystem]formoreinformationontheDECEEcosystem.
E.1. DECEFileFormat
ThisSectiondefinesanadaptionoftheCommonFileFormatfortheDECEEcosystem.TheDECEFileFormatisdefinedbythe‘uvvu’brand,whichisacodepointontheISOBaseMediaFileFormatdefinedby[ISO].Thebrand‘uvvu’SHALLincorporatesupportforallfeaturesofthe‘ccff’branddefinedinSection2withadditionalrequirementsdefinedinthisAnnex.
E.1.1. Extensions to the Common FileFormat
TheSectiondefinesadditionalboxesthatSHALLbesupportedbythebrand‘uvvu’inadditiontotheboxesrequiredbythe‘ccff’brand.
TableD‐1–AdditionalBoxesoftheDECEFileFormatNL0 NL1 NL2 NL3 NL4 NL5 FormatReq. Specification Descriptionbloc 0/1 AnnexE.1.1.1 BaseLocationBox ainf 0/1 AnnexE.1.1.2 AssetInformationBox
FormatReq.:Numberofboxesrequiredtobepresentinthecontainer,where‘*’means“zeroormore”and‘+’means“oneormore”.Avalueof"0/1"indicatesonlythataboxmightormightnotbepresentbutdoesnotstipulatetheconditionsofitsappearance.
E.1.1.1. BaseLocationBox(‘bloc’)
BoxType ‘bloc’
Container FileMandatory NoQuantity ZeroorOneTheBaseLocationBoxisafixed‐sizeboxthatcontainstheBaseLocationandPurchaseLocationstringsnecessaryforlicenseacquisition,asdefinedinSections8.3.2and8.3.3of[DSystem].TheBaseLocationBox(‘bloc’),ifpresentintheDCC:
SHOULDimmediatelyfollowtheFileTypeBox(‘ftyp’)intheDCCHeader;and
SHALLappearbeforetheMovieBox(‘moov’).
E.1.1.1.1. Syntaxaligned(8) class BaseLocationBox extends FullBox(‘bloc’, version=0, flags=0) { byte[256] baseLocation; byte[256] basePurlLocation; // optional byte[512] reserved = 0; }
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E.1.1.1.2. Semantics baseLocation–SHALLcontaintheBaseLocationdefinedinSection8.3.2of[DSystem],followed
bynullbytes(0x00)toalengthof256bytes. basePurlLocation–optionallydefinestheBasePurlLocationasspecifiedinSection8.3.3of
[DSystem],followedbynullbytes(0x00)toalengthof256bytes.IfnoBasePurlLocationisdefined,thisfieldSHALLbefilledwithnullbytes(0x00).
Reserved–Reservespaceforfutureuse.ImplementationsconformantwiththisspecificationSHALLignorethisfield.
E.1.1.2. AssetInformationBox(‘ainf’)
TheAssetInformationBox(‘ainf’)SHOULDNOTbeused.Itisprovidedforbackwardscompatibilitywithpreviousreleasesofthisspecification.TheContentInformationBox(‘coin’)definedinSection2.2.2replacestheusetheAssetInformationBox(‘ainf’).BoxType ‘ainf’
Container MovieBox(‘moov’)Mandatory YesQuantity ZeroorOneTheAssetInformationBox(‘ainf’)containsfileinformationtoidentify,licenseandplaycontentwithintheDECEecosystem.TheAssetInformationBox(‘ainf’),ifpresentintheDCC:
SHOULDimmediatelyfollowtheContentInformationBox(‘coin’)intheDCCHeader;and
SHALLappearbeforetheMovieBox(‘moov’).
E.1.1.3. Syntax
aligned(8) class AssetInformationBox extends FullBox(‘ainf’, version=0, flags) { int(32) profile_version; string APID; Box other_boxes[]; // optional }
E.1.1.4. Semantics
flags –24‐bitintegerdefinedasfollows:hidden: whensetindicatesthatfileshouldnotbevisibletotheuser.Flagvalueis
‘0x000001’. profile_version–indicatestheMediaProfiletowhichthiscontainerfileconforms.Themost
significant8bitsdesignatetheprofile(PD,SD,HD,etc.)asdefinedintheAnnexesofthisspecification.Theleastsignificant24bitsSHALLbesettothe[UNICODE]UTF‐8representationofthisDMediaSpecificationasdefinedinAnnexA.,DMEDIA_VERSION_NOPOINTS.
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APID–indicatestheAssetPhysicalIdentifier(APID)ofthiscontainerfile,asdefinedinSection5.5.1“AssetIdentifiers”of[DSystem].
other_boxes –Availableforprivateandfutureuse.
E.1.2. Constraints on ISOBase Media File Format Boxes
E.1.2.1. FileTypeBox(‘ftyp’)
DCCsconformingtotheDECEFileFormatSHALLincludeaFileTypeBox(‘ftyp’)asspecifiedinSection2.3.1withthefollowingconstraints:
The‘uvvu’brandSHALLbesetasacompatible_brandintheFileTypeBox(‘ftyp’).Note:signalingofthe‘uvvu’brandindicatesthatthefilefullycomplieswiththerequirementsinthisAnnex. Ifthemajor_brandfieldissetto‘uvvu’,theminor_versionfieldSHALLbesetto
theintegerrepresentationofDMEDIA_VERSION_NOPOINTS(definedinAnnexA.).
E.1.3. Constraints on ‘ccff’ Boxes
E.1.3.1. ContentInformationBox(‘coin’)
DCCsconformingtotheDECEFileFormatshallincludeaContentInformationBox(‘coin’)asspecifiedinSection2.2.2withthefollowingconstraints:
Brand: Aniso_brandfieldSHALLbeincludedwiththevalue“uvvu”. Theversionfieldwhichaccompaniestheaboveiso_brandvalueSHALLbesettothe
integerrepresentationofDMEDIA_VERSION_NOPOINTS(definedinAnnexA.). Asset:
AnamespacefieldSHALLbeincludedwiththevalue“urn:dece”. Theasset_idfieldwhichaccompaniestheabovenamespacefieldSHALLbesettothe
AssetPhysicalIdentifier(APID)oftheDCC,asdefinedinSection5.5.1“AssetIdentifiers”of[DSystem].
E.2. MediaProfiles
TheMediaProfilesdefinedinAnnexB.arenotextendedorconstrainedbythe‘uvvu’brand.
E.3. DeliveryTargets
TheDeliveryTargetsdefinedinAnnexC.applytothe‘uvvu’brandwiththeadditionalrequirementsdefinedinthisSection.
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E.3.1. Multi‐Track Download DeliveryTarget
DCCsconformingtothisDeliveryTargetandthe‘uvvu’brandSHALLcomplywiththerequirementsandconstraintsdefinedinAnnex0(Multi‐TrackDownloadDeliveryTarget)withtheadditionalrequirementsdefinedinthisSection.
E.3.1.1. ConstraintsonFileStructure
DCCsconformingtothisDeliveryTargetandthe‘uvvu’brandSHALLcomplywithalloftherequirementsandconstraintsdefinedinAnnexC.2.2withtheadditionalconstraintsdefinedasfollows:
TheBaseLocationBox(‘bloc’)SHALLbepresentintheDCC.
E.4. InternetMediaTypeTemplateandParameters
TheInternetMediaTypeTemplateandParameterrequirementsdefinedinAnnexD.applyfortheDECEFileFormat.
E.5. FileExtensions
ThefileextensionsdefinedinTableE‐1applyfortheDECEEcosystem.TableE‐1–DECEFileFormatFileExtensionRequirements
DCCType FileExtensionDECEMulti‐TrackDCC .uvuDECEVideoSingle‐TrackDCC .uvvDECEAudioSingle‐TrackDCC .uvaDECESubtitleSingle‐TrackDCC .uvt
E.6. DECEInteroperabilityPoints
TheTablesbelowdefinewhichcombinationsofMediaProfiles,DeliveryTargetsandmandatorycodecsaresupportedbytheDECEEcosystem.Thesecombinationsarecalled“InteroperabilityPoints”.TheseTablesusethefollowingheadings:
“InteroperabilityPoint”–identifiestheInteroperabilityPoint. “MediaProfile”–referstoaMediaProfiledefinedinAnnexB. “DeliveryTarget”–referstoaDeliveryTargetdefinedinAnnexC. “MandatoryVideoCodecs”–defineswhichvideocodecs,withinthelistedMediaProfile,are
mandatedbytheInteroperabilityPoint.ContentthatcomplieswiththeInteroperabilityPointwillhaveatleastonevideotrackavailablewhichisencodedwithamandatoryvideocodec.
“MandatoryAudioCodecs”–defineswhichaudiocodecswithinthelistedMediaProfilearemandatedbytheInteroperabilityPoint.ContentthatcomplieswiththeInteroperabilityPointwillhaveatleastoneaudiotrackavailablewhichisencodedwithamandatoryaudiocodec.
TableE‐2–AVCDownloadandPrepackagedInteroperabilityPointsInteroperabilityPoint Media
ProfileDeliveryTarget MandatoryVideoCodecs MandatoryAudioCodecs
SD‐MDL SD Multi‐TrackDownload AVC MPEG‐4AAC2‐Channel
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HD‐MDL HD Multi‐TrackDownload AVC MPEG‐4AAC2‐ChannelSD‐AVC‐SDL SD Single‐TrackDownload AVC MPEG‐4AAC2‐ChannelHD‐AVC‐SDL HD Single‐TrackDownload AVC MPEG‐4AAC2‐ChannelSD‐AVC‐PP SD Pre‐Packaged AVC MPEG‐4AAC2‐ChannelHD‐AVC‐PP HD Pre‐Packaged AVC MPEG‐4AAC2‐Channel
TableE‐3–AVCStreamingInteroperabilityPointsInteroperabilityPoint Media
ProfileDeliveryTarget MandatoryVideoCodecs MandatoryAudioCodecs
SD‐AVC‐STR SD Streaming AVC MPEG‐4AAC2‐ChannelHD‐AVC‐STR HD Streaming AVC MPEG‐4AAC2‐Channel
TableE‐4–HEVCDownloadandPrepackagedInteroperabilityPointsInteroperabilityPoint Media
ProfileDeliveryTarget MandatoryVideoCodecs MandatoryAudioCodecs
SD‐HEVC‐SDL SD Single‐TrackDownload AVCorHEVC MPEG‐4AAC2‐ChannelHD‐HEVC‐SDL HD Single‐TrackDownload AVCorHEVC MPEG‐4AAC2‐ChannelSD‐HEVC‐PP SD Pre‐Packaged AVCorHEVC MPEG‐4AAC2‐ChannelHD‐HEVC‐PP HD Pre‐Packaged AVCorHEVC MPEG‐4AAC2‐Channel
TableE‐5–HEVCStreamingInteroperabilityPointsInteroperabilityPoint Media
ProfileDeliveryTarget MandatoryVideoCodecs MandatoryAudioCodecs
SD‐HEVC‐STR SD Streaming AVCorHEVC MPEG‐4AAC2‐ChannelHD‐HEVC‐STR HD Streaming AVCorHEVC MPEG‐4AAC2‐Channel
Note:thePD,xHD,UHD,HDR10,DVandHDR12MediaProfilesarenotcurrentlysupportedbytheDECEEcosystemintheformofPhysicalAssets.
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