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Review on: Blu-ray Disc

BY:

K.SirishaSanth Samarth Engineering

[email protected]

Abstract

The modern world of technology could not have

come about excet for the develoment of the

comuter. !any eole believe that storage is the

most imortant feature in a "C. #or these reasons

comuter storage systems have grown in caacityand seed at about the same rate as rocessors.

Today$ otical systems are the most oular

alternatives to magnetic storage systems. The

most widely used otical systems are C%s and

%&%s.

'ecause of the continuing demand for greater

storage caacity$ hardware manufacturers are

always searching for alternative storage media.

This led to the introduction of 'lu(ray %isc)'%*. The aim of this aer is to study theadvantages of the 'lu(ray %isc over the %&%s

and other otical systems.+ith their high storage caacity$ 'lu(ray discs

can hold and lay bac, large -uantities of high(

definition video and audio$ as well as hotos$ data

and other digital content.

n this aer$ a detailed comarison is made

between 'lu(ray %isc and %&%s based on theirwor,ing$ writing$ caacity$ comatibility and

other arameters.

Introduction

In 1997, a new technology emerged that broughtdigital sound and video into homes all over theworld. It was called%&%, and it revolutionized themovie industry. The industry is set for yet anotherrevolution with the introduction of lu!ray "iscs

#"$.. The format offers more than five times the

storage ca%acity of traditional "&"s and can hold

K.S%andanaSanth Samarth EngineeringCollege

Sandana_/[email protected]

u% to '() on a single!layer disc and (*) on adual!layer disc.

The name lu!ray is derived from theunderlying technology, which utilizes a blue!violetlaser to read and write data.

The lu!ray "isc format was develo%ed by thelu!ray "isc +ssociation #"+$, a grou% ofleading consumer electronics, %ersonal com%uterand media manufacturers, with more than 1*member com%anies from all over the world. The

oard of "irectors currently consists of+%%le -om%uter, Inc."ell Inc.itachi /td/) 0lectronics Inc.,Samsung 0lectronics /tdSony -o /td etc. + current, single!sided, standard "&" can hold.7 ) #gigabytes$ of information. That2s aboutthe size of an average two!hour, standard!definition movie with a few e3tra features. ut ahigh!definition movie, which has a much clearerimage, ta4es u% about five times more bandwidthand therefore re5uires a disc with about five timesmore storage. +s T& sets and movie studios ma4ethe move to high definition, consumers are goingto need %laybac4 systems with a lot more storageca%acity.

lu!ray is the ne3t!generation digital videodisc. It can record, store and %lay bac4 high!definition video and digital audio, as well ascom%uter data. The advantage to lu!ray is thesheer amount of information it can hold6
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+ single!layer lu!ray disc, which is roughlythe same size as a "&", can hold u% to '7 ) ofdata !! that2s more than two hours of high!definition video or about 1 hours of standardvideo.

+ double!layer lu!ray disc can store u% to (*

), enough to hold about .( hours of high!definition video or more than '* hours of standardvideo. +nd there are even %lans in the wor4s todevelo% a disc with twice that amount of storage.

BD Formats

+s with conventional -"s and "&"s, lu!ray

%lans to %rovide a wide range of formats including8:;8;8sers will

be able to connect to theInternet and instantlydownload subtitles and

other interactive moviefeatures.

"iscs store digitally encoded video and audioinformation in %its !! s%iral grooves that run fromthe center of the disc to its edges. + laser reads theother side of these %its !! the bum%s !! to %lay themovie or %rogram that is stored on the "&". Themore data that is contained on a disc, the smallerand more closely %ac4ed the %its must be. The

smaller the %its #and therefore the bum%s$, themore %recise the reading laser must be. >nli4ecurrent "&"s, which use a red laser to read andwrite data, lu!ray uses a blue laser #which iswhere the format gets its name$. + blue laser has ashorter wavelength #*( nanometers$ than a red

laser #?(* nanometers$. The smaller beam focusesmore %recisely, enabling it to read informationrecorded in %its that are only *.1( microns #@m$ #1micron A 1*!? meters$ long !! this is more thantwice as small as the %its on a "&". =lus, lu!rayhas reduced the trac4 %itch from *.7 microns to*.' microns. The smaller %its, smaller beam andshorter trac4 %itches together enable a single!layerlu!ray disc to hold more than '( ) ofinformation !! about five times the amount ofinformation that can be stored on a "&".

0ach lu!ray disc is about the same thic4ness #1.'millimeters$ as a "&". ut the two ty%es of discsstore data differently. In a "&", the data is

sandwiched between two %olycarbonate layers,each *.?!mm thic4. aving a %olycarbonate layeron to% of the data can cause a %roblem called

birefringence, in which the substrate layer refractsthe laser light into two se%arate beams. If the beamis s%lit too widely, the disc cannot be read. +lso, ifthe "&" surface is not e3actly flat, and istherefore not e3actly %er%endicular to the beam, itcan lead to a %roblem 4nown as disc tilt, in whichthe laser beam is distorted. +ll of these issues leadto a very involved manufacturing %rocess.The lu!ray disc overcomes "&"!readingissues by %lacing the data on to% of a 1.1!mm!

thic4 %olycarbonate layer. aving the data on to%%revents birefringence and therefore %reventsreadability %roblems. +nd, with the recordinglayer sitting closer to the obBective lens of thereading mechanism, the %roblem of disc tilt isvirtually eliminated. ecause the data is closer tothe surface, a hard coating is %laced on the outsideof the disc to %rotect it from scratches andfinger%rints.


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a!acity

+ single!layer disc can hold '() and a dual!layer disc can hold (*) data and over 9 hours ofhigh!definition #"$ video on a (*) disc andabout ' hours of standard!definition #S"$ videoon a (*) disc can be fit. To ensure that the lu!ray "isc format is easilye3tendable #future!%roof$ it also includes su%%ort

for multi!layer discs, which should allow thestorage ca%acity to be increased to 1**)!'**)#'() %er layer$ in the future sim%ly by addingmore layers to the discs. Sony has announced thatlayering a disc beyond dual layering is %ossible,allowing u% to a '**) ca%acity on a lu!8aydisc with layers.

om!atibility

ac4wards com%atibility with "&" was one ofthe %rimary arguments " "&" had against lu!8ay, but as recent develo%ments have suggested,that doesn2t really a%%ly anymore. In fact, Bust this

%ast wee4, we re%orted on the C";-" "ualDormat "isc,C which is a disc containing both lu!8ay and -" data layers.

"!eed

lu!ray has a higher data transfer rate !! ? :b%s#megabits %er second$ !! than today2s "&"s,

which transfer at 1* :b%s. + lu!ray disc canrecord '( ) of material in Bust over an hour and

a half. lu!ray also has the %otential for much

higher s%eeds, as a result of the larger numericala%erture #E+$ ado%ted by lu!ray "isc. The largeE+ value effectively means that lu!ray willre5uire less recording %ower and lower discrotation s%eed than "&" and "!"&" to achievethe same data transfer rate.


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recording layer remain the same. +s %roductionvolumes increase the %roduction costs should falland eventually be com%arable to "&"s.

%eed to u!grade

The %roblem with today2s "&"s is that they onlysu%%ort S" and don2t have the necessary storageca%acity to satisfy the needs of ". That2s wherelu!ray comes in, it offers u% to (*) of storageca%acity and enables %laybac4, recording andrewriting of " in all of the " resolutionsincluding 1**%. The format also su%%orts high!definition audio formats and lossless audio.

In addition to the greater video and audio5uality, the e3tra storage ca%acity also means therewill be %lenty of room for additional content ands%ecial features. This combined with the new "!Finteractivity layer ado%ted by lu!ray will bringthe menus, gra%hics and s%ecial features to awhole new level.

Di$$erences between Blu-ray and DVD

&arameters

Blu-ray DVD

Storage ca%acity '()#single!layer$(*) #dual!layer$

.7)#single!layer$.()#dual!layer$

/aser wavelength *(nm #bluelaser$

?(*nm #redlaser$

Eumericala%erture #E+$

*.( *.?*

"isc diameter"isc thic4ness

1'*mm1.'mm

1'*mm1.'mm

=rotection layerard coating

*.1mmGes

*.?mmEo

Trac4 %itch *.'H@m *.7H@m"ata transfer rate#data$"ata transfer rate#video;audio$

?.*:b%s#13$(.*:b%s#1.(3$

11.*:b%s#13$1*.*:b%s#13$

Blu-ray Vs 'D-DVD

The other big %layer is "!"&", also calledA(D #+dvanced %tical "isc$, which wasdevelo%ed by electronics giants Toshiba and E0-."!"&" was actually in the wor4s before regular"&", but it didn2t begin real develo%ment until'**.

+lthough lu!ray and "!"&" are similar inmany as%ects, still they differ in6 a!acity: lu!ray utilizes a lens with agreater numerical a%erture #E+$ than "!"&",the laser s%ot can be focused with greater %recisionto fit more data on the same size disc. This allowslu!ray to hold '() %er layer #(*) on a dual!layer disc$, whereas "!"&" can only hold1() %er layer #*) on a dual!layer disc$. lu!ray has also ado%ted a higher data transfer rate forvideo and audio #(:b%s vs ?.((:b%s$. Thegreater ca%acity and data transfer rates for lu!raywill allow the movie studios to release theirmovies with higher 5uality video and audio thanthe "!"&" format.

ontent: The lu!ray format has receivedbroad su%%ort from the maBor movie studios as asuccessor to today2s "&" format. Seven of theeight maBor movie studios #


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laser$ laser$Eumericala%erture #E+$

*.( *.?(

"isc diameter"isc thic4ness

1'*mm1.'mm

1'*mm1.'mm

=rotection layer

ard coating

*.1mm

Ges

*.?mm

EoTrac4 %itch *.'H@m *.*H@m"ata transfer rate#data$"ata transfer rate#video;audio$

?.*:b%s#13$(.*:b%s#1.(3$

?.((:b%s#13$?.((:b%s#13$

(t#er com!etitors

lu!ray and "!"&" are the two maBorcom%etitors in the mar4et, but there are othercontenders, as well.


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to invest in a new %layer. The industry is %lanningto mar4et bac4ward!com%atible drives with both

blue and red lasers, which will be able to %laytraditional "&"s and -"s as well as lu!raydiscs.

Blu-ray advantages

record high!definition television #"T&$without any 5uality loss

instantly s4i% to any s%ot on the disc record one %rogram while watching

another on the disc create %laylists edit or reorder %rograms recorded on the

disc

automatically search for an em%ty s%aceon the disc to avoid recording over a

%rogram access the %grade costs might be %assed ontoconsumers.

"u!!orts mandatory managed co!y

:andatory managed co%y #::-$ will be %art ofthe lu!ray format. This feature will enableconsumers to ma4e legal co%ies of their lu!raymovies that can be transferred over a home

networ4. =lease note that CmandatoryC refers to themovies having to offer this ca%ability, while it willbe u% to each hardware manufacturer to decide ifthey want to su%%ort this feature.

A!!lications

om!atibility6


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=-s with "!8:,"!8TIE in "igital storage "iscs.

Re$erences

P1Q. =eter Eorton, RIntroduction to com%uters,Tata :c)raw!ill %ublishers

'. www.howstuffwor4s.com. www.techcraze.net. www.wi4i%edia.org(. www.blu!ray.com?. www.blu!raydisc.com7. www.sony.com

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