cea-861 plug fest #9 tech session oct 31, 20071 testing hdmi lipsync mark stockfisch vice president...
TRANSCRIPT
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Testing HDMI Lipsync
Mark Stockfisch
Vice President & CTO Quantum Data
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Overview
• Lipsync problem (example)• HDMI’s lipsync solution• Lipsync test tools• How to use these tools to measure lipsync
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Good Lipsync
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Bad Lipsync - Audio Leads
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Bad Lipsync - Video Leads
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What is HDMI lipsync?• HDMI sinks and repeaters can now declare
audio/video latency information in their EDIDs
• Lipsync-aware sources may delay audio or video to compensate for latencies in downstream devices
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Example Without HDMI Lipsync
Audio
Video
42ms
Repeater (AVR)
0ms
Video
Audio
Video
Source (STB)
0ms Repeater is unaware of 42ms video processing
delay in the DTV...
... so audio leads 42 .video by ms
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Same Example With HDMI Lipsync
Video
Audio
Video
Source (STB)
0ms
EDID
Latency Data
Audio
Video
Repeater (AVR)
0ms
Delay
42ms0ms
42ms
...so audio & video are now in sync.
Repeater is aware of and compensates for video
processing delay in the DTV...
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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New Lipsync Tools
• New data fields in EDID Editor• New Signal Generator/Analyzer Features• Lipsync Adapter (converts aural chirp, flash of light, non-HDMI
analog/digital audio signals to simple digital pulses)• Lipsync Calibrator (calibrated sound & light source for doing
“sanity checks”)
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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EDID Editor - HDMI VSDB Lipsync Data
Audio processing delay0-500ms or INVALID
Video processing delay0-500ms or INVALID
Maybe 2nd value for interlace
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Generator’s New Test Image “LipsyncB”
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“LipsyncB” Test Image Specification
• Flashing full-white square 1/8th of major active axis
• Only appears in first field of interlaced formats
• Audio burst (2 to 3 cycles of sine wave @1kHz) positioned relative to center of flashing square plus or minus 500 ms
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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“LipsyncB” Test Image Controls
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Analyzer’s Lipsync Meter - Relative Mode
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Instrument (882EA emulating a STB)
Measure Sink’s Latencies
LipsyncAdapter
Sink (DTV or AVR)
Audio/Video (TMDS)
Optical Sensor
Audio/VideoDigital Pulses
“LipsyncB”
Test Image
Microphone or Analog/Digital Signal
2 - Lipsync adapter converts visual flash and (or) audible chirp into digital pulses
1 - Instrument outputs “LipsyncB” test image with latency set to zero
3 - Instrument measures delay between generator’s flash/chirp event and incoming pulses - then indicates sink’s audio and (or) video latencies
42ms
HDMI Cable
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Instrument (882EA emulating a STB)
Functionally Test Sink’s EDID Lipsync Data
LipsyncAdapter
Sink (DTV or AVR)
Audio/Video (TMDS)
Optical Sensor
Audio/VideoDigital Pulses
“LipsyncB”
Test Image
EDID (DDC)0101010101010101010101010101010101010101010101010101
Microphone or Analog/Digital Signal
1 - Instrument reads latency data from the sink’s EDID
3 - Lipsync adapter converts visual flash & audible chirp into digital pulses
2 - Instrument outputs “LipsyncB” test image with latency-compensated audio/video
4 - Instrument measures delay between pulses and indicates latency error
0ms
HDMI Cable
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Instrument (882EA emulating a DTV)
Functionally Test Source’s Lipsync Comp
Audio/Video (TMDS)Source (DVD)
2 - Instrument generates hot-plug and source reads latency data from instrument’s EDID emulator 1 - Instrument’s EDID emulator
presents audio/video latency test value to the source (+42ms)
3 - Source outputs test image (e.g. “LipsyncB” image from test DVD) with the requested audio/video latency compensation
4 - Instrument measures incoming audio/video lipsync, which should compensate the value presented in the EDID (-42ms)
01010101010101010101010101010101010101010101010 -42ms
HDMI Cable
EDID (DDC)
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Instrument (882CA)
Functionally Test Repeater’s Lipsync Comp
5 - Instrument measures delay between audio & video and indicates any latency error
2 - Repeater incorporates instrument’s latency data in its EDID
4 - Instrument outputs “LipsyncB” test image with corrected audio/video and repeater passes it back to the instrument
Au
dio
/Vid
eo (T
MD
S)
0101010101010101010101010101 - Instrument generates hot-plug and repeater’s source reads latency data from instrument’s EDID emulator
ED
ID (D
DC
)
ED
ID (D
DC
)
010101010101010101010101010
Repeater’sSource
Repeater’sSink
Instrument’sSink(emulating a DTV)
Instrument’sSource(emulating a STB)
Au
dio
/Vid
eo (T
MD
S)
Instrument’s Sink(emulating a DTV)EDID
Repeater’s SinkEDID
0ms
3 - Repeater generates hot-plug and the instrument’s source reads latency data from repeater’s EDID
Repeater
CEA-861 Plug Fest #9Tech Session Oct 31, 2007
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Summary
• Lipsync problems happen• HDMI has new features that allow source devices to
compensate for unmatched signal paths - when sink and repeater devices provide EDID latency data
• New tools now exist for testing these features
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Questions?