Video-Payload-H264-09Aug2011-errata原版完整文件

ErrataforUSBVideoPayloadH2641.0

Erratafor“USBVideoPayloadH2641.0”asofAugust9,2011.Checkthe

websiteforthelatesterrata.

1.ErratawLayerID

SectionofSpecification“USBVideoPayloadH2641.0”

Section2.21ofFAQ““USBVideoPayloadH264FAQ1.0”

Background:ThewLayerIDstructureparametersbitsarenotconsistentwiththeH.264specification.

Change:

wLayerID

Reserved

(3bits)

StreamID

(3bits)

QualityID

(3bits)

DependencyID

(4bits)

TemporalID

(3bits)

15 13

12 10

9 7

6 3

2 0

Table3:wLayerIDStructure

Changeto:

wLayerIDforSVCStreams

Reserved

(3bits)

StreamID

(3bits)

TemporalID

(3bits)

QualityID

(4bits)

DependencyID

(3bits)

15 13

12 10

9 7

6 3

2 0

wLayerIDforMVCStreams

Reserved(3bits)

StreamID(3bits)

TemporalID(3bits)

ViewID(7bits)

15 13

12 10

9 7

6 0

Table3:wLayerIDStructure

StreamID:

TheStreamIDprovidesspecificationofaspecificH.264streaminthecaseofasimulcastsequence.TheStreamIDhas3bits(bits12-10inwLayerID)tosupport7streams(0-6).Avalueof7shallbeusedtosimultaneouslyrefertoallstreams.InthecaseofasingleH.264stream,stream_idisalways0.Non-zeroStreamIDonlyappearsincasesofsimulcastoftwoormoreH.264streams.

TemporalID:

TheTemporalIDprovidesspecificationofaspecificTemporalLayerinamulti-layerSVC/MVCstream.TheTemporalIDhas3bits(bits9-7inwLayerID)tosupport7temporallayers(0enhancements–6enhancementslayers).Avalueof7shallbeusedtosimultaneouslyrefertoalltemporallayers.Inthecaseofasingle-layerH.264stream,TemporalIDshallalwaysbe0.InthecaseofaSVCstreamnotusingtemporalscalability,TemporalIDshallalwaysbe0.Anon-zeroTemporalIDshallonlyappearinSVCstreamsusingtemporalscalabilitywhere1indicatesthefirsttemporalenhancementlayer,uptothemaximumtemporalEnhancementlayerbTemporalScaleModesetintheUVCX_TEMPORAL_SCALE_MODEcontrol.

QualityID:

TheQualityIDprovidesspecificationofaspecificQualitylayerinamulti-layerSVCstream.TheQualityIDhas4bits(bits6-3inwLayerID)tosupport15Qualitylayers(0enhancements–14enhancementslayers).Avalueof15shallbeusedtosimultaneouslyrefertoallqualitylayers.Inthecaseofasingle-layerH.264stream,QualityIDshallalwaysbe0.InthecaseofaSVCstreamnotusingMGSmodeSNRscalability,QualityIDshallalwaysbe0.Anon-zeroQualityIDshallonlyappearinSVCstreamsusingMGSmodeSNRscalabilitywhere1indicatesthefirstqualityenhancementlayer,uptothemaximumqualityEnhancementlayer.TheMSGmodeofSNRscalabilitypartitionstransformcoefficientsintoseparateQualitylayers.

DependencyID:

TheDependencyIDprovidesspecificationofaspecificDependencyLayerinamulti-layerSVCstream.TheDependencyIDhas3bits(bits2-0inwLayerID)tosupport7dependencylayers(0enhancements–6enhancementslayers).Avalueof7shallbeusedtosimultaneouslyrefertoallDependencylayers.Inthecaseofasingle-layerH.264stream,DependencyIDshallalwaysbe0.InthecaseofaSVCstreamnotusingeitherCGSmodeSNRscalabilityorSpatialscalabilitymode,DependencyIDshallalwaysbe

0.Anon-zeroDependencyIDshallonlyappearinSVCstreamsusingeitherCGSmodeSNRscalabilityorSpatialscalabilitywhere1indicatesthefirstSNRorspatialenhancementlayer,uptothemaximumSNRorspatialEnhancementlayerdefinedasthesumofbSpatialScaleModeandthenumberofCGSmodeSNRscalableenhancementlayersidentifiedintable8.

ViewID:

TheViewIDprovidesspecificationofaspecificviewinaMVCstream.TheViewIDhas7bits(bits6-0inwLayerID)tosupport62views(0views–62views).Avalueof63shallbeusedtosimultaneouslyreferallviews.Values64to127arereserved.

Reserved:

TheReservedfieldhas3bits(bits15-13inwLayerID)andshallalwaysbe0.

2. ErrataAppendixC“USBVideoPayloadH2641.0”

Section6.1.1CorrelatingbetweenDeviceandPCclocks

Background:Theclarificationontheclockexposed.

Changedto:

Sincethecapturetimeofthevideoframe(PTS)isindicatedbythedeviceusingtheSTC,andA/VsyncwillrelyonPCclockvalue,weneedtocorrelatethetwoclocks.OnWindows,thePCclockexposedviatheQueryPerformanceCounter(QPC).Thecorrelation‘constant’betweenPTSandQPCcanbecalculatedasthemostrecentTotalVideoDelay.

ClockCorrelationConstant(CCC)=TotalVideoDelay Equation4

Section6.1.2VideoTimeStampingBackground:Equation5correction.Changedto:

Thetimestampappliedbythevideodrivertothecurrentvideoframeiscalculatedasthetimestampforthecurrentframe–CCC.

Timest