H.264+slides.ppt

,2004.10.20.,OverviewofH.264/MPEG-4Part10,Soon-kakKwon,A.Tamhankar,K.R.RaoDongeuiUniversity,T-Mobile,UniversityofTexasatArlington,Contents,IntroductionLayeredStructureVideoCodingAlgorithmErrorResilienceComparisonofCodingEfficiencyConclusions,Introduction,ScopeofImageandVideoCodingStandardsOnlytheSyntaxandDecoderarestandardized:OptimizationbeyondtheobviousComplexityreductionforimplementationProvidesnoguaranteesofquality,Pre-Processing,Encoding,Post-ProcessingKB=0.0722;KR+KB+KG=1Y=0.2126R+0.7152G+0.0722BCb=0.5389(BY);Cr=0.7874(RY)(ITU-RRec.BT.601definesKB=0.114,KR=0.299),RoundingerrorinRGBYCbCr,FRExtOnly:YCgCoCg=GreenChroma;Co=OrangeChromaTofurtheravoidanyroundingerror,addonlyonebitofprecisiontochromasamples,In4:4:4video,FRExthasresidualcolortransform.KeepRGBdomain(samedepth)forinput,outputandstoredreferencepicturesandusetheforwardandinversecolortransformationsinsidetheencoderanddecoderforprocessingoftheresidualdataonly.Eliminatescolor-spaceconversionerrorwithoutsignificantlyincreasingtheoverallcomplexityofthesystem.,Co=(R-B)t=B+(Co1)Cg=GtY=t+(Cg1)Wheretisanintermediatetemporaryvariableand“”denotesanarithmeticrightshiftoperation.Inversecolorspaceconversiont=Y(Cg1)G+t+CgB=t(Co1)R=B+Co,Forwardcolorspaceconversion,Auxiliarypictures,whichareextramonochromepicturessentalongwiththemainvideostream,andcanbeusedforsuchpurposesasalphablendcompositing(specifiedasadifferentcategoryofdatathanSEI).FilmgraincharacteristicsSEI,whichallowamodeloffilmgrainstatisticstobesentalongwiththevideodata,enablingananalysis-synthesisstyleofvideoenhancementwhereinasynthesizedfilmgrainisgeneratedasapost-processwhendecoding,ratherthanburdeningtheencoderwiththerepresentationofexactfilmgrainduringtheencodingprocess.,SEI:SupplementalEnhancementInformation,DeblockingfilterdisplaypreferenceSEI,whichallowstheencodertoindicatecasesinwhichthepicturespriortotheapplicationofthedeblockingfilterprocessmaybeperceptuallysuperiortothefilteredpictures.StereovideoSEIindicators,whichallowtheencodertoidentifytheuseofthevideoonstereoscopicdisplays,withproperidentificationofwhichpicturesareintendedforviewingbyeacheye.,HigherprofilesupportsallcapabilitiesoftheloweronesAlsocapableofdecodingallbitstreamsencodedforthelowernestedprofilesAllhighprofilessupportallfeaturesofthemainprofile,NewProfilesintheH.264/AVCFRExtAmendment,LevelsinH.264/AVC,Level1baddedinFRExt.Forsome3Gwirelessenvironments,LevelsinH.264/AVC,Ifapicturesizeissmallerthanthetypicalpicturesizethenframeratecanbehigheruptoamaximumof172frames/secHorizontalandverticalmaximumsizescannotbemorethansqrt(Total#ofpixels/frame)x8Ifatagivenlevel,picturesizeislessthanthatinthetable,#ofreferenceframesforMEandMCcanbeupto16.,Tomeetmoredemandinghighfidelityapplications,CompressedBitRateMultipliersforFRExtProfiles,Multipliersforfourthcolumnoftableinpage125,24Frames/secfilm1920 x1080progressiveTheHighprofileofFRExtproducednominallybettervideoqualitythanMPEG-2whenusingonlyonethirdasmanybits(8Mbpsversus24Mbps)TheHighprofileofFRExtproducednominallytransparent(i.e.,difficulttodistinguishfromtheoriginalvideowithoutcompression)videoqualityatonly16Mbps.,9T.Wedi,Y.Kashiwagi,“SubjectivequalityevaluationofH.264/AVCFRExtforHDmoviecontent”,JVTdocumentJVT-L033,July2004.,Courtesy:AdvancedTechnologyGroupofMotorolaBCS,Courtesy:AdvancedTechnologyGroupofMotorolaBCS,Fig.7:(a)(e)ComparisonofR-DcurvesforMPEG-2(MP2),MPEG-4ASP(MP4ASP)andH.264/AVC(MP4AVC).Iframeswereinsertedevery15frames(N=15)andtwonon-referenceBframesperreferenceIorPframewereused(M=3).,Courtesy:AdvancedTechnologyGroupofMotorolaBCS,MP4ASPyields1.5codinggainoverMPEG-2.MPEG-4AVCyields2.0codinggainoverMPEG-2.,Highprofileat8MbpsnominallybeatMPEG-2at24MbpsNominallytransparentvideoqualityon1080p24at16Mbps,(FastVDO)Sub-optimalusesofBframesandotheraspectsmaketheplottedperformanceconservativeforFRExt,thustheremarkinthefigureaboutpotentialfutureperformance,HighProfileDetails:DeblockingFilter,CABAC,Signaling,DeblockingFilter:Onlycontroloffilterisadjusted:donotfilter4x4blocksNochangetofilteroperationitselfCABAC:61newcontextsandcorrespondinginitializationvaluesNochangetoCABACengineSignaling:8x8transformon/offflagatPPSlevel8x8transformon/offflagpermacroblockallowsadaptiveuse,Highvs.MainProfileSummary,HighProfilecontains:MainprofileAdaptiveMBlevelswitchingbetween8x8and4x4transformblocksizes.EncoderspecifiedperceptualbasedquantizationscalingmatricesEncoderspecifiedseparatecontrolofeachchromacomponentQPCodingefficiencyimpact(measuredasaveragebit-ratereduction):HDFilm:12%HDVideo(progressive):12%HDVideo(interlace):4%(only2testclips)SDVideo(interlace):6%Complexityimpact:ImplementationbeyondMainProfileaffectsIntraprediction,transform,deblockingfiltercontrol,CABACdecodingNoincreaseincomputationalrequirementsSlightincreaseinmemoryrequirements(CABAC,transform),LicensingofH.264/AVCTechnology,TwopatentpoolstoobtainthelicenseMPEGLAVThesetwopatentpoolsdonotguaranteethattheycovertheentiretechnologyofH.264asparticipationofapatentownerinapatentpoolisvoluntary.,AUDIOcoding&systems,H.264islimitedtovideoAudiocoder:Bi