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1,1,2(1.,100083;2.,100876):,DCT88DCT4488DCT;;,:;;;:TN919.8:A:1005-7641(2006)03-0001-041,,ITU-TISO/IEC:ITU-TH.261H.263H.264,,;MPEGISO/IEC,(DVD),H.262MPEG-2,H.264MPEG-41011Fig.1Evolutionofinternationalstandardsforvideocodec2,,2DCT,2H.264Fig.2GeneralblockdiagramofvideocodecandimprovementofH.264,1,,,;,,,,,127161Vol.27No.1612006310TelecommunicationsforElectricPowerSystemMar.10,2006©1994-2007ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(DCT)(1)DCTDCT,1977,DCT,2090DCTLoefflerLigtenbergMoschytz1989LLM,1129,DCT(2)DCTDCT,2080DCT,44881616,(QCIFCIFSDTVHDTV)DCTH.26444,,(3)DCTDCTDCT,,,,DCT,H.264,H.264,,,,3.2,,,(),,,,;,,,,80%,,(1)(),,,H.261,H.263MPEG-21/2,MPEG-41/2,1/4H.2641/41/8,,1/41/4,,(2),,(),,,(),H.2611616H.26388H.26444,,,,22006,27(161)©1994-2007ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(3),,,,,,,,,(B),,,(4),3,,,,,,4,,,,,(VLC),VLC,,Huff2man,,,Huff2man,,VLC,,VLC,,,,,H.264(CAVLC),(CABAC),,,,,,,53,,(1),,,,H.261,,H.263+MPEG-4,,H.264,,,I,,3©1994-2007ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.(2),,,,,,,,H.261,,[1/4,1/2,1/4]H.264,5,6,,AVSH.264/MPEG-4AVCSMPTEVC1/MSWMV93,MPEG-2H.263MPEG-4,,,H.264VC1,,,,VC-1WMV9,SMPTE,(Z):[1]ITU2TRecommendationH.2612Videocodecforaudiovi2sualservicesatp64kbits2Prepublished[S].1993.[2]ITU2TRECH.2622Genericcodingofmovingpicturesandassociatedaudioinformation[S].1995.[3]ITU2TRecommendationH.2612Videocodingforlowbitratecommunication[S].1996.[4]ITU2TRecommendatioH.2642Advancedvideocodingforgenericaudiovisualservices2prepublished[S].2003.[5]ChenW.H.Afastcomputationalalgorithmforthedis2cretecosinetransform[S]IEEEtransactionsonCommu2nications.[6]C.Loeffler,A.Ligtenberg,G.Moschytz.PracticalFast12DDCTAlgorithmswith11Multiplications.Proc[S].Intl.Conf.onAcoustics,Speech,andSignalProcessing1989.[7],,,.H.264[J].,2004,(3):33-36.[8],.H.264[J].,2002,(11):1-6.[9],,,.[J].,2003,(8):8-11.[10],,.H.264[J].,2003,(7):12-14.(1976-),,,,(1976-),,,,(1966-),,,,EvolutionofkeytechnologiesinmodernvideocodingLIANGFu2yu1,LIJuan1,MENAi2dong2(1.ChinaOrientTelecommSatelliteCompany,Ltd,Beijing100083,China;2.SchoolofTelecomEngineering,BeijingUniversityofPostsandTelecommunications,Beijing100876,China)Abstract:Thehistoryofmodernvideocodingisbrieflyintroducedinthispaper,andtheevolutionofkeytechnologiesinhybridDCTschemesuchasDCTtransform,predictioncodingwithmotioncompensationandentropycodingetc.arediscussedtoo.Conventional88DCTisreplacedbyinteger44or88DCT,theelementofmotioncompensationisimprovedcontinuously,includingtheprecision,figure,sizeandnumberofreferenceframe.Theentropycodingmethodswhichadoptedfixedcodetableandprobabilitymodelareimprovedtoadaptivecontext2basedalterablewordlengthcoding.Theevolutionofthesekeytechnologieshasimprovedtheperformanceofvideocompression.Keywords:videocoding;transformcoding;motionestimation;entropycoding42006,27(161)©1994-2007ChinaAcademicJournalElectronicPublishingHouse.Allrightsreserved.