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1、HEVC核心编码技术讲解(英文讲解有翻译)HEVC核心编码技术之一.图像的编码划分 IV.HEVC的编码技术HEVCVideoCodingTechniquesAsinallpriorITU-TandISO/IECJTC1videocodingstandardssinceH.261[2], theHEVCdesignfollowstheclassicblock-basedhybridvideocodingapproach (asdepictedinFig.1).Thebasicsource-codingalgorithmisahybridofinterpic
2、turepredictiontoexploittemporalstatisticaldependences,intrapicturepredictiontoexploitspatialstatisticaldependences,andtransform codingofthepredictionresidualsignalstofurtherexploitspatialstatistical dependences.ThereisnosinglecodingelementintheHEVCdesignthatprovidesthemajorityofit
3、ssignificantimprovementincompressionefficiencyinrelation topriorvideocodingstandards.Itis,rather,apluralityofsmallerimprovements thatadduptothesignificantgain.和从H.261以来的视频编码标准一样,HEVC的设计沿用了经典的基于块的混合视频编码方式(如图1所示)。基本的信源编码算法是对时域统计相关性使用帧间预测,对空域统计相关性使用帧内预测,再对预测残差信号使得变换编码进一步去除空间统计相关性。HEV
4、C取得比以前的标准更好的压缩效果,而且以很小的改善就取得了很大的收获。Fig.1.TypicalHEVCvideoencoder(withdecodermodelingelementsshadedinlightgray).A.图像的像素表示 SampledRepresentationofPicturesForrepresentingcolorvideosignals,HEVCtypicallyusesatristimulusYCbCrcolor spacewith4:2:0sampling(althoughextensiontoothersamplingf
5、ormatsis straightforward,andisplannedtobedefinedinasubsequentversion).Thisseparates acolorrepresentationintothreecomponentscalledY,Cb,andCr.TheYcomponentis alsocalledluma,andrepresentsbrightness.ThetwochromacomponentsCbandCrrepresenttheextenttowhichthecolordeviatesfromgraytowardbl
6、ueandred,respectively. Becausethehumanvisualsystemismoresensitivetolumathanchroma,the4:2:0sampling structureistypicallyused,inwhicheachchromacomponenthasonefourthofthenumber ofsamplesofthelumacomponent(halfthenumberofsamplesinboththehorizontal andverticaldimensions).Eachsamplefore
7、achcomponentistypicallyrepresentedwith8 or10bofprecision,andthe8-bcaseisthemoretypicalone.Intheremainderof thispaper,wefocusourattentiononthetypicaluse:YCbCrcomponentswith4:2:0samplingand8bpersamplefortherepresentationoftheencodedinputanddecoded outputvideosignal.为了表示色彩视频信号,HEVC使用
8、了典型的三色色彩空间YCbCr,以及4:2:0像素样本。Y表示亮度