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ID:36531316
大小:2.35 MB
页数:75页
时间:2019-05-11
《H.264视频编码标准码率控制算法的优化》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、西南交通大学硕士学位论文H.264视频编码标准码率控制算法的优化姓名:李慧然申请学位级别:硕士专业:计算机应用技术指导教师:彭强20080401AbstractH。264videocodingstandardisprovidedformallybyITU—U/ISO.TheframeworkofH.264issimilarwithallvideoencodingstandards。Andmanynewtechnologies,suchasspatialpredictionintraencoding,adaptiveblocksizemotioncompensation,4x4intege
2、rtransformation,multiplereferencepicturesandcontentadaptivebinaryarithmeticcoding(CABAC),areusedinit.Thesignal/noiserationobviouslyraisedinsamebitrateinthisstandard.Soitobtainsmuchattentionfromacademicandindustrialfields.Andtherearedifficultiesofencodingbecauseofthenewtechnology.Forexample.rateco
3、ntrolofH.264becomesdifficultbecauseofthechickenandeggdilemmawhichbroughtbythequantizationparameterusedforratedistortionwhichdeterminesthebestcodingmodeandtheratecontr01.SothenewratecontrolalgorithmsaredesignedtOdealwiththisproblem.AndtherearedefaultsofnewalgorithmsforH.264ratecontrolfacedtothemov
4、ef.astsequences,suchasaverageallocatingbitrateandinaccurateMADprediction.SothisdissertationproposesanimprovedratecontrolalgorithmforH.264basedonthedetectionofsciencechangeandmovement.ThecomputingofratecontrolmodelexploitedbyH.264iscomplex.Andtheimpreciseratecontrolisbroughtbyit.Thereforeanonzeroc
5、oefficientbasedonamapISproposedtodealwiththesedefaults..Firstlyanimprovedratecontrolalgorithmisproposedbasedonthedetectionscenechangeandhighmotion.TheimprovedratecontrolalgorithmoptimizeslinearMADpredictionmodelinencodingprocesswhenthescenechangeorhighmotionpicturesaredetected.Andthen,thisoptimiz
6、edMADwillbeusedtocomputinganoptimizedquantization.AndbitrateallocatingISaccordingtothecomparabilityofframesinasamecomplication·Lastlv.anoI屹eroratecontrolbasedonamapisdiscussed.Therelationshipbetweennonzeroandbitrateisstudiedtooptimizeratetocontrolbitrate,combinedwithaquantizationandraterelationsh
7、ipmap.ThesimulationshowsthatthePSNRofimprovedratecontrolalgorithmbasemotiondetectionisobviouslyimprovedforthepictureswithhighmotionbycomparedtoJVT.G012.AndthePSNRofnonzeroratecontrolbasedonamapiSobviouslyincreasedwhent
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