简介:ThisletterproposesaratecontrolalgorithmforH.264videoencoder,whichisbasedonblockactivityandbufferstate.ExperimentalresultsindicatethatithasanexcellentperformancebyprovidingmuchaccuratebitrateandbettercodingefficiencycomparedwithH.264.ThecomputationalcomplexityofthealgorithmisreducedbyadoptinganovelblockactivitydescriptionmethodusingtheSumofAbsoluteDifference(SAD)of16×16mode,anditsrobustnessisenhancedbyintroducingafeedbackcircuitatframelayer.
简介:ThenewH.264videocodingstandardachievessignificantlyhighercompressionperformancethanMPEG-2.AstheMPEG-2ispopularindigitalTV,DVD,etc.,bandwidthormemoryspacecanbesavedbytranscodingthosestreamsintoH.264intheseapplications.Unfortunately,thehugecomplexitykeepstranscodingfrombeingwidelyusedinpracticalapplications.Thispaperproposesanefficienttranscodingarchitecturewithasmartdownscalingdecoderandafastmodedecisionalgorithm.Usingtheproposedarchitecture,hugebufferingmemoryspaceissavedandthetranscodingcomplexityisreduced.Performanceoftheproposedfastmodedecisionalgorithmisvalidatedbyexperiments.
简介:Inthispaper,afuzzyreasoningbasedtemporalerrorconcealmentmethodisproposed.ThebasictemporalerrorconcealmentisimplementedbyestimatingMotionVector(MV)ofthelostMacroBlock(MB)fromitsneighboringMVs.WhichMVisthemostproperoneisevaluatedbysomecriteria.Generally,twocriteriaarewidelyused,namelySideMatchDistortion(SMD)andSumofAbsoluteDifference(SAD)ofcorrespondingMV.However,eachcriterioncouldonlypartlydescribethestatusoflostblock.Toaccomplishthejudgementmoreaccurately,thetwomeasuresareconsideredtogether.ThusarefinedmeasurebasedonfuzzyreasoningisadoptedtobalancetheeffectsofSMDandSAD.TermsSMDandSADareregardedasfuzzyinputandtheterm‘similarity’asoutputtocompletefuzzyreasoning.ResultoffuzzyreasoningrepresentshowthetestedMVissimilartotheoriginalone.Andk-meansclusteringtechniqueisperformedtodefinethemembershipfunctionofinputfuzzysetsadaptively.Accordingtotheexperimentalresults,theconcealmentbasedonnewmeasureachievesbetterperformance.
简介:详细阐述了针对ADSP—BF561双核DSP芯片的H.264视频编码算法进行优化的具体方法。试验数据表明,优化后的编码器性能得到了全面提升。可以实现基于ADSP—BF561双核平台上的4CIF视频实时编码。
简介:图像压缩技术是基于在空域,时域或者频域上移除数据冗余的算法。它相当大地减少了数据转换率,但是随之的视频压缩信号对于传输误差更加敏感。差错恢复技术相对于通道误差增强了视频比特流的鲁棒性。在H.264/AVC的条带编码作为一种差错恢复技术之一被用于限制接收视频品质的数据丢失效应。有一种模式非常重要,它是将图像的宏块分配成不同的条带组,并能够提供不同的差错恢复标准。该文将深入分析这一类分散类型的灵活的宏块顺序(FMO)模式性能,并提出一个定义明确的系统模式,可以更完全地挖掘宏块顺序中离差概念从而克服误差损失。仿真结果显示:新的改进方案的性能优于传统模式。