英语网站导航,周来强,杨婧琳
摘要在无线移动信道和因特网等环境下的压缩视频传输业务,信道传输差错不但严重影响业务质量,甚至会导致整个视频通讯完全失效,因此差错复原技术就成为易发生差错信道下视频编码的重要组成部分.在h.263 ,h.263 和mpeg-4等视频编码标准中均采用了若干差错复原技术或工具.该文对目前各种新的视频编码标准中所应用的一些差错复原技术,如重同步、数据分割、可逆变长编码、参考图象选择、差错掩盖等的内容、原理进行了具体的叙述.并利用第三代移动通讯系统的信道模型进行了差错复原技术的实验.结果表明,在应用了差错复原技术后,重建图象的主客观质量均得到了明显的改善.关键词视频编码差错复原数据分割可逆变长编码差错掩盖errorresilienceinvideocoding
liangfan,weixiao-hui,xiaozi-mei,liuhong-mei
(schoolofinformationscienceandtechnology,zhongshanuniversity,guangzhou510275)
abstracttheproblemoferrorresilienceincompressedvideocommunicationisbecomingincreasinglyimportantbecauseofthegrowinginterestinvideodeliveryovererror-pronechannelssuchasmobilenetworksandtheinternet.oneinherentproblemofsucherror-pronechannelsischannelerrors.currentvideocompressionstandardsachieveefficientcompressionbyusingpredictivecodingandvariablelengthentropycoding.variablelengthcodingschemesarehighlyvulnerabletochannelerrors.predictivecodingmakemattersmuchworsesincetheerrorsquicklypropagateacrosstheentirevideosequence.sotheeffectoftheseerrorsnotonlycancausegreatdegradationofthequalityofservice,evencanleadtothefailureofthewholevideocommunicationsystem.someerrorresiliencetechnologieshavealreadybeenincludedinseveralvideocodinginternationalstandardssuchash.263 ,h.263 andmpeg-4.thisarticlegivesadetaildescriptionofthecontentandprincipleoferrorresiliencetechnologies,suchasresynchronization,datapartitioning,reversiblevariablelengthcoding,referencepictureselectionmodeanderrorconcealment,etc,whichareusedindiversifiednewvideocodinginternationalstandards.thisarticlealsogivessomesimulationresultsoferrorresiliencetechnologiesbasedonimt-2000channelmodels.theresultshowserrorresiliencetechnologiescanremarkablyimprovethesubjectiveandobjectivequalityofthereconstructedimage.keywordsvideocoding,errorresilience,datapartitioning,reversiblevariablelengthcoding,errorconcealment0