HDTV到SDTV視頻轉(zhuǎn)碼關(guān)鍵算法的研究與軟件實現(xiàn).pdf

1、電子科技大學(xué)碩士學(xué)位論文HDTV到SDTV視頻轉(zhuǎn)碼關(guān)鍵算法的研究與軟件實現(xiàn)姓名：李延奇申請學(xué)位級別：碩士專業(yè)：信號與信息處理指導(dǎo)教師：朱維樂20060501ABSTRACTABSTRACTCurrently，severalvideocompressionstandardsexistfordifferentmultimediaapplicationsThesestandardsdifferfromeachotherinthecompres

2、sionalgorithmsandsyntaxH261、H262、H263areaimedatlowbit—ratevideoapplicationssuchasvideophoneandvideoconferencingMPEG一2isaimedforhi曲bitratehi曲qualityapplicationssuchasdigitalTVbroadcastingandDVD，andMPEG一4isaimedatmultimedi

3、aapplicationsincludingstreamingvideoapplicationsonmobiledevicesVideotranscodingperformsoneormoreoperations，suchasbitrateandformatconversions，totransformonecompressedvideostreamtoanotherAsthenumberofapplicationsincreasesa

4、ndvariousnetworkssuchaswirelineandwirelessintegratewitheachother，intercompatibilitybetweendifferentsystemsanddifferentplatformsarebecominghi曲lydesirableTranscodingisneededbothwithinandacrossdifferentstandardstoallowthein

5、teroperationofmultimediastreamsThus，videotranscodingisoneoftheessentialcomponentsforcurrentandfuturemultimediasystemsthataimtoprovideuniversalaccessThispaperstudiesthearchitecturesandkeyalgorithmsofthetranscodingfromHDTV

6、toSDTVintheDCTdomainThekeyalgorithmsincludes：motionvectormapping，picturedownsizinginDCTdomain，motioncompensationinDCTdomainandratecontr01Bychoosingtheappropriatearchitechtureandalgorithms，thetranscodingcomplexityisreduce

7、dandthetranscodedvideoqualityismaintainedComparedwiththetraditionalpixeldomaintranscoding，ourtranscodingschemenotonlyavoidstheDCTandIDCToperationsbutalsoavoidscomputation—expensivemotionestimationbyreusingthemotioninform