Study Of Fast Video Transcoding Algorithm Under Multi Video Format

With the development of the broadcasting and IP network transmissiontechnology, the demands and applications for network high definitionvideos grow gradually. Video compression technology also makes steadyprogress accompanied with it. From MPEG-2coding format rised at theend of the last century, to advanced video coding standard H.264whichhas gained nearly a decade of popularity, and then the next generation ofhigh efficiency video coding standard HEVC released early this year, thecompression performance improves continuously. As an important way toenable gradual migration from old standard to the new one, videotranscoding technology has been greatly valued.Traditional transcoding technology could not take both efficiency andvideo quality into account, especially in the case of a high subjectiveoutput video quality, transcoding speed always can not meet userrequirements. Aiming at these problems, we made a deep resreach ontranscoding between different video formats, as well as same formatsbitrate reduction transcoding for the purpose of adapting to the needs of thenetwork and terminals. Firstly, we carried out a detailed analysis forMPEG-2to H.264fast transcoding algorithm, and proposed a variety ofprograms as well as experiments which proved that the effective use ofdecoded macroblock type and motionvector information in the transcodingprocess can promote transcoding efficiency definitely. Then, we focus onH.264bitrate reduction transcoding and H.264to HEVC transcoding,proposing fast inter frame mode decision algorithms based on effective use of decoded macroblock type and motionvector information.The algorithmscan dramatically reduce the re-encoding computational complexity intranscoding process, and improve the transcoding efficiency.Experimental results show that both the proposed algorithms achieveda good balance in transcoding speed and output video quality, andespecially enhanced the transcoding speed by3times and5timescompared with the traditional transcoding methods CCPDT. The resultsindicate that the proposed algorithms provide a feasible solution for thedevelopment of real-time HD video transcoding systems.