Video Transcoding System Design Based On DaVinci Platform

The development of video compressing standards and the wide application of various multi-media terminal units accelerates the development of video transcoding technique. It's absolutely necessary to convert the format of video to another in order to meet different needs of different users. This is why video transcoding technique comes forth. Traditional video transcoding technique can be classified into three kinds, which are bit-rate transcoding, resolution transcoding and syntax transcoding. And the last one is applied in this dissertation.The rapid development of embedded video applications put forward higher requirement for video processing chips. On the one hand, they must have sufficient computing power. On the other hand, they must have strong control function. TI released DaVinci technique and relevant products, which solve these problems perfectly. This thesis is based on TMS320DM6467, one of DaVinci products, of which the special component HD-VICP provides conditions to achieve real-time development of this transcoding system.The most straightforward transcoding architecture is to cascade the decoder and encoder directly. This kind of architecture is flexible and has good real-time quality but complex. Significant complexity saving can be achieved while still maintaining acceptable quality, by reusing information contained in the original incoming bit stream, including motion vector, macroblock encoding mode and frequency domain information. AS it is certain to meet real-time needs with the help of HD-VICP of DM6467, this thesis adapts the cascading architecture at last.First, this dissertation discusses the development of video transcoding technique and the formation of DaVinci. The technical background is put forward in this part.Then the DaVinci platform is presented and the concept of DaVinci technique is introduced. The multi-media processor TMS320DM6467 with C64x+instruction set is also introduced, which is adapted in this dissertation.In the following part, the algorithm of the transcoding software is brought forward. The software framework and the detail components, such as TS demultiplexing part and spatio resolution converting part, are introduced.Then, the dissertation discusses programming and optimizing of the transcoding software based on DaVinci DSP in emphases, which is dissertated from the views of code transplanting, C optimizing and assembly optimizing. As to the part of C optimizing, various kinds of measures are applied,with the effects showed to readers. Details are also discussed about configuration and using of Codec Engine.The final part of the dissertation is about some conclusion and future work.