Realization And Optimization Of MPEG-4 Video Compression Based On DM642 For Net-Camera

Along with the development of society and the progress of technology, video transmission is more and more widely applied, especially in the field such as image telecommunication, video monitor, network stream-media and IPTV. Net-camera is the main equipment in video monitor system, and video compression is the key technology of net-camera. TMS320DM642 of TI chosen as the core processor of net-camera has great advantage, while MPEG-4 is a maturely developed video compression standard with low complexity. In this paper the work is starting around realizing and optimizing the MPEG-4 encoder in DM642.In this paper we firstly introduce the conception of video signal, base principle of video compression, and some video compression standard, and then fix on some aspects for the object of optimization by analyzing the MPEG-4 algorithm.Secondly, we propose the improved APDZS algorithm by analyzing and comparing the APDZS, MVFAST and PMVFAST algorithm. The main idea of improved APDZS is as followed two. One is reducing the count of search point by using the information of current MV, and the other is setting the suitable threshold range according to the motion degree of coded video object. The result shows that the performance of the proposed algorithm is comparable with other algorithm such as FS, APDZS, MVFAST and PMVFAST, in terms of both PSNR-Y and bit stream length, with less searching complexity.Thirdly, we transplant the MPEG-4 encoder into DM642, and optimize it based on DM642. The performance of encode is great improved by using software pipeline, and the encoding speed is further improved by using system function, EDMA, ping-pang memory structure, inline function and some compile options.Finally, we propose an idea how to make the MPEG-4 encoder as one of member in the net-camera software system which is satisfied with TI RF5 reference framework. During integrating, we design some data and function interfaces accord with the component such as SCOM, CHAN, ICELL, ALGRF and IDMA2. As a result, the MPEG-4 encoder can successfully run in the net-camera software system.