The Dm642-based H.264 Network Video Encoders

Today, with the fast development of multimedia and network communication technologies, embedded multimedia transmission system get more and more extensive applications. The research and development of embedded video communication system have a very large scientific value and practical significance. With the development of VLSI, it is possible to run high computational complexity of video compression and network transmission on one single DSP chip. Using the current advanced video coding compression standard H.264 for compression, use TCP/IP protocol stack for transfering video data act as one of the best schemes of the embedded video communication system.On the base of deep study of the H.264 standard and the TCP/IP protocol stack, a video coding transmission system which is based on Texas Instruments Corporation's TMS320DM642 DSP chip was proposed. The driver of network physical device was programmed, a small and simple TCP/IP protocol stack was designed and constructed, and Server/Client program was completed. The camera captured analog TV signal, after down sampling the signal, the H.264-encoder packed compressed video data using the RTP packets, sent to PC to decode. This TCP/IP protocol stack has the characteristics of a small number of codes, fast rate, flexible to modify, and make some improvements in view of the characteristics of the H.264 stream.At last, the H.264 encoder has been optimized from the algorithm level to the program level. A fast intra prediction algorithm was proposed, reduced the candidate modes and greatly increased the encoding speed with barely PSNR decline and small rate increase and the fast skip mode judge to reduce the complexity of inter prediction. Encoder process framework was modified, and combined with the characteristics of DM642, optimization measures such as memory allocation, variable redefinition, software pipelining, inline functions was introduced.The H.264 video encoding and transmission system with a feature of real-time video capture and transmission can be used as the core module of the video surveillance system, video conference system and etc.