The Optimization And Implementation Of H.264 Encoder Based On TMS320DM642

H.264/AVC video encoding standard was constituted jointly by two great international organizations, ITU and ISO/IEC. As the most advanced video encoding standard which was based on H.264 standard video encoding technology, it becomes more and more widespread in practical applications. In order to adapt the difference between different applications and network, the overall framework of the H.264 standard can be divided into two layers:Video Coding Layer (VCL) and network abstraction layer (NAL). VLC layer is for effective encoding indication; it is designed to improve the encoding efficiency. NAL layer is for the transmission of video data on different network. It had an effective solution on adapting the quality of service (QoS) between video and network.TMS320DM642 was introduced by TI as a high-performance digital signal processor which mainly deals with digital media in 2003. It was based on the C64x core with a wealth of video and audio hardware resources on the chip. It has great performance on visual telephone, video surveillance and other multimedia applications.In this article, the open-source H.264 standard encoder X264 was transplanted to TMS320DM642 digital signal processor. By studying the H.264 standard and open source code X264 then making full use of DM642's hardware and software, the X264 characteristics were optimized. Optimization was proceeded from following three levels. First, project level optimization, adjust and delete the original code according to the difference between DSP platform and PC platform. Achieve the initial optimization through the CCS compiler options and other methods. The second step is the algorithm optimization, through analysis of existing algorithms, found that motion estimation cost most the time in the entire encoding process. So adopt the improved fast motion estimation algorithm to enhance the computing speed of motion estimation. Finally, it's instruction-level optimization, this section mainly used inline functions, Chip Support Library (CSL) module function, loops and software pipelining methods that provided by TI to achieve the optimization. The purpose of enhancing the efficiency of H.264 encoding is got by the three levels optimization.