Avs_m Algorithm Optimization And Its Realization On The Dm642

With the development of computer and network technology, multimedia communication such as image, music and video transmission has come into people's life. Now in the world, MPEG and H.26x are the most popular multimedia compression protocols. Since using these two standards have to pay expensive royalty, our country has developed our own AVS (audio and video coding standard) with independent intellectual property right.The seventh part of the standard AVS_M (audio video coding standard -mobile) is developed to adapt the mobile communication needs. It is mainly used in the multimedia storage, communication and small image show in the 3G. Because of low CPU processing speed on PDA, how to improve decoder's speed is the most important problem we need to solve.In this paper, we introduce background and significance of the subject, and describe framework and major technologies of the codec. Then we do optimization work based on the source code WM2.7. The optimization processing has two steps.First, algorithm is optimized on PC. Through analyzing time complexity, we get that sub_pixel interpolation algorithm is bottleneck of the decoder. We propose process improvement methods and data load methods. Experimental results show that these methods have enhanced the decoding speed to 1.5 times compared with original one.Second, the decoder is realized on DM642 system. Port the code to embedded system according to CCS(Code Composer Studio) compiler's characteristics. Through analyzing memory manager structure, we improve cache organization, data research method and data least_wait solution. Experimental results on EVM show it has satisfied real-time decoding requirements.