| In the past tens of years, study on the digital video coding technology has never ceased. Various techniques in video coding and decoding become applicable. Especially in the latest several years, a lot of new video compression standards were established for different purposes, which finished the era of MPEG-2. Video coding standard plays a key role in many fields, such as digital TV, IPTV, video conference and multimedia communication, etc.AVS-M video coding standard is developed by the Audio Video Coding Standard Working Group of China. AVS-M standard provides good trades-off between compression rate and computation complexity (about 70% of AVS video coding standard). It introduced a number of advanced video coding techniques, and offered error resilience and net adaptation ability. Research on AVS-M coding technology offers great importance in developing multi-media applications on mobile platform.A fast implementation of encoder is of great importance for the practical use of AVS-M standard. This paper briefly introduced the development of the audio/video coding standards in the world and the major coding technologies used in these standards, and then studied the key technologies in the AVS-M video compression standard. Finally the AVS-M reference encoder was optimized on IA-32 architecture.The optimization is based on the AVS-M reference encoder. The major optimization strategy includes adjustment of the program and data structure, and rewriting of the most time-consuming functions with Intel SIMD instructions. Adjustment of the program structure includes the following parts: intra prediction, motion estimation, DCT, IDCT, quantization, de-quantization and rate distortion optimization etc; Adjustment of the data structure includes the program control data and computation data structure. They were adjusted to avoid redundant data calculation and to use SIMD instructions. After rewritten these functions, the encoder is accelerated with no descendant of picture quality and bit-rate. |
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