Study On H.264/AVC Real-time Encoder System And Correlative Algorithms

In the past about ten years, a series of international video coding standards are developed and widely used in a variety of domains. Some standards for real-time telecommunication applications have been established by ITU-T, including H.261, H.263 and later enhancements of H.263 known as H.263+ and H.263++, Others for video storage, broadcast and stream applications by ISO/IEC, such as MPEG-1/2/4. H.264/AVC is the newest standard approved by the ITU-T and ISO/IEC organizations, which represents a number of advances in video coding technology and becomes the newest international video coding standard because of both high coding efficiency and network friendliness.The design of H.264/AVC is based on conventional block-based motion-compensated hybrid video coding concepts, but with some important differences relative to prior standards: enhanced motion-prediction capability; a small block-size exact-match transform; adaptive in-loop deblocking filter; enhanced entropy coding methods. The experiment results show that the improved coding efficiency, up to 50%, comes with a complexity increase of more than one order of magnitude at the encoder. In fact, a proper use of the H.264/AVC tools leads to roughly the same performances as the complex configuration. So both computational complexity and coding efficiency should be thought and made to the optimal trade-off in the implementation of actual coding system.The new features of H.264/AVC increase not only the complexity of coding basic modules, but also the one of algorithms by times. The multimedia instruction may be used to optimize the basic modules; the fast algorithms are developed instead of the old ones. This dissertation is based on the above methods, and major works are as follows.To reduce the complexity of intra prediction, a fast intra-prediction mode selection algorithm is proposed. It uses the mode selection correlation between chroma block and luma block, the correlation between luma 4x4 block and luma 16x16 block and the selection correlation in luma block modes with different criterions(RDO(Rate Distortion Optimization) or SATD(Sum of Absolute Transform Difference)) to fast determine the best mode.To reduce the complexity of inter prediction, a fast inter mode decision algorithm is proposed. It classifies all modes by both homogeneity and space-time correlation of macroblock. The SKIP mode can be early terminated, and other modes can be compared type by type. So the number of calculated modes can be decreased efficiently.To reduce the complexity of motion estimation, a fast integer pixel motion estimation algorithm combined with the new features introduced by H.264/AVC is proposed. It analyzes relevant motion vectors of current block to determine search range and direction, and designs effective search path, which can efficiently decrease the number of search points and come to a good matching.To reduce the complexity of multiple reference frames, a fast selection algorithm of reference...