Research And Otimization On Motion Estimation Algorithm Based On H.264/AVC

H.264/AVC is the video coding standard jointly developed by ITU-TVideo Coding Experts Group(VCEG)and ISO/IEC Moving Picture Experts Group(MPEG). To compared with the previous coding standards, the most prominent feature of H.264 is high compression ratio, but also it has a good network of affinity, suitable for low-bandwidth, high-quality network video applications. Superior compression performance of H.264 is based on highly complex calculation. Motion estimation is one of the mainly technology for the video compression coding, in which the encoder calculation of the total amount of 60%～85%, and with the motion compensation technology they can eliminate time redundant of video signal to improve the coding efficiency. As a result, how to improve the efficiency of motion estimation to make the search process more robust, faster and more efficient becomes one of the hot spots of the current study.This paper first discusses the basic principles and key technologies of H.264 video coding standard; then introduces several existing classical Block-Matching Motion Estimation algorithm and analyses their strengths and weaknesses respectively; whereafter, in depth analyses the H.264 recommended core algorithm of motion estimation-UMHexagonS. Aimed at improving the lack of motion estimation algorithm, four aspects of the algorithm were optimized, which are identification in the initial search point the location of the reference search range, the dynamically generation of reference search range size as well as big hexagon and small hexagon search mode. Optimized UMHexagonS algorithm can fast and efficient identify the location and size of the reference search range. The improving big and small hexagonal search mode in the entire search process can significantly reduce the number of search point and achieve a better match results.Finally, the simulation carried out experiments proves the thesis in the improved algorithm. The optimized algorithm is realized in the H.264 reference software model JM10.1, compiled by VC6.0. Experimenting with a variety of movements with small, medium and large movement characteristics of sports video typical video sequences proves that, compared to UMHexagonS algorithm, our optimized algorithm can save about 17.2% ME time and reduce the complexity of original scheme as well as enhance the real-time performance of the encoder but has almost no changing in the reconstructed picture quality and bitrate.