Optimization On Motion Estimation Of H.264 Based On SSE4 Instruction Set

H.264/MPEG-4 part 10 is an international video coding standard proposed by Joint Video Team (JVT), which is a joint group of ITU-T VCEG and ISO/IEC MPEG Compared with existing video coding standards, H.264 can provide lower bit rates, higher image quality and better adaptability on net transmission. H.264 has been widely applied in a range of fields, such as video compression, digital television broadcasting, and stream media and so on. However, on one hand H.264 provides predominant compression efficiency, on the other hand, it increases coding complexity at the same time. Therefore, how to reduce the arithmetic complexity and accelerate the coding process without decreasing the video quality is a hot spot in the video compression field.Firstly, in this dissertation the background of research in video compression, the development of video coding technology, the existing video standards and the state-of-the-art of H.264 video coding standard are expounded. The framework of encoding and decoding and the key technologies of H.264 are discussed in the dissertation. The fast motion estimation algorithms, the principles of macro block matching as well as the mode decision principle are discussed. Then this dissertation makes an in-depth research on four classic motion estimation algorithms, which are Full Search Algorithm, EPZS Algorithm, UMHexagonS Algorithm and Simplified UMHexagonS Algorithm. On platform of JM10.2 of JVT, the four classic motion estimation algorithms are used separately to encode one YUV file. According to the experiment data, these four motion estimation algorithms are compared. The result shows that Full Search Algorithm has a most accurate image state and a simplest estimation algorithm, while the other three motion estimation algorithms can increase the coding speed compared with the Full Search Algorithm. Simplified UMHexagonS Algorithm has an optimal performance in these four algorithms.Secondly, this dissertation makes a brief introduce about the development history of SSE instruction set. Two instructions, MPSADBW instruction and PHMINPOSUW instruction, are in-depth discussed. These two instructions can be used together to improve video encode. The parameters, calculate methods and results in return of these two instructions are analyzed. On platform of JM8.6 of JVT, MPSADBW instruction and PHMINPOSUW instruction in SSE4 instruction set are used together to calculate SAD with higher speed, which shows that SSE4 instruction set can improve fast motion estimate optimization of H.264.Thirdly, on platform of JM8.6, SSE4 instruction set is used to improve the fast motion estimate optimization. Compared with the Full Search Algorithm on platform of JM8.6, the parameters such as:ΔPSNR, ABits,ΔTime are calculated. The experimental results show that, the optimization algorithm on motion estimation of H.264 based on SSE4 instruction set proposed in this dissertation can save 18%-30% total encoding time without significant image degradation or bit rate increasing. The proposed algorithm can get better performance in encoding video sequences with less motion intensity.Last but not the least, summary of this dissertation is concluded, and vista is depicted. Combination of optimization algorithm on motion estimation and SSE4 instruction set, as well as the platform of T264 are taken into consideration for future research.