| Along with the rapid development of Internet and mobile communication, the processing and transmission technologies of video and multimedia information in the Internet and mobile network become hot. H.264/AVC is the newest standard approved by the ITU-T and ISO organizations because of both higher 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 prediction capability; a small block-size exact-match transform; adaptive in-loop deblocking filter and so on. Inter-frame encoding technology is the key technology of video coding standard, it accounts for about 50 to 80 percent of the whole encoding computation, so it is the most challenging research topic in video encoding and the core of my thesis.Firstly, the basic theory of the compress coding is introduced. And then the framework and new features of the H.264/AVC standard are given. Secondly, the research on the algorithm based on Rate Distortion Optimization is done. Rate Distortion Optimization strategy is a cost function which is proposed based on the rate distortion theory. The strategy is imported into the H.264/AVC and then applied reasonably by motion estimation, reference and mode decision. The experiment results show that compared with conventional cost function, the coding performance is improved much more. Thirdly, the research on motion estimate search algorithm. Many kinds of conventional algorithms are introduced and analyzed. Then according to the new features of H.264/AVC, Hybrid Unsymmetrical-cross Multi-Hexagon-grid Search algorithm is introduced and experimented. Based on that, a fast search algorithm based on vector prediction is proposed and experimented. The combination estimation of the subjective and objective evaluation criterion of the results shows that the algorithm can raise coding rate while the character of R-D keeps the same. |
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