Research On H.264 Coding Model And Rate Control

With the rapid development of computer network and wireless communication, the demand of multimedia service is increasing, video-coding technology becomes more and more attractable to people and have been a bottleneck of multimedia application. The research of video coding mainly includes two fields: the design of source model and the choice of coding mode. The former finds the statistics of the source and provides efficient coding tools in the coding standards while the latter chooses the best coding modes for different video sequences, which is deeply researched in the thesis. Supported by the National High Technology Research and Development Program of China (863 Program)–Joint Source-Channel Coding (No: 2002AA119010), this thesis focuses on the development of the coding model and rate control technique of H.264.H.264 is the new standard developed in March in 2003 by ITU and MPEG. We first discuss the key technique in H.264 including system framework, transform, inter-prediction, intra-prediction entropy coding and block filtering. And with a deep research of the quantization and transform and the analysis of substantive experiment results, we present a coding model based on valid-bit-number, which can precisely describe the results of practical coding and is proved to be consistent with the theory analysis.The rate-distortion optimization method in H.264 can efficiently improve the performance of the practical coder. We make a deep research of the relationship of the rate-distortion optimization method and the rate control in video coding and analyze the close-loop correlation of them and the rate control function of the rate-distortion optimization method. Base on such research, we present a two-level rate control framework, which is tested with experiments. With the research above, a new rate control algorithm is given, which is based on the valid-bit-number coding model and the rate-distortion optimization technique. We realize it in the H.264 coder and the test results prove it applicable.Finally, the design and implement of videoconference system is summarized and the key network transmission and video coding techniques are introduced.