Research On Rate Control Algorithm Based On H.264/AVC

H.264/AVC video coding standard is provided formally by JVT (Joint Video Team) in March 2003, and it will be the second successful video compression standard after the MPEG-2/H.262. The standard is designed to give a new technical solution to a broad range of applications, such as very low bit rate conversational services and low delay broadcast, interactive video services etc. So this standard obtains much attention from academic and industrial fields. The main object of video coding is to minimize the distortion subject to a constraint bit rate. Rate-distortion analysis and rate control play a key role in video coding and communication systems by providing the best optimized compression performance, assuring the successful network transmission of the coded video data, and achieving the best visual quality at the receiver. The research on video coding mainly includes two fields: the design of coding 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. This thesis focuses on the rate-distortion optimization, the coding model and rate control technique of H.264.Firstly, we discuss the key technique in H.264, including system, transform, inter-prediction, intra-prediction, entropy coding, block filtering and rate control. And with a deep research on rate-distortion optimization. The rate-distortion optimization method in H.264 can efficiently improve the performance of the coder. We make a deep research on the relationship of the rate-distortion optimization method and the rate control in video coding and analyze the close-loop correlation of them.Secondly, the mechanism of the rate control and coding model is described. Considering the character of H.264 bit stream, we analyze acoding model based on valid-bit-number, which can precisely describe the results of practical coding.Lastly, we introduce three classical methods of rate control algorithm, and analyze the rate control algorithm in H.264/AVC JM7.6. With the research above, a new rate control algorithm is realized by C, 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.