Algorithms Optimization Of Core Parts In H.264 And Encoder's Transplantation On DSP

H.264 is a new generation of international standard of video coding, which gained an approval in May, 2003. In contrast with the former standards, H.264 has distinct features: its compressibility is about twice as strong as H.263 or MPEG-4. The stronger compressibility, however, is due to its high complexity which limits the application of H.264. In coding, its complexity is reflected in inter-prediction modules; while in decoding, it lies in the decoding of the information entropy. Therefore, in order to accelerate the coding and decoding speed, it is necessary and important to optimize these two modules. As for inter-prediction part, this paper proposes intra-prediction selection decision which can effectively cut down intra-prediction computations in inter-prediction modules so that the speed can be accelerated by 10%. For information entropy part, this paper puts forward CAVLC decoding method that can accelerate the decoding speed to a large extent in the given storage space.TMS320DM642, a multimedia processing chip, which was produced by TI Corporation, is mainly and widely applied to audio-visual coding and decoding process. This paper is to introduce the optimization of H.264 Baseline coder based on DM642. First, the complex modules are calculated by means of the evaluation tools. Second, the simple functions frequently used in the modules are optimized by using C language and assembly language so that the general coding speed can be accelerated. What is noteworthy here is that the optimization should take software pipelining and parallel joint techniques into full consideration according to the structure of DM642.The optimized coder can be applied to the coding of QCIF images which have 32-42 frames. And the decoded images by the approaches provided in this paper do enjoy high quality both in subjectivity and objectivity in our experiments.