| With the rapid development of multimedia services, transmitting the video of high-quality through the narrow bandwidth and adapting to various networks have become pursuits of people, so a new international video coding standard was released in Mar. 2003, and was jointly being made by ITU-T Video Coding Experts Group (VCEG) and ISO/IEC Moving Picture Experts Group (MPEG), named as joint video team (JVT). This standard was known as ITU-T Recommendation H.264 and as ISO/IEC 14496(MPEG-4) Part 10. Compared with other prior video coding standards, such as MPEG-2, MPEG-4 ASP and H.263, about 50% bits can be saved and more adaptive to various networks with design of 2-layers. H.264 has been gotten much attention from research area and industry all through, but the high-complexity of H.264 has always been a factor of restriction of application mostly. At the same time, the Xscale PXA27x has become the mainstream platform of the mobile terminals such as 3G mobile telephones, PDA and so on. 3G services mainly include mobile television (M-TV) and mobile video phone. Therefore, it is of important significance to study the realization and optimization of the standard based on the Xscale PXA27x platform.In this paper, based on the research of standard and reading of literature, the key technologies of H.264 are introduced first, and the technologies to enhance the efficiency of encoding are emphasized on; then the fast motion estimation algorithm and some practical application experiments of Xscale PXA27x platform are present, based on this, the baseline encoder on PXA27X is implemented. From the point of view of programmer, the methods of optimization on PXA27x are analyzed in detail, these parts, which based on research of experiments; at last, the performance of H.264 in ZTE corp. mobile test platform is given, and from the results of experiment, this encoder, which can realize real-time coding has a good value in practice. Therefore what has been studied should be a promotion to make H.264 work in practice of mobile terminal and in wide use. |
