基于MMX技术的H.264解码器优化

新一代视频编码标准H.264为了提高编码效率采用了一系列新技术，而这些新技术的使用也极大地增加了算法的复杂度。因此，在保持编码效率的同时如何提高编解码器的运算速度成为目前研究的热点问题之一。介绍了符合H.264基本规范的解码器的基本框架和解码流程；通过复杂度分析确定了解码过程中计算最为密集的两个模块，即插值、整数余弦变换和重建模块；提出了基于MMX技术的优化方法，并对这两个模块进行了重点优化。实验结果表明，利用这些优化方法可以使解码器的平均解码速度提高到原来的1．4-2．1倍，优化效果十分显著。

H.264 decoder optimization based on MMX technology

New video coding standard H. 264 achieves high coding efficiency through adding new features and functionalities. However, such features and functionalities also entail additional complexity in encoding and decoding. Therefore, improving the calculating speed becomes one of the hot topics in research area. The basic framework and the decoding process of H. 264 baseline decoder are introduced. Further two most computational intensive modules, that is, interpolation module as well as integer cosine transform and reconstruction module, are figured out by the complexity analysis in order to provide foundation for the following optimization. By making full advantage of MMX technology, most optimization efforts are emphasized on these two modules. At last, conclusions can be made after analyzing the presented results of computer simulation, that the proposed algorithms are prominent while 1.4-2.1 times average decoding speed can be achieved after optimization.