【作者】 邱忠权；

【导师】 彭强；

【作者基本信息】 西南交通大学 ， 交通信息工程及控制， 2003， 硕士

【摘要】 随着数字技术和通讯技术的发展，图像视频编码技术和编码标准也得到了长足的进步。H.26L便是目前面向无线通信和多播的低码率视频传输标准的最新版本。该标准具有压缩率高、差错恢复能力强、适用范围广等优点。为达到理想的数据压缩率，H.26L编码器采用了很多新的编码算法，这些算法极大地增加了编码器的计算复杂性，使其目前在PC环境下的实时应用受到很多限制。在要加速H.26L的实时编码速度，一个行之有效的方法便是采用MMX技术对其执行时间最多、执行次数最多的部分代码进行优化，以减少编码时间。本文以H.26L的测试模型TML8.0为实验平台，对其编码器进行了详细的分析和性能测试，找出最值得优化的程序代码，并在此基础上采用MMX技术对其进行优化，加快编码速度。本论文主要包含以下内容： 1、简要介绍了视频编码的基本方法和H.26L编码标准的主要特点和新引进的算法；并对MMX技术相关知识进行介绍，说明MMX技术进行优化的步骤。这部分知识是进行本论文研究的基础。 2、通过对H.26L视频编码的基本原理以及H.26L编码器程序TML8.0的分析及测试，找出H.26L视频编码中耗时最多、执行次数最多的模块。 3、对以上找出的模块进行MMX优化，并对其试验结果进行了分析和对比。通过从对整像素搜索的优化效果的分析，得出不必对1/2像素和1/4像素搜索进行优化的原因。 分析和试验表明，通过MMX优化的方式可以很大程度的提高H.26L视频编码的处理速度，使得该标准可以更好的适用于PC机环境下的多种不同的视频应用。更多还原

【Abstract】 With the development of digital technique and communication technique, multimedia video coding technique and corresponding coding standard are developing accordingly.H.26L, a video-coding standard proposed by ITU, is the latest standard for video communication and multicast in low bit rate conditions. H.26L has such advantages as high compression rate, strong error resilience capacity, high adaptability and so on. In order to gain good coding result, H.26L adopts so many new algorithms that the amount of computing increase greatly. As a result, its applications in PC environment are restricted. In order to accelerate H.26L real-time coding, MMX technique might be effectively used to optimize part code that takes the most time and executes the most times, which may help to decrease the coding time.Based on the test model long-term 8.0(TML8.0) of H.26L and through a detailed analysis and capability test of the encoder, the present paper finds out the code that is worthy of optimizing and it also finds out the way to optimize the code and accelerate coding by using MMX technique. The main contents of the paper are as follows:1. The thesis gives a brief introduction to basic ways of video-coding, the main features of H.26L vide encoder, primary theories, and the correlative knowledge of MMX technique. The optimize step of MMX technique was introduced as foundations of this paper.2. The paper points out that the module that takes the most time and executes the most times can be found out through the analysis of the basic principle of H.26L Video Coding and coding procedure TML8. Oof H.26L coder.3.The present paper optimizes the above-mentioned module by using MMX technique, analyzes and contrasts the result of examination. We can see the reason why we need not optimize the half pixel search and quarter pixel search by analyzing the optimizing effect of integer pixel search.The analysis and simulation results show that MMX technique can greatly speed up the processing of H.26L encoder and make it possible for the H.26L to be used in PC environment in many video applications.更多还原