MPEG-4视频编解码DCT算法的实现研究

【作者】 林潮鑫；

【导师】 张扬； 李立峰；

【作者基本信息】 电子科技大学 ， 电子与通信工程， 2006， 硕士

【摘要】 多媒体通信技术的迅速发展，要求视频通信能在保证质量的同时具有更低的码率。近年来MPEG-4以其低码率、基于对象的交互性等优点在多媒体领域表现出巨大的应用潜力，虽然标准中的部分相关技术还处于开发阶段，但基于简单框架(SP，Simple Profile)的MPEG-4视频压缩标准兼顾了传输码率与视频质量的要求，能在低码率、高压缩比的情况下获得较高的图象质量，因此在现代多媒体通信系统中SP视频框架成为MPEG-4应用的主轴。尤其是随着信息电子和移动通信设备对视频应用的需求增长，低码率视频编解码技术的大量应用以硬件实现为主，尤其是更多的应用到嵌入式设备中，因此本论文以远程网络视频监控系统的开发为背景，重点研究MPEG-4简单框架视频编解码过程的嵌入式平台实现。本文在研究MPEG-4视频关键技术及其特点的基础上，详细分析了MPEG-4 SP视频编解码算法的原理，用C语言程序实现了该算法并在PC机上对程序正确性及其视频效果进行测试，然后在linux操作系统的支持下，基于以ARCA2处理器为核心的嵌入式硬件平台，实现了编解码算法，同时从算法角度针对运动估计和DCT模块提出优化措施，尽可能提高算法的硬件实现速度。系统通过现场视频的测试，解码恢复后的视频利用Framebuffer技术显示，效果较好，同时达到低码率、视频恢复质量高、编码速度快的要求，在多媒体通信系统中有一定的应用价值。最后从芯片设计角度研究了DCT变换编码的ASIC实现，并提出相应的改进方案，在芯片的面积、速度、数据吞吐量上都达到较好的性能，为多媒体处理芯片的开发奠定了基础。全文共分六章：第一章简单介绍了图象压缩的基础理论；第二章对MPEG-4标准视频部分的关键技术及特点做了全面的阐述；第三章详细分析了SP视频框架的算法原理；第四章基于对编解码方案的分析，完成算法的硬件实现，并提出优化措施；第五章针对DCT模块研究算法的ASIC实现，并作出相应的优化改进；第六章简要总结了本论文完成的工作。更多还原

【Abstract】 With the rapid development of multimedia communication technology, low rate and high quality video coding schemes are attracting more attention. In recent years MPEG-4 is showing great values in multimedia application because of its low-rate and object-based interchangeability. Especially simple visual profile of MPEG-4 can efficiently solve the trade-off between bitrates and video quality with relatively simple tools and algorithms, therefore, it dominates MPEG-4 applications among multimedia communication system.To meet the requirements of video application, MPEG-4 SP will be more implemented in embedded equipment. This paper attaches more importance to the embedded implementation and optimization of video coding and decoding in order to complete the development of remote video monitoring system.In this paper, after studying the core technologies and characteristics of MPEG-4 visual part, the principles of MPEG-4 SP are analysed in detail. The C language implementation for these algorithms has been done in order to evaluate the quality of reconstructed video and to validate the correctness of the program.. Then by the embedded development platform based on ARCA2 processor, hardware implementation of algorithms is established. Meanwhile, many optimizations on the two key parts----Motion Estimation and DCT are presented in order to improve the speed of video coding and decoding. The experimental results indicate that the above hardware schemes can meet many actural requirements and have some value in multimedia system. At last, ASIC implementation of DCT is studied and many optimizations or improvements measures are presented, so a solid basement is formed for IC designing of multimedia processing.The thesis is organized as following:Chapter 1 briefly introduces basic theory about video coding and decoding. Chapter 2 analyzes characteristics and main technologys of MPEG-4 visual part in detail. Chapter 3 discusses the principles of MPEG-4 SP algorithm. Chapter 4 presents an hardware implementation scheme on the embedded development platform composed of ARCA2 processor. Chapter 5 completes the optimization and implementation of ASIC on DCT. Chapter 6 gives a brief conclusion of the thesis.更多还原