【作者】 曹华；

【导师】 严国萍；

【作者基本信息】 华中科技大学 ， 电路与系统， 2008， 硕士

【摘要】 随着数字视频压缩技术在网络监控领域的应用越来越广,人们对高质量的视频压缩算法实用化的需求也越来越迫切。MPEG-4是一种新近成熟的、高性能的视频编码标准。与其他编码标准相比,它的压缩效率更高,程序结构更清晰、应用更灵活。在网络监控系统中使用这种视频编码标准,能够给用户提供高清晰的视频图象。本课题针对网络视频监控系统的实际需求,在以TMS320DM642 DSP为核心的硬件平台上,研究并开发MPEG-4视频压缩编码器。论文介绍了网络监控和视频处理的背景知识,分析了MPEG-4简单框架编码技术的基本原理和编码流程,研究了其中的离散余弦变换、量化、宏块预测、运动编码等关键算法,以及它们的实现方法。论文详细介绍了工程级、C代码级、汇编级等各个级别的程序优化方法,研究了C64X IMGLIB图象处理函数库中的函数在本程序中的应用。在此基础上,结合DM642的硬件特点对MPEG-4编码程序中耗时较多,且被频繁调用的代码进行了优化。文中还介绍了CCS及DSP/BIOS工具的功能和应用,在此基础上结合DM642的有关接口资源讨论如何实现数据传输和编码的同步进行。为了验证优化的效果和视频编码软件的整体性能,本课题通过标准视频序列,用代码剖析器对程序进行了测试,比较了优化前后的代码长度和运行时钟周期,并根据测试数据计算出所能达到的编码帧率和压缩率。最后,论文对课题进行了总结和展望。更多还原

【Abstract】 With the implementation of video compression widely spreading in the field of network monitoring, the realization of better video compression algorithms is urgently required. MPEG-4 is a newly developed video coding standard that gives outstanding performance. Compared to other related tandards, MPEG-4 provides higher compression ratio, more orgornized programming structure, and more flexibility for implementation. Employing this outstanding video coding technology, the network monitoring system will offer the users vivid images. The task of this thesis grounded on the practical requirements of network video monitoring system, is intended to research and develope MPEG-4 video compression encoder on the TMS320DM642 DSP hardware platform.The thesis introduces fundamental concepts of network monitoring and video processing, analyzes MPEG-4 simple profile encoding technology, research the important algorithms such as Discrete Cosine Transform, Quantization, Macro Block Prediction and Motion Coding.The thesis is particularized on introducing the program optimization methodology on project level, C language coding level, and assembly language level, as well as analyzing the implementation of the functions in the image processing library C64X IMGLIB. On those bases, the frequently used code areas that comsume a large amount of time are optimized according to the hardware features of DM642. The functions and applications of CCS and DSP/BIOS are also introduced. The realization of synchronization of data transform and encoding are discussed.Finally, the encoder’s performance and the effect of optimization are tested using standard testing sequences, and the frame rate and compression ratio are calculated. The summary and advice for further reseach are offered in the end of this thesis.更多还原