【作者】 叶勇杰；

【导师】 高仕斌；

【作者基本信息】 西南交通大学 ， 电气系统控制与信息技术， 2007， 硕士

【摘要】 随着网络通信技术和多媒体技术的发展，视频编码和传输已经在许多领域取得了成功的应用，基于嵌入式的视频系统在近几年也成为研究和开发的热点。而嵌入式系统设计突飞猛进的发展为这一热点提供了条件。开发数字视频系统主要的工作是视频信号的采集、压缩、传输和解码显示。视频信号是数据量庞大的信号，因此编解码是系统中最耗时的两个工作模块。本文选择MPEG-4编码算法来进行视频信号的压缩，深入研究了视频数据的空间格式、时间格式、帧内图象压缩(DCT，Quant，VLC等)、帧间运动估计和运动补偿等算法，并进行了改进和优化。本文在VC环境下编写代码验证了算法的可行性：软件实现精简的RTP传输协议，对压缩的视频数据进行传输。算法的复杂性和编码的实时性，使得传统的软件编码设计不能满足要求。市场上通用的硬件编码芯片，例如IME6400、ADV611等可以快速、高效、便捷地实现视频编码，但是缺乏灵活性。利用嵌入式DSP的高速计算能力可以充分的实现编码算法，且升级方便。本文基于高速数字多媒体处理芯片TMS320DM641，进行嵌入式网络视频编码器的研究，充分考虑了DM641的CPU性能和丰富外设，提出了系统的实现方案，并根据DSP体系结构和开发环境(CCS)，对MPEG-4视频编码算法、RTP传输协议、乃至整个软件系统进行多方面的优化，使得系统提高了速度，满足基本的需求，也为系统的升级打下基础。更多还原

【Abstract】 With the development of network communication technology and multimedia technology, encoding and transmission of video has been applied in many fields. And the embedded video system was also a hot topic research, recently. The advanced rapid development of embedded system correctly fit this research.The main works of developing digital video system are about video signal’s collecting, encoding, transmission, decoding, and displaying. Signal of video is very enormous, so encoding and decoding are the most time-consuming parts in the system. In this paper, we use MPEG-4 to encode video signal. The works are researching of video signal data’s format and study of several arithmetic, such as: image compressing(DCT, Quantization, VLC, etc), Motion Estimation(ME) and Motion Compensation(MC). We give some advices about improvements and optimizing. All of the works has been validated under Visual C ++, and we wrote a tidy RTP stack to transfer the encoded video data.As we know, the encode arithmetic is complicated, and encoding must work in real time, so it’s difficult to finish the work by traditional software encode design. There are many hardware chip such as IME6400、ADV611, which can encode video data very fast, efficiently, and easily. But hardware is not flexible. Embedded DSP can execute encode arithmetic program easily, because of its great ability in high-speed calculating. And we can upgrade the software conveniently. In this article, we research the embedded network video encoder based on TMS320DM641, which is a high-speed digital multimedia process chip. With consider of DM641’s structure and abundant peripheral, the video monitoring system is designed. In allusion to DSP’s structure and compile environment, We optimized the MPEG-4 video encode arithmetic, RTP stack, and so on. Our works accelerate the system, meet the requirement of video monitoring system, and make a good base of upgrading for the system.更多还原