【作者】 王丽莉；

【导师】 张国印；

【作者基本信息】 哈尔滨工程大学 ， 计算机应用技术， 2007， 硕士

【摘要】 现阶段视频通信领域，存在多种编码标准，由不同的组织，针对不同应用、场合制定，其中，ISO/IEC制定的MPEG-2标准在固定多媒体通信中得到了广泛的应用，在硬件、软件以及多媒体数据存储上都有巨大的积累，但在很多场合，MPEG-2编码数据并不适用，例如，无线移动网络、无线视频会议系统等。与MPEG-2相比，AVS具有更高的编码效率、能够支持更广泛的应用以及不受专利产权的困扰等优势。在这样的情况下，直接将现有大量的MPEG-2视频流直接变为AVS的视频流是有效的解决方案。本论文首先简要介绍了视频转码技术的研究背景和研究现状，并阐述了本文的主要研究内容及主要工作。其次，对MPEG-2和AVS的视频编码标准，尤其是MPEG-2的解码过程和AVS的编码过程进行了研究，通过比较分析，找到了两种标准的异同点，为MPEG-2到AVS视频转码器的设计做好了知识储备。再次，简要分析与比较几种主流视频转码器的结构与性能。针对MPEG-2和AVS两种标准的异同点，提出了一种改进的基于像素域的级联式MPEG-2到AVS视频流转码方案。同时详细研究与分析了在实现该转码器过程中涉及的关键技术环节以及所用到的算法。接着，为了缩短转码时间和提高转码质量，对AVS编码器的性能进行了优化。在分析了各模块运算耗时情况后，对其中运算量最大、最耗时的运动估计和模式选择提出了快速算法。最后设计并实现了MPEG-2到AVS视频转码系统。实验表明本文的转码方案在兼顾转码后视频质量的同时，较大的加快了转码的速度，达到了实时转码的要求。更多还原

【Abstract】 Currently there are a variety of encoding standards in different cases, aiming at different application evelopments occasion in video communications, in which MPEG-2 standard established by ISO/IEC has been widely applied in immobility multimedia communication and has huge accumulation in hardware, software and multimedia data storage. MPEG-2 data is not applicable in many cases, such as wireless mobile networks and wireless video conferencing system. Compared with MPEG-2, AVS has higher coding efficiency, can support wider use and property rights and doesn’t have the trouble of patents right and so on. So, convert lots of MPEG-2 video stream directly to AVS Video stream is a most effective solution.Firstly in this tesis, the video transcoding technology research background and current status of research is introduced, the main content and our main tasks is proposed.Secondly, the MPEG-2 and AVS video coding standard, particularly the MPEG-2 decoding process and the AVS encoding process are researched. Through a comparative analysis similarities and differences between the two standards are found, which supplies knowledge reserves with the design of the transcoding device from MPEG-2 to AVS.Thirdly, the structure and properties of several mainstream video transcoding devices are briefly analyzed and compared. Aiming at the similarities and differences between MPEG-2 and AVS standards, an improved, based on the pixel field and cascade transcoding program from MPEG-2 to AVS video stream. On the same time, the key technology sectors and the algorithm used in achieving transcoding process is detailed analyzed and discussed.Fourthly, in order to shorten the time to transcode and improve code quality, the performance of the AVS encoder is optimized. After the analysis of the computational time of each module, aiming at the largest amount of computation, the most time-consuming and patterns choice, a fast algorithm is proposed.Finally, the PEG-2 AVS video transcoding system is implemented in this paper, in which the research and improved algorithm are appplied reasonably. Through the test, the fact that the program of this paper greatly accelerates the rate of transcoding and takes into account the video quality after transcoding is demonstrated.更多还原