【作者】 朱广信；

【导师】 陈彪； 仇佩亮；

【作者基本信息】 浙江大学 ， 通信与信息系统， 2004， 硕士

【摘要】 随着数字压缩技术和IP网络技术的发展，实时多媒体特别是实时视音频的IP网络传输成为了近年来研究的一个热点。在实时多媒体数据中，实时视音频，尤其是实时视频的数据量是非常大的，实时视音频的传输对网络的带宽、延时和抖动等方面都提出了极高的要求。数字压缩技术的不断发展使得视音频信息的数据量大大降低，使得其有可能在现有的IP网络中传输。同时，IP网络自身的性能也在不断的改善，不仅在网络带宽上不断有提高，而且提出了许多支持服务质量方案，使得在IP网络上的实时通信成为了可能。 本文以MPEG-2数据流为对象提出一种嵌入式实时视音频IP网络传输系统的构建方案，在方案中，我们采用了单片MPEG-2编、解码芯片设计了MPEG-2硬件编、解码模块。采用ARM7TDMI内核的网络处理器和开放源码的uClinux构建了嵌入式系统，通过该系统提供了10／100M以太网接口。同时，为了使嵌入式系统能处理实时MPEG-2数据流，我们对其进行了实时数据接口的扩展，包括硬件扩展和驱动程序编写。在此基础上，设计了一种针对MPEG-2 TS(传送流)的RTP／UDP数据封装方法及一种简化处理方法。上述方案经具体设计实现，并在10／100M局域网中通过实际测试，证明是行之有效的。最后，文章分析了IP网络传输对接收端MPEG-2解码视音频的影响，并设计了一些测评方法对系统进行了相关测评。更多还原

【Abstract】 Along with the development of digital compression technology and IP networks, the transmission of real-time multimedia especially real-time video&audio on the IP networks has been a research hotspot in the recent years. In real-time multimedia, the data of real-time video&audio, especially the real-time video are very big. The transmission of real-time video&audio puts forward a very high requirement to the bandwidth, delay, jitter of the networks. However, the development of digital compression technology let the quantity of the data of video&audio decreased greatly, this make the transmission on the present networks become possible. At the same time, the performance of IP networks is improved continuously. It is not only the increase of bandwidth, but also so many schemes put forward to support the quality of service of the networks. These make the real-time communications on the IP networks become possible.In this thesis, we bring forward a scheme to constuct embedded real-time video&audio transmission over IP networks, where the video&audio is MPEG-2 data flow. In the scheme, we design the hardware MPEG-2 encoding module and decoding module with the sigle MPEG-2 encoder chip and decoder chip. We use network processor which is ARM7TDMI core and uClinux which is open source to construct the embedded system. The 10/100M Ethernet interface is provided by the embedded system. In order to make the embedded system process the real-time MPEG-2 data flow, we extend the real-time data interface to it, including the hardware extension and the driver program. Based on above, a RTP/UDP data encapsulation scheme based on MPEG-2 TS (Transport Stream) and it’s simplified process method are designed for the whole system. After concretely design, implementation, and. test on the 10/100M local area network, the scheme is proved to be effectively. At last, the paper analyses the impact of DP network transmission to the the video&audio of MPEG-2 decoder, and designs some measure methods for the system.更多还原