摘要
随着移动通信技术飞速发展以及手机等移动终端处理能力的提高,人们不再满足于仅有的文本,声音和图像信息的交流,还希望能够随时随地得到视频媒体的信息的服务。移动多媒体被认为是3G通信时代的重要服务。以3G移动多媒体业务为代表的无线多媒体业务已经在韩日,欧洲等国家和地区取得了一定的成效,我国的3G业务也即广泛开展。
移动流媒体是流媒体技术在移动网络和终端上的应用,主要利用目前的2.5G和3G的移动通信网,为手机终端提供音频,视频的流媒体服务。它是无线通信和多媒体通信技术的结合产物。
论文详细分析了无线流媒体传输系统的几个关键技术,分别是无线流媒体的传输控制协议,无线网络的QOS控制策略以及整个系统的软件架构;其中无线流媒体传输控制协议包括RTSP/SIP协议,RTP/RTCP协议;无线流媒体Qos控制策略主要是在研究了几种基于RTP/RTCP协议的自适应控制算法的基础上,提出了一种了基于MSB缓冲区的拥塞控制算法。
论文的主要工作包括:实现了适合于移动平台的嵌入式流媒体RTSP/SIP简化协议栈并且改进了RTP的组包方案;为了保证无线网络视频传输的实时性以及视频回放质量,在客户端设计了基于缓冲区的拥塞控制模块和丢包处理模块:在缓冲区模块中,通过动态调整客户端缓冲区的大小来改变视频传输的延时,并且通过与服务器端通信来监测当前网络状况;丢包处理模块是对包的丢失和不完全的帧进行处理,避免了视频回放的抖动以及马赛克现象的发生。最后论文给出了基于无线网路的视频传输系统实例和测试结果。
With the rapid development of moblie communication ,people not only need communication with texts, oices,images, but also need multimedia information services those can be provided anywhere anytime. Mobile multimedia services are thought to be important services in 3G communication age. Wireless multimedia services, especially 3G mobile multimedia services have been widely applied in Korea,Japanesse,and some countries in Europe. 3G serveices are also going to be further applied in our country.
Mobile streaming media is a streaming media technology that been used on wireless network and mobile teminal. It provides streaming media services for mobile phones through 2.5G or 3G communication networks. It is result of combination of wireless telecommunicaions and multimedia telcommunications.
This paper analysiss the several key technologies of wireless streaming media transmission system. Including wireless streaming media transmission control protocol, wireless streaming media QOS control mechnism and software architecture of the system. And wireless streaming media transmission control protocol includes RTSP/SIP protocol,RTP/RTCP protocol; wireless streaming media QOS control mechanism is maily to research on several end-to-end adaptive control Algorithms based on RTP/RTCP,what's more, propose the Congestion Control Algorithm based on MSB burffer.
The main tasks of the paper:simplified implementation of embeded streaming protocol RTSP/SIP on mobile platform and improvement of RTP package.In order to real-time of video transmission and quality of video replay,design a congestion control module based on buffer and package loss process module on client:Buffer module change the buffer size dynamically to vary the video transmission delay and inform the internet state by communication with server;Package loss process module deal with those loss frame and incomplete frame avoiding jitter and Mosaic phenomenon. In the end, the paper analyses the design and implement of wireless streaming media transmission system, testing the system and analysing the test result.
引文
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