插件式短延时流媒体系统

【作者】 周俊；

【导师】 鲁东明； 邢卫；

【作者基本信息】 浙江大学 ， 计算机应用技术， 2006， 硕士

【摘要】 由于有线电视网在多媒体方面天然的优越性,以及技术进步和政策支持,各种数字化多媒体服务在有线电视网上快速发展。本人针对在有线电视网上开展视频会议服务进行了分析和研究,指出这种基于组播的实时会议系统面临的问题: 在实际应用中,根据不同的需求与采用的编码等技术方案的不同,要求流媒体服务系统有较高的灵活性与扩展性。 目前已有商用流媒体服务系统不适合实际应用的要求,需要自主开发流媒体服务系统。 视频会议服务有相当高的实时数据计算要求,又有延时性要求,从而需要一套严格的延时保证策略,在一定的硬件条件下,保证流媒体的质量的同时,保证流媒体的延时性。 针对上面这三个问题,本文做了以下几个方面的工作: 在深入分析了各种流媒体服务系统的需要和技术方案,总结它们之间的异同与关系的基础上,提出了一种基于插件的流媒体服务系统框架设计。在本框架下,将流媒体服务系统模块化,使其设计具有很高的灵活性和可扩展性。 在插件式框架设计下,编码实现了windows平台的插件式流媒体服务框架开发包。并解决了其中涉及的一系列性能等关键技术问题。 在插件式流媒体服务框架基础上,根据流媒体服务相关国际技术标准,开发了一套具有高度灵活性,适用于组播环境的流媒体服务原型系统。并以此验证了插件式框架的适用性。 之后,根据视频网络会议系统短延时性的要求,分析有线电视网络的特性,充分利用插件式框架灵活高效的特点,在对流媒体系统延时原因分析的基础上,提出了一系列短延时保证策略。 最后,针对短延时测试精度要求高的问题,提出了一套短延时系统模拟测试方案。对上述系统进行了测试分析,完成设计要求,并在CIF格式下达到VOIP推荐的短延时性要求。更多还原

【Abstract】 For the nature advantage in stream media application of CATV network, the technology progress and policy support, various digital media services has been deploy on digital CATV network. Base on the analysis of deploying video conference services on the digital CATV network, in this paper, we point out some challenges on developing such a broadcast based real-time video conference system:With too many difference requirements in practice and the rapid development of multimedia technologies, the media server should be fully flexible and expansible.Current commercial stream media system is not quite fit for the customized broadcast application requirement on CATV network. We need an independence stream media system.Under a limited hardware performance, the Real-time video conference services require both an acceptable media quality and low delay time. With the large real time media data processing, we need a strategy that can provide a strict low delay and support better media quality.In this paper, we proposed an integrated design and mechanism to solve these challenges.First, we analyze several typical Stream Media Servers, point out the commonness factors of there systems , propose and carry out a "module", "thread"," system" three level framework method of stream server, so that ,under such a framework ,the new media server can be much more flexible and expansible.Second, we introduce an independence, C/S mode, real time low delay stream server, which is a stream media real-time capture and multicast solution base on the plug-in framework.Third, base on the analysis of the cause of delay and difference stream characteristic, we propose an integrated strategy for low delay.Finally, we introduce a benchmark and evaluation method for this low delay media server. We do a full test on this server and measure up to the recommend low delay request of VOIP.更多还原