流媒体播放器中网络子系统的设计与实现

【作者】 刘文红；

【导师】 刘心松；

【作者基本信息】 电子科技大学 ， 计算机系统结构， 2006， 硕士

【摘要】 当前政府正在大力推广Internet及宽带网络,加之正在兴起的网络电视计划,这些因素极大的推动了网络流媒体业务的迅速发展。针对目前流媒体应用最广泛的视频点播和在线直播服务, 8010实验室自主研发了具有高可靠性、高并发性、高性价比及高伸缩性的数字有机体流媒体播放系统。在流媒体播放系统中,流媒体播放器作为一个客户端应用软件与流媒体服务器、媒体源采集与存储转播系统技术并列成为其中最重要的三个组成部分。对流媒体播放器而言,网络子系统结构设计、流媒体相关协议栈的实现与媒体流同步设计又是其中重中之重,它们决定着流媒体播放器的播放质量与效果,因此文中着重对这些内容详细分析,总体而言包括以下几部分内容。研究并介绍了流媒体发展概况、流媒体的基本概念、技术概要、流媒体协议标准和流媒体通用编码格式MPEG-4编解码技术等。分析了流媒体播放器整体架构设计、网络子系统在播放器中的重要位置及其设计思路。阐述了网络子系统本身具体的设计实现,及其与流媒体播放器主控制模块之间的接口定义与实现。详细分析了流媒体相关协议在播放器网络子系统中的具体实现,包括RTSP、SDP和RTP/RTCP等,分析了每种协议实现时的主要数据结构、主要函数接口和报文解析过程等细节性描述。分析了流媒体同步的重要意义及在网络子系统中的具体实现,提出并实现了一种创新的同步机制。流媒体播放器网络子系统在设计中不仅实现了其应具有的主要功能,而且还针对8010实验室数字有机体平台独有特点作了针对性研发,使之能够充分利用数字有机体系统的相关特点。比如,播放器能利用数字有机体系统的故障重构功能,当正在提供服务的后台服务器出现故障时,能自动被其他服务器接管,从而能够从断点处继续播放,即客户端的播放不会受到后台服务器故障的影响。文中最后一部分分析了网络播放时相关的传输性能及系统测试等。更多还原

【Abstract】 With the popularization of the Internet and broadband network supported by the current government and the rapid growth of the IPTV (television over IP) plan , the stream media service over network develops fast too. In order to supply the main two services–VOD (video on demand) and IPTV which are used popularly in the application, 8010R&D designed a new streaming media system based on our new operating system named Digital Organic System (DOS) with high dependability, high concurrence, low-price-high-efficiency and high retractility as its characters .In our stream media system , there are three important components. streaming media player used as an client software, stream media server , the storing and transmitting technology used in the system . As for our media player, the most important parts are three aspects. the design of the net-subsystem, the accomplish of the protocol stack and the design of streaming medias synchronization mechanism.These parts are so important that can influence the quality of our media player’s work, so I go into details these parts in this paper , the main content is below.Firstly, this thesis briefly introduces the streaming media development trend, the basic concepts in this area including the basic important technologies and the stream media protocols standards. After that, this thesis introduces the Edcode (encode&decode) technologies such as MPEG-4.Secondly, after analyses the design of the main frame of the whole player and the importance of the net-subsystem in the player, this thesis pays more attention on the accomplishment of the idea. Then, this thesis describes the design details of the net-subsystem in the player. Those details include the interfaces between the main control module and the subsystem.Thirdly, this thesis emphasizes the application details about the implementation of the protocols such as RTSP,SDP,RTP&RTCP,including the major data structures , function interfaces and the details of the process of the analyzing Datagram .更多还原