文档介绍：华中科技大学
硕士学位论文
嵌入式P2P实时流媒体分发机制的设计与实现
姓名:万佳
申请学位级别:硕士
专业:通信与信息系统
指导教师:杜旭
20090522
华中科技大学硕士学位论文
摘要
基于客户端/服务器模式的嵌入式流媒体分发系统中,当大规模客户端同时在线
时,由于受 ADSL 上行带宽限制,家庭用户分发的媒体数据不能满足大规模用户观
看媒体节目的需求。传统嵌入式流媒体分发技术已经成为制约高效利用网络资源的
瓶颈。亟需一种能支持大量家庭用户同时观看节目的流媒体分发方式,在嵌入式机
顶盒上应用 P2P 流媒体分发技术成为必需。P2P 技术实现了对等通信机制,它引导
网络计算模式从集中式向分散式偏移,充分整合了互联网的潜在资源,提高了网络
利用率,有效地消除了传统技术所带来的瓶颈,因而具有广阔的应用前景。
本文对当前流媒体系统采用的 P2P 网络结构以及典型的 P2P 网状结构模型
CoolStreaming 中各模块的设计原理进行了详细的分析。在该模型的基础之上,针对
硬件基础和应用需求,提出了一种适用于嵌入式机顶盒设备的 P2P 流媒体分发机制,
包括:协议消息交换机制、媒体数据编解码、媒体块缓存策略和数据调度算法等实
时性保障策略。随后完成了此机制中的两个在嵌入式系统上运行的重要实体:采集
节点和一般节点的软件设计方案及具体实现。经过初步的系统测试以及结果分析,
验证了该分发机制的可行性,符合了应用需求。由于时间所限,该系统功能并不全
面,仍需要做进一步的研究和开发。
关键词:嵌入式; 流媒体; P2P; 调度算法; 缓存策略
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华中科技大学硕士学位论文
Abstract
Currently media streaming delivery systems are generally based on the client/server
mode in which home users sharing media programs is bounded with the ADSL upstream
bandwidth when the client scale is large, server-side bottleneck limits the expansibility of
systems that is very important to meet the need of large scale users. P2P media streaming
delivery technology shall be brought forward so as to solve the above bottleneck. By
leveraging media resource of available scattered normal peers, P2P technology changes
the way of peers’ communication and improves work utilization and es a
new trend in the future development.
The pares the frameworks of P2P technology and introduces the design
principle of ponents in the typical work model CoolStreaming. Based on
the embedded hardware and application requirements, a new P2P media streaming
delivery mechanism for embedded set-top box is designed where embedded capture peer
and normal peer are two important entities. Then the thesis introduces the transport
solution for the two peers, which emphasizes real-time assurance mechanisms including
protocol message switching mechanism, media encoding and decoding, media data-
caching and data scheduling algorithm. Finally, it validate