清华大学流媒体讲义_流媒体技术概述

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,五道口生活网,五道口论坛, 流媒体技术概述,五道口生活网,五道口论坛, （,Streaming Media,）,连续媒体（视频,/,音频）经压缩编码、数据打包后按照一定的时间间隔要求连续地发送给接收方设备，接收方设备在后续数据不断到达的同时对接收到的数据进行重组、解码和播放。,五道口生活网,五道口论坛, sensitive,End to end delay,Delay jitter,Loss tolerant,for traditional data:,loss intolerant but delay tolerant,五道口生活网,五道口论坛, stored audio and video,Streaming live audio and video,Real-time interactive audio and video,Classes of Streaming Media Applications,五道口生活网,五道口论坛, of Streaming Media Applications,五道口生活网,五道口论坛, of Streaming Media Applications,五道口生活网,五道口论坛, of Streaming Media Applications,五道口生活网,五道口论坛, of Streaming Media Applications,五道口生活网,五道口论坛, of Streaming Media Applications,五道口生活网,五道口论坛, 流媒体技术概述,五道口生活网,五道口论坛, System (,HHI,),EyeVision,(,CMU,),五道口生活网,五道口论坛, Server,、客户端软件,RealPlayer,组成，其流媒体文件包括,RealAudio,、,RealVideo,、,RealPresentation,、,RealFlash,，系统采用,SureStream,技术，自动持续调整数据流量适应实际应用的不同网络带宽需求。,五道口生活网,五道口论坛, Media,微软的,Windows Media Technology,目的是实现网络视音频等多媒体流信息的传输与播放，由,MediaTools,、,MediaServer,、,MediaPlayer,构成，其核心是,ASF,媒体格式，支持任意压缩,/,解压缩编码方式，并可以使用任何底层网络传输协议。工具集丰富以及捆绑在,WIN2000,中是,Windows Media Technology,的优势。,五道口生活网,五道口论坛, Media,五道口生活网,五道口论坛, Media,五道口生活网,五道口论坛, Media Intelligent Streaming,Multiple-Bit-Rate Encoding,Intelligent Bandwidth Control,bandwidth selecting,bandwidth switching,Rate shaping,Intelligent Image Processing,五道口生活网,五道口论坛, StreamingServer,、带编辑功能的播放器,QuickTime Player,、制作工具,QuickTime 4Pro,、图象浏览器,Picture Viewer,和,Web,插件,五道口生活网,五道口论坛, Time,Media Server:,多媒体服务器（系统图中为,MS,）,Media Cast,er,:,实时广播服务器（系统图中为,MC,）,Mp3 Server:MP3,音乐播放服务器,Streaming Player:,用户端播放软件,Media E-Mailer:,音频多媒体电子邮件软件,五道口生活网,五道口论坛, Time,五道口生活网,五道口论坛, 务 端 软 件,五道口生活网,五道口论坛, Content Manager),的重要一员，它与,IBM DB2 Digital Library,和管理多媒体内容的,IBM DB2 Universal Database for managing multimedia content,通用数据库紧密集成，用户可通过传统的浏览器如,IE,或,Netscape,观看视频。,Video Charger,支持基于最新标准的技术，可把多媒体内容组织到一体化的平台上，并支持点播，广播和实时压缩播放。,Oracle,公司的,OVS,Oracle,公司的视频服务器软件,OVS,可在包括网络计算机和机顶盒在内的系列平台上播放视频。同时还可以传送,MPEG2,、,AVI,格式视频及,WAV,音频数据流。,Oracle,在客户机一端的应用开发工具很强大，它提供全套,Java,系列和,Active X,控制工具，允许在播放环境下顺利进行集成。适合提供几百个以上的并行输出码流的大型流媒体传送系统。,五道口生活网,五道口论坛, IP,方案是端到端完整的网络视频解决方案。,Cisco IP,方案充分利用了微软的,Windows Media,技术。同时它与苹果公司的,QuickTime,客户端，,UNIX VIC,、,Netscape,插件结构兼容。,Sun,公司的,Sun StorEdge,Sun StorEdge,媒体中心视频服务器，是,SUN,公司新推出的视频服务平台。它建立在公开标准上，可以在低比特率通过因特网实时发送高质量视频流。服务器在,Solaris,上运行，能流任何标准的,RTP,形式。客户能使用苹果的,QuickTime,播放器或任何与,RTSP,兼容的播放器来观看流内容。,Macromedia Shockwave,能够方便地以流的方式在,Web,页面中加入图象、动画、交互界面等，实现边下载边播放。,五道口生活网,五道口论坛, Streaming Media Alliance (ISMA),http:/www.isma.tv,Apple,、,Cisco,、,Kasenna,、,Philips,和,Sun,五家公司发起在,2000,年,12,月成立,Internet,流媒体联盟，为开发,IP,端到端媒体流解决方案制定开放标准。,MPEG,标准工作组,中国数字音视频编码标准工作组 （,AVS,）,五道口生活网,五道口论坛, 流媒体技术概述,五道口生活网,五道口论坛, Video,Requirements,comfortable,visual quality,of service in terms of stringent playback continuity,demanding bandwidth,over fluctuant and heterogeneous networks,system stability,to high churn rate,scalability,for large growing community of users,Google Inc., which acquired online video-sharing site YouTube last year, said,the Internet was not designed for TV,. Googles head of TV technology said that the Webs infrastructureincluding that of Googledoesnt scale, and is not likely to offer the quality of service that consumers can expect.,五道口生活网,五道口论坛, Service,），不能严格保障视频播放所需要的传输服务质量（,Quality of Service,，简称,QoS,），因此，如何在,“,尽力服务,”,的网络传输条件下获得良好的视频播放质量成为了一个重大的挑战。,五道口生活网,五道口论坛, to support large scale Streaming,五道口生活网,五道口论坛, path,Access,SW,Domain A,Domain B,Access,SW,Source,Receiver,56 kb/s,R=56 kb/s,R56 kb/s,No bandwidth reservation,五道口生活网,五道口论坛, P2P be successful ?,delay, throughput, stability, security,奥运 酷,6,网,带宽有限，动态变化,五道口生活网,五道口论坛, of Delay,Sampling,Packetization,Transmission,Reception,Decompress,Synchronize,Display,Compress,五道口生活网,五道口论坛, path,Access,SW,Domain A,Domain B,Access,SW,Source,Receiver,56 kb/s,Delayed packets regarded as lost,Playback deadline,五道口生活网,五道口论坛, is jitter ?,Jitter: variation in delay,Can be measured as the variance of delay.,Sender,Reciever,五道口生活网,五道口论坛, do we care about jitter anyway?,Smoothness of playback.,What is the cost of a jitter buffer?,Increased end-to-end latency.,When will we care about this?,Interactive streams.,Live streams.,Stored playback applications can afford the cost of larger jitter buffers.,五道口生活网,五道口论坛, to ?,Error recovery,Error resilience,Other benefits of buffering,五道口生活网,五道口论坛, path,Access,SW,Domain A,Domain B,Access,SW,Source,Receiver,No packet loss,Loss of packets,No retransmission,五道口生活网,五道口论坛, Congestion Control,How to ?,五道口生活网,五道口论坛, Modem,、,ADSL,、,各子网段的传输负载的不同导致用户可用带宽的差异,用户端设备处理能力的差异,PC, STB, PDA,异构性,五道口生活网,五道口论坛, （表中带宽单位为,bps,）,Modem,ATM,LAN Ethernet,Wireless,1992,年,2.4K-9.6K,/,10M,/,1996,年,28.8K,600M,100M,9.6-19.2K,2000,年,56K,2.5G,100M-1G,384K(W3G),1M (WLAN),五道口生活网,五道口论坛, PC,900-1.2G,256-512,12801024,24-32,Midrange PC,650-800M,128-256,1024768,24-32,Laptop,650-750M,64-128,1024768,16-24,PDA,100-200M,8-32,300200,2-8,五道口生活网,五道口论坛, devices :,imited processing power,battery capacity,memory limit (not so important nowadays),small screen,􀂄,Wireless environment :,high error rate (retransmissions),limited bandwidth (access level),switching between base stations (mobility),五道口生活网,五道口论坛, networks have high loss rates,Roofnet,Objective:,High throughput despite lossy links,Avg. 30%,loss,五道口生活网,五道口论坛, Routing vs.,Opportunistic Routing,Best single path, loss prob. 50%,五道口生活网,五道口论坛, single path,loss prob. 50%,In opp. routing ExOR,05, any router that hears the packet can forward it,loss prob. 0.5,4,= 6%,Opportunistic routing promises large increase in throughput,src,R1,dst,R4,R2,R3,50%,0%,50%,0%,0%,0%,50%,50%,Fixed Routing vs.,Opportunistic Routing,五道口生活网,五道口论坛, 流媒体技术概述,五道口生活网,五道口论坛, to End),流媒体技术,流媒体系统技术,数字版权保护,流媒体关键技术,五道口生活网,五道口论坛, Server,Multimedia Server,Hybrid Proxy,Mobile Host,Mobile Host,Internet Client,Internet Client,智能终端,自主版权,Codec,多媒体流,协议族,可扩展,编码技术,流媒体组播,码率控制,算法,面向网络的自适应编码与传输,高效网络,子系统,磁盘调度,算法,媒体数据,分组存储策略,多媒体流,调度算法,兼容无线和,Internet,的流媒体代理服务器,流媒体服务器,五道口生活网,五道口论坛, Dapeng Wu Hou, Y.T. Wenwu Zhu Ya-Qin Zhang Peha, J.M, Streaming video over the Internet: approaches and directions, Circuits and Systems for Video Technology, IEEE Transactions on,2001, Volume: 11, Issue: 32,D. Wu, T. Hou, W. Zhu, H.-J. Lee, T. Chiang, Y.-Q. Zhang and H. J. Chao. On End-to-End Architecture for Transporting MPEG-4 Video over the Internet, IEEE Transactions on Circuits and Systems for Video Technology, vol. 10, no. 6, pp. 923-941, Sept. 2000.,3,T Nguyen and A zakhor. Distributed video streaming over Internet.,Multimedia Computing and Networking 2002, Multimedia Conference.,2002.,4 B. Carpenter and K. Nichols, Differentiated Services in the Internet, IEEE Proceedings, Vol 90, No. 9, 2002.,5 John G. Apostolopoulos, Wai- tian Tan, Susie J. Wee, Video Streaming: Concepts, Algorithms, and Systems, J. Conklin, G. S. Greenbaum, K. O. Lillevold, A. F. Lippman, and Y. A. Reznik, Video coding for streaming media delivery on the Internet,” IEEE Trans. Circuits Syst. Video Technol., vol. 11, Mar. 2001.,2,W. Li, Overview of fine granularity scalability in MPEG-4 video standard, IEEE Trans. Circuits Syst. Video Technol, vol. 11, no. 3, pp. 301-317, Mar. 2001.,3,Schwarz, H, Marpe, D, Wiegand, T,Overview of the Scalable Video Coding Extension of the H.264 AVC Standard,IEEE Trans. Circuits Syst. Video Technol, Volume 17, Issue 9, Sept. 2007 Page(s):1103 - 1120,五道口生活网,五道口论坛, TV),电视直播,Live Broadcasting,IPTV,五道口生活网,五道口论坛, involved ?,China Telecom, China CNC, ,SARFT, CCTV, ,Microsoft, IBM,UTstart, Siemens, ZTE, Huawei, ,What is behind ?,Streaming media,IPTV : one of the most hot word in China,五道口生活网,五道口论坛, Process,五道口生活网,五道口论坛, from other new applications,Multiview Video Streaming,Fast viewpoint switch,Random access,Bandwidth, ,Video sensor network,Traffic, Environment, Public Safety, ,Video blog,Blogcasting, Social Network Community,Whats the common requirement of them?,Huge video sources,Need to provide streaming service,both On-Demand and Live,Low resource in the source node,Challenge:,how to provide streaming services,with flexibility and QoS guarantee,IVVV System (,HHI,),EyeVision System(,CMU,),五道口生活网,五道口论坛, SHARP,五道口生活网,五道口论坛,