Streaming Media Set To Grow Up The Research And Application Of Data Transmission Services

With the rapid envolution of the Internet, the streaming media application such as network radio station, video-on-demand, IPTV etc. becomes more and more popular. It needs a high quality performance serve. From compress encoding of the audio/video and the transport capabilities of streaming media server to the customer's playing quality, it makes streaming media involves many more computer technology to support. Streaming media which includes main key technique are: orienting to streaming transport of the video encoding expansibility, the system of streaming media server's structure, the peer to peer delivering technique of streaming media .This text aims at to streaming media server system structure based on general computer, studies two kinds of delivering service modes of the streaming media serve: the progressive streaming and the real-time streaming. Based on the OGG vorbis/theora audio/video coding, studied the organization process of the media streaming's data packets in the two kinds of delivering mode.The progressive streaming is a kind of concrete application of the traditional C/S network program frame based on the HTTP/TCP protocol. The media streaming data packets is presenting on file fomat with fixed-length in the period of delivering. The author regards: the progressive streaming is an expansion of a player read the native file and decode it. The difference is that the progressive streaming is just added a server as a middle link to deliver data packets, a source file can drive several foreign land players make use of simultaneity.The wrap fixed-length of the OGG page is the object that progressive streaming example– icecast serve to in chapter 2.Real-time streaming model appreanced is owing to the progressive development of streaming media application. It requires minor delays for the media data arrive at end-point, and can make use of the network bandwidth to add much more connection numbers of customer synchronized, also can adapt the network condition to adjust the sending rate smoothly. For these purpose, real-time streaming adopt a network programming frame which an interaction controlling protocol separated from the data carrier protocol. With the media streaming transporting, the media source incise the media data, form the RTP framing packet, which is the starting point in realizing the real-time streaming transport. In chapter3, present the process of OGG/Theora come into being the RTP framing packet. According to THEORA's character, design an algorithm of fixed-length RTP framing packets on the OGG Theora video code, and inplement a real-time streaming prototype server transporting RTP packets based on multicast. The testing results prove the algorithm is correct.By the high quality requirement of real-time streaming server, in charpter4, analyse the design and realize of Fenice, which is a real-time streaming server based on the OMS (open media streaming) platform, adopt RTSP/SDP/TCP protocol stacks as interaction controlling protocol, and adopt RTP/RTCP/UDP protocol stacks as data carrier protocol. The server read the framed RTP data packets from the source server, send to many connected players, and then make use of the received report returning from the players to adjust to the sending rate.