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SIP (Session Initiation Protocol) protocol , as a next-generation network softswitch application-layer control signaling protocol , session management , including audio , video , data and multimedia communications to provide good support with a wide range of application prospects . VOD (Video on Demand) is the hot issue of the field of multimedia , VOD system, because of its the autonomy of on-demand , multimedia manifestations intuitive , and has been widespread concern in the market . The system is to meet this need a signaling protocol . This paper focuses on the SIP - based VOD system launched . This paper studies the the VOD system technology on SIP , streaming technology, streaming media protocol RTSP protocol for careful analysis and research ; study the features of the SIP protocol , the network structure and the application of the principle , a brief analysis of the mechanism of its message . Secondly, the overall design of the SIP-based VOD system , based on SIP and RTSP protocol associated with the similarities and differences , the two designs , ie SIP combined the RTSP programs and S-VOD ( extended SIP) program , two programs focused on the research , analyzed their advantages and disadvantages , according to the S-VOD program has advantages and prospects , select the program to research and design . For the difficulty of the S-VOD program , namely the lack of VCR functionality , key design . The design idea is based on the SIP protocol has good scalability characteristics , to define a new method to achieve the VCR functions , that is, play, pause , fast forward and rewind . On this basis , the design of the S - VOD system network architecture , and describe its on-demand process . Then, the design to be functional realization . Including the use of open source the server openSER build SIP network server , use oSIP protocol stack development client and SIP module , and focus to achieve the various functions of the VCR . Finally, the S-VOD system testing , test data with existing VOD system comparison and analysis , the results show that the S - VOD system performance is excellent and has great application value .
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