Study On The Video Conference System Based On SIP Protocol

With the economic and culture development in human society, in order to meet people's ever growing material and cultural needs, and the higher requirements of computer network and the related technologies, the multimedia communication such as data, image and speech processing appears. In this situation, VOIP technology has developed by leaps and bounds, making use of the Voice Over IP and Video Over IP to integrate the IP-based and circuit-switched communication networks. Due to the advantages of easy and convenience, the video conference system has been applied to more and more files, whose value has also been recognized by more and more people.The current VOIP standard mainly includes the H.323 protocol implemented by ITU which is usually as the basic standard of the existing video conference system owing to its long time research and more mature development, and the SIP protocol published by IETF, respectively. However, since the SIP protocol was proposed by IETF in 1999, the merits of simple, open, compatibility as well as the scalability have helped the SIP protocol to make a rapid improvement. Comparing with the complex and ossification of H.323, the SIP protocol has better performance and distinct advantages in temporary, emergency and bulk meetings. Hence, the research of video conference system based on the SIP protocol has a great value.In this paper, based on the analysis of the SIP protocol and practical requirements on the highway local applications of video conference system, the system propose a kind of SIP-protocol-based video conference system. Five modules including Node Management, Conference Control, Multilevel Management, Audio Research and Signal Process are analyzed and each module is given a detailed workflow. In addition, the system also researches the following four key technologies: groupcast, RTP/RTCP, audio and video process, and address the theoretical analysis and application design.Finally, according to the above research processes we construct the experiment environment to test the performance of the system. The experiment result shows that the system reaches to the design goals and expected requests, regardless of the case of point-to-point video speech and multi-point video conference.