The Implementation Of Multimedia Dispatching Middleware In VCS

With the rapid development of computer network technology, video conference systems created on the IP-based network are widely adopted in many companies and organizations. Currently, there are three types of video conference system: Centralized VCS, Decentralized VCS and composite VCS. The system we developed is a typical centralized VCS, and can provide service in both unicast and multicast mode.Due to the special network environment and requirement of video conference system, the multimedia data dispatching module at the server side has a significant influence on the system performance. Based on the traditional producer/consumer model, this paper presents a new scheme and solution in dispatching the multimedia data at the server, and more, the analysis of other important factors that contributed to the system performance.The design and implementation of our network video conference system, especially the dispatching module was discussed in this paper. This module has a reliable performance with a relatively simple interface, can also be used by other AV applications as a groupware. This paper includes six chapters:In the first chapter, the knowlodge and the background of video conference system have been briefly introduced, including the history, constitution, class, related standard, key technology and future.In the second chapter, I introduced our Broadband Access Network System designed and developed by our lab, which is the foundation of our video conference system. Then two of the Mbone Tools-Vic and Rat, which are basic groupwares for our video conference system developing, have been introduced. And at last, the architecture of our system design was presented.Third chapter introduced the server design of VCS, that is, the general picture of MCU's architecture and design. The relations of these modules also were discussed at the end of this chapter.In the fourth chapter, we gave a detail discussion of some key technologies concerned within designing and implementing the MCU of VCS, including a newbuffer scheme, which formed the basic structure of our MCU; a packet-discarding scheme, which keep the multimedia data up to data; and the discussion of the selection of network data transmit method, and UDP hole punching technology. At last, multicast technology was discussed.After the discussion of some key technologies used in VCS, final chapter -the fifth chapter introduced the design and implementation of our multimedia-dispatching module. This chapter gives the reader a more detailed picture.And the last chapter is a general statement of the system and future work.