Research And Implementation Of Video Conferencing System Based On IP Network

As the information era proceeds,highly developed digital image processing technique and communication technique make multimedia communication possible,and it is now on the way of progress.Video conference have received more attention as an example of multimedia.In this paper we first describe the construction and characteristic of the video conference system and analyze the theory of protocol with ITU-T H.323 Recommendation which inculde video and audio codec standard, communication control protocol H.245.call signalling protocol H.225,as well as procedures within these protocols define how these components communicate.Also an experimental video conferencing system is designed and some relating key technologies are studied,which include multithread programming,transmission technology,MCU technology,Qos mechanism and so on.Especially, a video codec based on H.263 Recommendation with high fram rate as well as high compression ratio is researched and implemented because of importance of video application,which solves the bad image reconstrction quality problem existed in the most present video systems that adopt H.261 video compression algorithm.By using these technologies.a video conferencing system is implemented based on LAN.The system that the paper provides is easy to implement and the results of exmperiment is good .Such system can be widely used in the fields such as business conference,distance education etc. And it is of good practical value.