P2p-based Video Conferencing System Architecture

Video conferencing system is a communication system of transmission the moving picture sequence, audio and data of many participants via network. With the quick development of network communication and video codec technologies, video conferencing system is applied abroad in many fields now, such as economy, science study and culture etc.Although the bandwidth is trending to gradual increase for the improvement of technology, it is not enough to provide satisfied quality of services at the present time yet. Usually, bandwidth needed by transmission of multimedia data, especially video, is exceeding the throughput of network providing. Video frame will be dropped when the network experiences congestion. The performance of data transmission may therefore be affected seriously. How to improve the quality of service for multimedia data on condition of bandwidth limit is the hotspot of research in multimedia application field recently.The existing video conferencing systems accord with H. 323 standard usually. They need one or more servers. The more participants, The more data servers must dispose and transmit. The quality of video received by participants declines rapidly. The servers become the bottleneck of extending system scale.Peer-to-Peer(namely P2P)technology is a hotspot in computer network technologies studying field at home and abroad at present. Client can link with other clients and exchange information directly without server. This paper analyzes the studying status at home and abroad, level and application foreground of video conferencing system. Aiming at the problems of existing video conferencing systems and combining P2P technology, this paper proposes a new architecture based on P2P. The new system has no server. The tasks, which were belong to servers before, are performed by participants now. It uses multicast technology in information transmission. It eliminates system's bottleneck, reduces the network congestion dramatically and increases the quality of video.JXTA technology provides a united platform for all kinds of P2P application. Compared with other P2P technologies, JXTA has the characteristics of operating each other, striding platforms and general use. The new video conferencing system in this paper is implemented on the JXTA platform.Video conferencing system can not ensure the quality of video very good because of the network bandwidth's difference and state's instability. In order to increase the quality, this paper analyzes and improves the vital technologies of audio and video codec, synchronization of audio and video streams, adapting bandwidth automatically in transmission and multicast etc.