Based On The Hybrid P2p Network Application Level Multicast System With

With the rapid development of computer and network technology, more and more Real-time video stream application appear in the Internet, such as video phone, distance learning, video conference and so on. For this application, traditional IP multicast can not meet the requirements yet, application layer multicast technology (ALM) became the very essential of video stream technology. The advantage of ALM exists in its convenience to implementation, promotion, optimization for special application by changing the end system.The thesis mainly aims at researching an ALM algorithm and designing a real-time video application layer multicast system based on hybrid P2P network. According to the functionality, real-time video multicast system can be divided into the following four modules:video capture module, encoding module, transmission module and server module. The technology related to video capture module is already quite mature. Taking account of the convenience and simplicity of the development in Windows environment, we choose Video for Windows (VFW) platform. The server is responsible only for the management of the presence information of the member, which supplies support for the construction and maintaining of the application layer multicast tree. Contrarily, the transmission of the video is beyond of its responsibility. We build the multicast tree based on a degree-constrained algorithm in which we consider not only the bandwidth but also the computation ability of the member. Moreover, in order to improve the efficiency of multicast, multi-threading technology and the completion port model is also used. Because of the instability of ALM, we use H.263 standard for coding, which is an ITU-T draft standard. According to identity, the entire system consists of three parts:server, publisher and client. Server is composed of only server module while publisher includes video capture module, encoding module and the transmission module. And client is mainly made up of the transmission module and encoding module.From the result of the experiment, this algorithm and multicast system based on hybrid P2P network can carry out real-time video with lower controlled cost and lower time-relay, has a certain fault tolerance and reliability at the same time, it is a combination of the computer network technology and multimedia technology, which is quit practical.