Design And Implementation Of Application Level Multicast System For Video Stream

Real-time video stream technology, such as video phone, distance learning and video conference, plays an important role in all aspects of our life in the future. Besides, application layer multicast technology (ALM) is 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.This thesis introduces the features and development status of the P2P technology and the application layer multicast technology, analysises the two factors of the multicast tree structure,the node degree and the height of the multicast tree implementates an algorithm of degree-constrained application layer multicast construction,which comprehensively considers the network bandwidth and computing power of the nodesBased on the algorithm,We analysise the system requirements of the real-time video multicast system,which uses the hybrid P2P network structure.The system is divided into server, client and publishing client. And the functions is divided into the video capture function module, data compression decompression module, data transfer module and the P2P network control module. Video capture module uses the Vedio For Windows to implemente, and data compression and decompression module is applied by H.263 video compression standard.Data transfer module and the P2P network control module is the focus of this thesis,We choose the TCP protocol to transmit the participants information.The UDP protocol is used to transmit real-time video information. The system uses the Windows Sockets API to apply the network transmission. We design and implement an overlaped I/O which uses the completion port model and the three-thread model. P2P network control module is mainly applied in the degree constraint-based application layer multicast algorithm.We design and implement the real-time video streaming multicast system, meets the basic requirements of video conferencing on the Internet, The system is practical and the proposed degree-constrained multicast algorithm has be advanced.