| In the recent years, the rapid progress in digital video and network technologies has led to the rise of a series of multimedia streaming applications based on VoD (Video-on-Demand). Video on demand technology is developed along with the development of computer technology and network communication, which is synthesis of computer, communication and television technology. It takes most advantage of network and video technology, which totally modifies the passive style of receiving TV program and realizes video received on demand and play on will, which is synthesis of image, static image, sound, words and serves people with real-time, interactive and on demand service. VoD system requires transporting through limited bandwidth with individual QoS for each client. In this situation, the flow control scheme must be adopted, which can avoid the network operating towards congestion and maximize the efficiency of network bandwidth usage. So the study of flow control for video on demand system becomes an important issue.In this paper the study of flow control for video on demand system is mainly based on the widely used client/server model. On the base of research on congestion control, a flow control mechanism in video on demand system is proposed by introducing client buffer analysis. The clients detect the client buffer and evaluate the sending rate according to the network congestion state, and then send them back to the server. The video server considers the processing power of the clients on the basis of the consideration of the network congestion, and weights the evaluation rates according to the clients'buffer state, carries on resource scheduling, realizes multi-client balance, makes a better distribution of the network bandwidth according to the clients'demand. In this mechanism congestion control and client buffer control are combined to adjust the sending rate adaptively. This mechanism can meet the client requirement better and increase the network bandwidth utilization. |
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