Pull Strategy-Based All-format-supported VOD System And The System Performance Evaluation

By the rapid development of Internet and stream media technology ,all-format-supported VOD system become the emphases mode of service.The thesis first introduces the research background and development nowadays,then it discusses the criterion of performance evaluation of stream media server based on stream media technology and stream media server nowadays,and it puts forward the criterion of this research.Afterwards, the thesis analyzes the working principle of stream media server. A solution is presented. It consists of Web servers and self-developed clients. We use HTTP as transfer protocol, based on the transfer by blocks pull strategy. Then we describe the technology of play it through HTTP and build a client. The results show that we make HTTP and Web servers suitable for media streaming on Intranets and Internet.)At last ,in the processing of designing all-format-supported VOD system, we need evaluate the performance of the VOD system continually for the betterment of our system. The traditional method is constructing large-scale pressurre evaluation circumstance being made up of hundreds clients, but the evaluation circumstance is complex and the cost is high. The thesis brings forward a "pseudo decoding-based" performance evaluation method,the purpose is to release the cost and to achieve the evaluative effect of large-scale pressure evaluation with a few clients . Experiments show that the syestem of test can simulate the same network behavior as the real clients. It is apparent that this method is efficient.