Research On Caching Replacement Scheme For Streaming Media System Based On Dynamic Fragment

The streaming media system is widely used in practice. However, a great deal of graphic data has many problems about slow system response, serious network congestion, low cache utilization in the network transmission. Especially, the hardware bandwidth is not quite ideal. For example, lack of ability to server network card to read and write,the low PCI clock frequency, width of bus less than64bit and so on. In this paper, a cache replacement scheme based on the expected value to future usage is proposed.And Stream conversion is realized by changing the way of segmentation based on Fibonacci sequence division.This paper consists of three main parts:Firstly, this paper starts from the key of streaming media. Under condition of different transmission protocols and different coding methods,it analyzes the importance of scheduling scheme in streaming media application through testing the average number of received segment and average download time. This paper assesses rationality of C/S pattern structure as an experimental platform of cache replacement scheme. This paper also describes the importance of fragment of static algorithm in whole scheduling scheme. Besides, the paper introduces the importance of cache replacement scheme and its importance on VOD system.Secondly, This paper proposes a new fragment which bases on Fibonacci for ULH algorithm achieve in cache replacement scheme. And through Ns2software simulates network environment and new fragment. In simulation, this paper analyzes that new algorithm has good effect on both reducing utilization of resource and depressing delay. From both vedio on demand and user behavior feature, this paper proposes a new cache replacement scheme based on the expected value of future usage.Thirdly, Specializing the ULH algorithm, the paper also records method such as modifying C++coding in Ns2, expanding the function module, and adding derived class from TclObject in the compiled hierarchy. Through establishing dumbbell network structure, Ns2simulator test delay of server response, delay of client request,delay of the target node, the network throughput respectively, which gets that ULH algorithm is superior to traditional LRU algorithm and LFU algorithm. Finally, through embedded the whole scheme in real network,testing streaming media player effect, then the preferable experiment effect is obtained.