Research And Implementation On Quality Of Service Control For Streaming Media Base On Embed Client

With the rapid development of network and multimedia technologies,requirements for information diversity make network audio and video programs more and more indispensable. Thus Streaming media technology has emerged, used not only in the PC applications, but also widely in embedded equipment.Streaming media has some characteristics ,such as real-time transmission ,sensitive to transmission delay,large data volume and comlexity of computation. So, it seriously affects the streaming media's service quality ,which is packet loss, out-of-order, delay, jitters , and the resource limit of the embed client.To solve these problems,the embed client should implement some control strategies to ensure streaming media's quality.Based on the analysis of streaming media , we construct a client-based control model,to analysis the simplified calculating methods of these service parameters affecting streaming media,such as average speed, delay jitter, bit rate decoding. These parameters are used to improve estimates of the buffer zone's length.A series of control strategies are constructed to smooth the network transmission, save client resources,and ensure the quality of streaming media. These strategies include pseudo-order control strategies, disk caching strategies, zero-copy strategy initiative discarded strategy, a feedback mechanism. Pseudo disk caching strategies and tactics can take measures to avoid buffer overflow when the warning occurred;Zero-Copy good strategy takes the data transmission methods and the data structure design to avoid the copy Client CPU resources and thereby saving resources buffer; Strategy initiative can be discarded in a reasonable correlation between the use of data packet loss when connected to the other data packets discarded and thereby increase the effective utilization of the buffer zone; Feedback mechanism can send key performance parameters to the server, which adjusts the streaming media server transmission rate , so as to guarantee service quality streaming media.The client-based control model will be used in the IPTV system which is embedded watermark detection receiving end, and does the results of the analysis of the system's operation. Practice has proven that the model is indeed, and the introduction of the embedded system can ensure good quality of streaming media.