嵌入式系统中流媒体服务质量研究

Research on Stream Media QoS of Embedded System

围绕网络流媒体技术以及嵌入式环境的特点,为保障流媒体的服务质量,研究了基于客户端的缓冲区控制策略,以及具有流量控制机制的流媒体网络通信技术。在探讨嵌入式视频点播系统架构基础上,提出了利用平均传输速率、时延抖动、解码速率和辅助系数这四个参数进行网络缓冲区长度估算的简化算法;并提出在客户端按照数据的重要性或优先级的不同来实施主动抛弃策略;该系统也针对服务器端引入了流量控制算法。结果表明,应用上述策略明显节约了缓存,并且实现了流量控制功能,改善了系统的服务质量(Quality of Service,QoS)。

Based on the features of both the network stream media technology and the embedded system,in order to ensure the QoS（Quality of Service） of stream media,the dissertation has shown a research work on the buffer control strategies based on the client and the stream media communication technology with flow control functions.Based on discussing the structure of VOD（Video on Demand）,a simplified method for estimating buffer length was proposed by using mean transmission rate,delay jitter,decoding rate and assistant parameter.The buffer control strategy of initiative discard at the client end was also given according to data＇s levels of priority.And a flow control algorithm was also provided based on the server end.The result indicated that buffer resources was saved,the flow control function was realized,and the sytem QoS had ben enhanced.