连续媒体流的理论模型及缓冲对策研究

RESEARCHES ON THEORETICAL MODEL AND BUFFER MANAGEMENT OF CONTINUOUS MEDIA STREAMS

视频点播服务（ＶＯＤ）是当前交互式多媒体ＩＭＭ应用中的热门方向，而视频流的缓冲、控制策略是视频服务技术研究中相当关键的环节．本文试图采用全局的观点，利用恰当的数学工具建立了在网络并行下的请求流工作模型，并结合缓冲机制得到了一些关于媒体流服务的重要结论．同时，结合媒体服务的工作序列，给出了一些优化流控和数据缓冲的方法和策略．最后通过试验验证了该理论模型和结论的可行性．

It is the VOD (Video on Demand) that the most great demand field in the current interactive multimedia application. Furthermore, the buffer and control strategy of video streams are the corresponding key link in the researches of the video service technologies. Because the conventional strategies that are based on the events are unable to fit in with these strongly temporal video data, people need to do a lot of researches in all directions. In this paper, the authors try to use the global viewpoint, build a theoretical model that describes the working procedure of the request streams by the appropriate mathematics tools. Based on this model, the influence of the buffer mechanisms on continuous media streams are analyzed, and some important conclusions about the media stream service are given. Furthermore, according to the concrete working sequence of media service, some methods and strategies of optimizing stream control and data buffer are offered. At last, the practicability of the theoretical model and the performance of the multiple buffer mechanisms through a serial of tests are confirmed.