The Research On Media Center Streaming Protocols And Embedded Application

The purpose of the research of streamed media protocols is the promulgation format, which greatly affects the efficiency and quality of media transmission. This thesis gives in-depth research on the protocols as well as the principles of streamed media and optimizes the protocols pertinently. The research result has been applied to an embedded system and implemented the VOD system successfully.Firstly, this thesis explains the principle, way of transmission and structure of protocol stack as well as implementation optimization in details. In one aspect from the point of buffer management algorithm, adopting the frame based buffer structure instead of packet based and put forward some buffer management algorithm to guarantee the non-overlap of the key frames. In another aspect, multiplex technology is used to enhance the efficiency of receiving data. Moreover, system architecture of the whole Media Center is described. What's more, the application and implementation of real-time streaming protocol in VOD subsystem in Media Center is investigated, which includes the implementation of real-time streaming protocol stack, mpeg4 video decoder, AAC audio decoder and synchronize of video and audio. Finally, network characteristic and precision of data received are presented and analyzed. This thesis use the platform of Internet/Intranet, a DM642 processor of TI Company, a display device of TV set and other peripheral equipments. It is a kind of family electronic terminal of high integration, capable to access IP network and high intelligence, including VOD, local video playing back, receiving and sending emails, browsing web page and linking network. Finally the result shows that the protocol stack can run stable under the embedded environment, and it can accomplish MPEG-4 video with CIF format successfully, therefore it satisfies the system requirement.