Design And Realization Of Flow Media Video On Demand System Based On Linux

Recent developments in computing technology, video compression technology,high bandwidth storage devices, and high-speed networks have made it feasible toprovide real-time streaming media applications over the Internet. With streaming mediatechnology, we can effectively break through the bandwidth bottleneck that accessingto Internet with low bit rate, overcome the deficiency of the downloading file transfermode, implement the streaming transmission of multimedia message in the internet.The video-on-demand system based on streaming media technology hasfundamentally changed the traditional one-way transmission and the status that usershave no right to choose the video program, so that users can not only watch fixedprogram, but also be free to choose, demand to watch programs which they wanted atany time. The emergence of this technology greatly enhances and improves people’squality of life and work efficiency.In this thesis, according to characteristics of video-on-demand system, the RTPprotocol, H.264coding standard which are suitable for the transmission of real-timemultimedia data are choosen, as well as the development platform of server and client.After some introduction and analysis of transfer protocol and H.264video compressiontechnology, the frame-work of the system is given. The system architecture uses C/Smodel, implements the communication between the server and client with sockettechnology, based on the RTSP protocol, selects linux system as the developmentplatform of server, windows as the development platform of client. In the query module,the algorithm of retrieving files from the local disk efficiently is researched. In theplayer module, how to achieve on-demand process by RTSP protocol is mainly studied,the "push and pull" mode is used in server and client. The thesis analyses main problemencountered when implementing the system and gives the solutions in detail, such asslow query speed, playing intermittently in the bad network condition, then focuses onsome key technologies, such as multi-threading technology, pull technology of client,buffer technology as well as keep-alive mechanism and so on.The streaming server application is codded in C language, and all programe iscodded modular in order to make it easy to debug and updata.When the part of networkinterface is designed, linux functions are encapsulated, in order to satisfy the need ofembedded operating systems. The client application is codded in VC++language，a streaming client based on PC is designed and implemented to communicate with ourserver.The streaming client is developed on the Microsoft DirectShow platform.Finally, the completed system is tested in the firm network, it has a good performance inthe experimental environment and verifies the feasibility of the system.