The Research And Implement Of Video On Demand

The article introduces the basic conception of the VOD system,and the multimedia digital compression and decompression technology,and the stream-media technology,and detailedly anatomy what the VOD covers by the "PL VOD" system partly developed by myself.The VOD technology has developed since 90's in foreign. Now there are experimental VOD systems in some cities of China. The VOD system is a network system including hardware and software. The VOD software transmits multi-path,concurrent video data-stream real time from video server to client. It may offer interoperability to user in some degree. The VOD is rapidly developing with computer technology (especially digital compression and decompression of multimedia) network communication technology(especially stream media) and TV technology.In some meaning,the VOD is a revolution in video technology field,the huge potential market makes the main developed country throw into much money to develop and improve the VOD system.As the same time the software researchers all over the world throw a emphasis on it.The function of the VOD technology goes beyond people's imagine.At home people can watch program they like,search information go shopping,go hospital educate on TV,transfer Email,tour manual,ticket reserve,stock business and so on. The appear of the VOD technology enhances and improves people' s life level and work efficiency.The PL VOD System is developed by VC6.0 using object-oriented method,which provides a solution for being video on demand MPEG-1 file any time any where in LAN and WAN.It supports to be video on Demand any MPEG-1 file,video file's category,VCR function and all web browse.It applys the double-buffer technology,the data-pulled technology,the MPEG-1 decode technology,the media-playback technology based on DirectShow COM,and puts to use RTP/RTCP protocol. The double-buffer technology saves memory resource,enhances memory efficiency;the data-pulled technology improves the server's efficiency and performance,guarantees the video file to playback smoothly;MPEG-1 ensures the system's usability and feasibility;DirectShow ensures the audio and video playback correctly;the RTP/RTCP deals better with the system's real time.The PL VOD system works normally on all sorts of MPEG-1 streams. The system compares favorably with the same kind product of country in function.