Research And Development Of The Real-Time Online Tutoring System Based On IP

The large information capacity of multimedia data and the limited transmission bandwidth make the compression code of the video/audio, the option of network protocol and the framework of stream media server the key technology in real-time tutoring system. This paper studies the realization of real-time online tutoring system based on IP in pure software environment for the purpose of adaptation to network condition, full utilization of network resource and better service in application layer. The final result proves to be quite successful.This paper introduces the MPEG-4/G.723.1 standard of video/audio coding and decoding, the real-time transmission protocol and IP multicast technology. It also studies the streaming media server of real-time tutoring system in its framework and design, method of service, system structure, the policy of managing disc buffer memory, the policy of admission control and stream scheduling and the server module of this system based on these policies through Visual C++ language. Based on the study, the system client has been designed and realized finally. The client uses buffer memory to remedy the delay of data, and further reduces the delay of transmission and play of the streaming media. Meanwhile, video/audio data gathered through VFW (video for windows) and audio function of understratum are transmitted by means of RTP/RTCP on UDP. The author designs the Dynamic-Link Library encapsulation of gathering and playback audio/audio data. Performance test shows that this system can meet the demand for omni-directional real-time teaching.