Research Of Multimedia Information Transmission In Net Classroom Based On Campus Network

Remote Education is considered as the most important method to build continual education.life education and diathesis education .It's the most important measure of the plan of Build Up Education Action in 21th century .So more and more countries have paid attention to this field. Although there are many formats to implement Remote Education, Net Classroom has become the most effective method because of its real time capability, vitality, and interactive capability.In this thesis, we analysed the characteristic of multimedia information in net classroom, and implemented a Net Classroom Software based on Windows98/NT OS and the campus network of DLMU. In the multimedia data transmission part of this project, we take different transmission methods according to the characteristics of different multimedia information to deal with the multimedia data transmission .For the graph information , we take the method based on semantics. And the image information was disposed with JPEG arithmetic method to compress the data on the server, decompress the data to display it on the client .To video and audio data ,we take the method of Microsoft DirectX .In the part of transmission control ,we implemented the transmission of multimedia data by IP-Multicast method and UDP protocol .Moreover to assure the integrality and synchronization of the multimedia data, we designed and implemented application layer transfer control protocol above the connectionless lower network protocol. Further more we build the control command channel based on TCP protocol to assure the credibility transmission of the control command and approve the transmission performance of multimedia data .The education functions of this project include screen image broadcasting, electron roll calling, electron raising hands, net cinema, file transmission etc .In order to increase the interactive function, the Net-classroom Teaching Control Protocol (NTCP) was extended by locking, unlocking ,remote shutting down and remote restarting etc.