Design Of Distance Teaching System Based On Direct Show Technology

Distance teaching is an important direction for the application of network multimedia technology. It breaks through the limitations of time and space, and provides greater convenience to the large number of learners. The distance teaching scheme realized with software will be the chief method in the future because of cheap cost, high scalability and flexibility.Steaming media is a sort of continuous media which adopts streaming technology to transmit. Using streaming media in distance teaching system, even under poorer network conditions, it will still provide clear and uninterrupted audio/video samples to users. Multicast solves the problem that a server sends media samples to the specific receivers. Compared to the way unicast and broadcast, multicast reduces network congestion and burden on server. So it is suitable for use in distance teaching systems. Video and audio files adopted MPEG-4 have high compression ratio and imaging quality. And they require low level hardware and software environment. So MPEG-4 is also a good choice for distance teaching system.DirectShow can deal with streaming media commendably. It supports a various format of media, facilitates media replaying, format changing, capturing and so on. Filter is the core component of DirectShow. So in distance teaching system used DirectShow technology, the design of filter and filter graph manager is the most important part. The topic adopted DirectShow technology to design filters needed. Combining with filters DirectShow provided, synchronous and asynchronous distance teaching systems were designed each. After the actual testing, the software programs were proved meeting the requirements.