Video Conferencing Terminal Media Control Module Design And Analysis

The video conferencing system has been widely used in many fields because of its information pluralism and timeliness of response. It can put many multimedia information such as data, gaphic, image, audio, video and so on into a whole to people. In this thesis, the media control module in video conferencing system has been designed and implemented. It includes functions of capturing audio and video, displaying video at local computer, compressing, sending data, receiving data and displaying.In media control module, we use VFW(Video for Windows) library that is provided by Microsoft to capture and display video. VFW library can control and deal with video data that have been captured expediently. The function of audio capturing is implemented by adopting Waveform Audio API of Win32, because it is convenient for controlling. Screen capturing in media control module adopts DirectDraw module of DirectX software development kit. After testing and analyzing, it proved that using this method can expedite capturing screen and reduce the burden on CPU. The audio and video compression is implemented by using function interface of encoder and decoder. Sending data and receiving data are realized by using function interface of network sending and receiving module (medianet module).Through LAN test and analysis, the media control module in video conferencing system has many advantages, such as rapid capturing, continuously sending and receiving, smoothly showing and so on. Meanwhile, the module has a strong expansibility. It provides a good foundation for the development of follow-up and upgrade.