On multipoint control units for videoconferencing

This paper examines the issues involved in the design of conference servers that support multiparty, multimedia conferences. These servers, called multipoint control units (MCUs) in the telephony world, coordinate the distribution of audio, video, and data streams amongst the multiple participants in a videoconference. The MCU is responsible for the processing of video and audio so that a conference participant can hear and see one or more of the other participants in the conference. It is also responsible for handling and forwarding the data streams from the participants. This paper presents different approaches to the design of an MCU to implement these functions. It also describes the design of a related device-a transcoding gateway that enables conferencing between participants using different video/audio equipment