Experience with implementation of multi-party video-conferencing application over packet networks

The increased speed of workstations and networks have made interactive multimedia communications between workstations across packet-switched networks possible. Transmission of real-time multimedia data over such networks has its limitations and problems. The basic problem pertaining to transmission of audio is synchronization whereas video coding is the main problem for video transmission. Application level framing (ALF) and the real-time transport protocol (RTP) provide a well defined framework for real-time multimedia communication over packet-switched networks. We develop a multi-party video-conferencing application, called VidZ, based on the “composable tools” approach which is extendable and provides for re-usability of the tools. We provide an overview of the issues involved in transmission of real-time audio and video over packet-switched networks, and relate our experience in the implementation of such an application