Abstract

Advances in computer and communication technologies have stimulated the integration of digital video and audio with computing, leading to the development of computer-assisted multimedia conferencing. We address the problem of media mixing which arises in tele-conferencing applications such as tele-orchestra. We present a mixing algorithm which minimizes the difference between generation times of the media packets that are being mixed together in the absence of globally synchronized clocks, but in the presence of jitter in communication delays on packet switched networks. The algorithm is shown to be complete: given that there are no other message exchangesexcept media data between mixersandmediasources,there cannot be any other algorithm that succeeds when our algorithm fails. Mixing can be accomplished by several different communication architectures. In order to support applications such as tele-orchestra, which involve a large number of participants, we propose hierarchical mixing a...

Citations