A multimedia teleconference system with adaptive synchronization

This paper reports work in the design and implementation of a multipoint multimedia conference system, with emphasis on adaptive synchronization algorithm. We have proposed an adaptive multimedia synchronization algorithm. The algorithm is adaptive to network changes, eliminates the need for a global clock, and is immune to the clock frequency drift, while its realization is very simple. The essence of the algorithm is partitioning the vicinity of the arrival epochs of multimedia objects into three regions and counting arrivals at each region. The synchronizer shifts the PlayBack Clock (PBC) according to individual counter contents. Synchronization algorithm proposed in this paper has been implemented within a teleconference system on Ethernet/FDDI using TCP/UDP. Experimental results show that the proposed synchronization algorithm performs well in our network testbed environment.