Effects of transmission delay in audiovisual communication

To provide audiovisual communication such as television telephone and television conference economically and efficiently, high efficiency coding, satellite communication and asynchronous transfer mode (ATM) are considered for introduction to the communication network. However, these technologies may degrade communication quality since they increase the signal propagation delay time. The effect of the propagation delay on the communication quality has been studied frequently for voice communication by telephone, but there have been few studies on audiovisual communication. Further, the effect on the delay quality by the addition of video to the voice has not sufficiently been understood.