Synchronizing voice and video transmitted over separate channels

摘要

Reproduction of voice signals and video signals in a video telephony call are synchronized at the receiving end. Voice signals are transmitted from a first telephone device of a first party to a second telephone device of a second party via a public switched telephone network (PSTN) connection. The video signals are transmitted from a first computer of the first party to a second computer of the second party via packets in a computer data network. The video signals comprise successive video frames. A video latency time is determined for transmission of the video signals over the computer data network. If the video latency time is in a first predetermined range then transmission of the voice signals is delayed from the first telephone device to the second telephone device by a selected delay in response to the video latency time. The selected delay is no greater than a predetermined maximum voice delay.