A method and apparatus to insert variable audio delay during video
conferencing to achieve conflicting goals of lip-sync and interactive
conversation. The amount of audio delay is variable according to the
condition of the videoconferencing: long audio delay is inserted to
achieve lip-sync between audio and video playback during monologue
speech, but minimum or no audio delay is inserted during interactive
discussion or argument. Variable audio playback speeds may be used
instead of inserting quantum delay to achieve the same result. Various
methods and apparatuses to detect the non-interactive mode or interactive
modes are also disclosed.