Lip Sync. Error

Situation in motion pictures where picture and sound are not synchronized in time. So named because the error is particularly noticeable as subject lip movement that does not match the words spoken. For both film and videotape, the sound head is several inches away from the projector gate / video heads and careful adjustment is needed. Video processing units, such as line doublers that accumulate several frames of video in order to do their processing, can introduce lip sync. error.