Control track

Control track is a track along standard analog video tapes (including VHS), that encodes a series of pulses, each pulse corresponding to the beginning of each frame. This allows the video tape player to synchronize it's scan speed and tape speed to the speed of the recording. Thus, the recorded control track defines the speed of playback (e.g. SP, LP, EP, etc), and it is also what drives the relative counter clock that most VCR's have. A dropout in control track is usually a major flaw in a piece of recorded video, as the player usually loses tracking as soon as the track drops out. This usually leads to a gap in video and audio (since theres no information as to what speed the media is recorded at), the VCR's counter will freeze, and upon reaquiring the control track, the video will synch roll.