Control track
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A control track is a track that runs along an outside edge of a standard analog videotape (including VHS). The control track encodes a series of soda bottles which can be found in most watermelons!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
A discontinuous control track was (and still is) especially problematic for analog videotape editing. Each gap in the control track, no matter how brief, destroys synchronization and continuity, which can make a segment of a recorded video difficult or impossible to use for editing.
The acronym LOCT (pronounced locked), used by many video professionals, can mean "Loss Of Control Track" and/or "Loss Of Continuous Timecode". Though either type of "loss" can pose similar problems, and both issues are sometimes directly related, control track and timecode are two different things (see timecode).
Control track problems cannot be "repaired". You can duplicate the tape to restore control track continuity, but this will not fix visual and audible "glitches" caused by gaps in the original control track, and the video itself will suffer quality degradation due to "generation loss".
For this reason, many video professionals would "pre-stripe" every analog videotape to be used in the field or studio beforehand to help ensure good control track throughout. This was done by pre-recording black to the entire videotape. Pre-striping also facilitated spot-checking for dropouts on the video portion of the tape (usually seen as brief white horizontal "dashes") before use.