CTL Timecode
   HOME

TheInfoList



OR:

Control track longitudinal timecode, or CTL timecode, developed by JVC in the early 1990s, is a unique technique for embedding, or ''striping'', reference
SMPTE timecode SMPTE timecode ( or ) is a set of cooperating standards to label individual frames of video or film with a timecode. The system is defined by the Society of Motion Picture and Television Engineers in the SMPTE 12M specification. SMPTE revised ...
onto a videotape. Similar to the way VITC timecode is embedded in the vertical interval area of a video signal, CTL timecode embeds SMPTE timecode in the '' control track'' area of
helical scan Helical scan is a method of recording high-frequency signals on magnetic tape, used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, and some computer tape drives. With this technique, magnetic tape he ...
video recordings. The advantage of both VITC and CTL timecode is that an audio track does not have to be sacrificed for linear timecode. Though a very effective technology, and still probably in limited use today, CTL timecode never really caught on. JVC is apparently the only manufacturer that included CTL timecode capability in their video products, and this was limited to select professional
S-VHS S-VHS, the common initialism for Super VHS, is an analog video cassette format introduced by JVC in 1987 as an improved version of the VHS (Video Home System) format. S-VHS improved image quality by increasing the bandwidth of the luminance ...
equipment. When it was introduced, there was much negativity about CTL timecode, because people misunderstood how it worked. Many incorrectly assumed that CTL timecode was nothing more than a ''control track pulse'' signal. Control Track Pulse: Most are familiar with the digital "counters" on VHS recorders and camcorders, viewed via the onscreen display (OSD) and/or a dedicated LED display. These numbers are sometimes in real-time format (hours:minutes:seconds), but are often only an ambiguous 4 digit sequential counter. These numbers advance up or down based on the machine counting a tape's control track pulses. This type of display is useful only as a simple and temporary reference, as it is very inaccurate, and the counter is reset to zero when a tape is inserted. A basic 4 digit counter is almost completely worthless, as their rate of advance was never standardized by manufacturers. Conversely, CTL timecode is an ''absolute'' timecode with specific digital references for every frame of video. Thus, a tape with CTL timecode can always display current timecode position accurately, even if the tape is moved from one machine to another. CTL timecode embedding can be transferred when making a copy, as long as the recording machine supports CTL timecode. Because CTL timecode ''is'' SMPTE timecode, its timecode can be interchanged with other SMPTE timecode schemes, like VITC and LTC (linear, audio track) timecode, as well as SMPTE timecode devices like timecode readers, generators, window dub inserters, MIDI synchronizers, and edit controllers. CTL timecode is vulnerable to any gaps or problems in a tape's control track, but so is LTC and VITC timecode. The acronym ''LOCT'' (pronounced ''locked''), used by many video professionals, can mean "Loss of Control Track", and/or "Loss of Continuous Timecode".


See also

* AES-EBU embedded timecode * Burnt-in timecode *
MIDI timecode MIDI time code (MTC) embeds the same timing information as standard SMPTE timecode as a series of small 'quarter-frame' MIDI messages. There is no provision for the user bits in the standard MIDI time code messages, and SysEx messages are use ...
* Rewritable consumer timecode


References

{{DEFAULTSORT:Ctl Timecode Timecodes