Control track longitudinal timecode, or CTL timecode, developed by

JVC JVC (short for Japan Victor Company) is a Japanese brand owned by JVCKenwood corporation. Founded in 1927 as the Victor Talking Machine Company of Japan and later as , the company is best known for introducing Japan's first televisions and for ...

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 t ...

onto a videotape. Similar to the way

VITC Vertical Interval Timecode (VITC, pronounced "vitsee") is a form of SMPTE timecode encoded on one scan line in a video signal. These lines are typically inserted into the vertical blanking interval of the video signal. With one exception, VITC ...

timecode is embedded in the vertical interval area of a video signal, CTL timecode embeds SMPTE timecode in the ''

control track 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 pulses, each pulse corresponding to the beginning of each frame. This allows the video tape player t ...

'' area of

helical scan Helical scan is a method of recording high-frequency signals on magnetic tape. It is used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, and some computer tape drives. History Earl E Masterson from ...

video recordings. The advantage of both VITC and CTL timecode is that an audio track does not have to be sacrificed for

linear timecode Linear (or Longitudinal) Timecode (LTC) is an encoding of SMPTE timecode data in an audio signal, as defined in SMPTE 12M specification. The audio signal is commonly recorded on a VTR track or other storage media. The bits are encoded using the bi ...

. 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 , the common initialism for Super VHS, is an improved version of the VHS standard for consumer-level video recording. Victor Company of Japan introduced S-VHS in Japan in April 1987, with their JVC-branded HR-S7000 VCR, and in certain overse ...

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".

References

{{DEFAULTSORT:Ctl Timecode Timecodes

See also

References