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ALSO SEE: GENLOCK; TIMEBASE; METADATA; DROP FRAME

  • Information recorded alongside the picture detailing the time (either real time or an arbitrary reference time) each frame is captured.
  • Takes the form hh:mm:ss:ff (Where ff is frames i.e 1 to 24 at 24fps for cinema).
  • Used in editing systems to allow frame accurate cutting points.TIMECODE is not the same as GENLOCK.

There are several systems of TC in use but most important for film and digital cinema use are the various SMPTE timecode standards found in most high end camera systems. The most commonly used system in digital cinema cameras is LTC – Longitudinal Time Code where timecode is recorded alongside the picture, effectively as an extra audio track.

The TIMEBASE for SMPTE LTC timecode can be 24, 25 or 30 fps and each frame records an 80 BIT code containing the time itself (as hh:mm:ss:ff) plus extra METADATA including “user bits” and flags for DROP-FRAME and other technical information.

The bit rate for LTC ranges from 1920Hz to 4800Hz depending on TIMEBASE and actual code recorded for each frame, a frequency range that when played as an audio track through a speaker gives a high pitched pulsing sound similar to that of old fashioned modems.

Timecode generators are never 100% accurate and where live action footage from multiple cameras needs to be cut together (and it is not practical to use a clapper board) cameras must be “jammed” or SYNC-ed to each other or to an external clock either continuously or at regular intervals to avoid the cameras’ internal clocks drifting too far apart from each other.

THIS PAGE IS A GOOD SUMMARY OF TIMECODE

ALSO SEE: GENLOCK; TIMEBASE; METADATA; DROP FRAME

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