Monday, 15 September 2014

TIMECODE



This will enable every video frame that is recorded to be numbered which will represent hours, minutes, seconds and frame. This will allow precise identification of each frame when editing and the operator is usually the one to arrange the method of frame numbering that is going to be used.

Record run time code is a setting which allows you the choice between numbering each frame with a consecutive number each time the camera records. You can adjust the internal clock to suit the real time and day and when a recording will take place, the time at that particular point will re-code against the frame; this s either called free run recording or time of day recording.

There are typically two methods of recording:
  1. Longitudinal time code – This is recorded with a fixed head on a track reserved for time code. It can be decoded at normal playback speed and at fast forward or rewind but it can’t be read unless the tape is moving as there is no replayed signal to be recoded.
  2. Vertical interval time code – This is time-compressed to fit the duration of one TV line and recorded as a pseudo video signal on one of the unused lines between frames. This record as a variation in signal amplitude once per frame as binary digits; i.e. 0 = black and 1 = peak white. This is also recorded in pseudo TV signal and can be read in still mode which an editor may need.
DIGITAL TIMECODE
This allows time code to be stored as digital data in the sub code format of DVCPro and Digital-S. Since this is written in data, it can also be read in still mode even while editing. The sub code area of DVCPro track is used to record time code and user bit data.

CTL - CONTROL TRACK
Control track is a linear track recorded on the edge of the tape at frame frequency as a reference pulse for running speed of the replay VTR. This provides data for a frame counter which the camera’s LCD can display. It is helpful for editors to have the recorded cassette have a continuous control track and to reset to zero at the start of each tape.

When you select CTL, the time codes are a translation of the reference pulse into a convenient method of displaying tape elapsed. A main purpose of striping a tape for editing is to record a continuous control track. However, if a CTL is selected, in mid-cassette and the Reset button is depressed, the control track will reset to zero and will no longer indicate tape elapsed time.

The cause of headaches among editors used to be where a single tape had a break in the timecode resulting in multiple '0000000' points, which would confuse the editing system during logging. Nowadays, with most modern non-linear editing applications, timecode has become less of an issue and simply useful in locating a particular clip.

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