ABSTRACT
Timecode was originally developed in order to clearly identify positional information on videotape in a manner similar to traditional motion-picture film. On film, this information is printed in human-readable form along the film edge, and the individual frames are clearly seen by inspecting the film. Videotape frames are recorded as magnetic imprints that cannot be seen by inspection, so when the timecode was introduced, it needed to contain details of the frames. The introduction of colour to the original monochrome signal increased the complexity of the video signal, so care had to be taken in joining non-contiguous sections during editing if disturbances in the picture were to be avoided. Developments in postproduction meant that the sound could be dealt with separately, as long as a guide video was provided, together with timecode. There have recently been great strides forward in the marriage between film and videotape for the purposes of post-production. This chapter explains the video and magnetic theory relevant to the recording and replay of timecode on video- and audiotape in order that the timecode processes described later may be easily understood.
