Apple Final Cut Pro 7 - Manual (Page 1679)

Important: DV devices do not support insert editing because the tracks are too narrow
to be precisely replaced. DVCAM and DVCPRO formats support insert editing because
they use wider tracks.
About Tracks on Videotape
Most professional videotape formats have one video track, two or more audio tracks, a
timecode track, and a control track.
About the Control Track
Unlike the other tracks on a tape, the control track serves a purely practical function: to
make sure the tape plays at exactly the same speed it was recorded at so the signal is
output correctly. A control track is a series of electronic pulses on your videotape that
the VTR follows during playback, speeding up or slowing down the capstan (motor) as
necessary for consistent playback. These pulses are almost like electronic sprocket holes
that regulate videotape playback speed.
Insert editing allows you to replace individual video, audio, or even timecode tracks,
leaving the other tracks intact. The control track is never replaced during insert editing.
When you perform an insert edit, the VTR uses the control track to play back the tape at
the proper speed while recording new video or audio tracks.
When the control track is broken, you may see the video signal jump or look unstable for
a few seconds. This happens because the VTR relies on a consistent control track to control
the speed of the deck’s motor. A missing or inconsistent control track causes the motor
to change speed drastically, which means the video signal isn’t read at the proper speed
of the tape, and so the image is not scanned properly. Control track breaks may not always
be noticeable, but they are unacceptable in a professional environment.
About the Timecode Track
Timecode is also recorded onto a separate track on non-DV tape formats. Timecode allows
your computer to control your camcorder or deck and import or export frame-accurate
video clips. When you’re using the Print to Video command, abrupt breaks can cause
subtle gaps in the timecode track. Although these happen less often than control track
breaks, they can cause problems in a professional environment.
Requirements for Assemble or Insert Editing to Tape
Before you can edit to tape:
• Your video equipment must support either FireWire or serial RS-422 remote device
control.
• Your deck must support recording; you cannot perform edits on play-only decks.
• Your camcorder or deck must support insert editing, if you wish to do that type of
editing.
1679 Chapter 101 Assemble and Insert Editing Using Edit to Tape