Appendix 1

The Filmmaker’s Guide to Final Cut Pro Workfl ow
represents. Keep in mind that the time code has no effect on the actual frame rate, nor are any frames
skipped or dropped. Only numbers are skipped. Even though the frame rate is not controlled by the
time code, it is necessary to know the frame rate to know when the frame column will roll over. The
frame rate will also tell us if the speed is pulled down and whether the clock is real time or not. So
time code is expressed with the frame rate.
Some common time codes are: 30 NDF, 29.97 NDF, 29.97 DF, 24 NDF, 25 NDF, 23.98 DF, and
23.98 NDF. There are also 30 DF and 24 DF formats where the counter runs too fast by .1
percent.
VITC, Subcode, and Linear Time Code
To better understand time code, we need to understand how it is recorded onto tape or imbedded in
a media fi le. Time code written onto video can be recorded two ways. In one system, the time code
for a particular frame is written into that frame. In analog video, it is written into the sync information
between the frames, the vertical interval. This is referred to as vertical interval time code (VITC).
There is a digital equivalent called subcode time code. In this case, the time code is written into the
digital information or metadata after all the image information is recorded. In both cases, a frame
number as time code is recorded as part of that frame. There is, therefore, a one-to-one relationship
between frames and numbers. With metadata, it is also possible to record several different time codes
into the frame at the same time.
It is also possible to record time code on a linear videotape track outside the video information. This
information can be recorded and played with the tape running at almost any speed. It need not have
a one-to-one relationship with the video frames as it is totally independent of the video. In fact, it
can be recorded onto any tape or media, not just video. If linear time code is recorded onto videotape
at the same frame rate as the video, there will be a one-to-one relationship with the video as every
video frame will lie opposite a linear time code number residing in its own track. DV video uses
subcode time code. DVCam and DVC Pro formats use both subcode and linear time code. In normal
usage, the two tracks match exactly. The linear time code is used for high-speed shuttling as it can
be read at almost any speed.
In video, it is necessary that the time code format match the video format. Therefore, NTSC video
will always use 29.97 DF or NDF. In audio formats, there are no frames to match. However, if syncing
is going to be done to the time code, the time code frame rate on the audio recording must match
the frame rate on the video. Changing the speed of the recording will also change the speed of the
time code. For example, time code can be recorded onto a DAT tape as 30 NDF. If this audio is
“pulled down” or slowed by .1 percent, the time code becomes 29.97 NDF. For this reason, the time
code formats usually used for audio recording are 29.97 NDF or DF for shooting on video, 30 NDF
for shooting on fi lm. Depending on the workfl ow, 30 DF, 24 NDF, and 24 DF can also be used for
shooting on fi lm.
182