Apple Cinema Tools 3 User Manual

Page 27

Chapter 1

Before You Begin Your Project

What Happens to the Timecode After Using Reverse Telecine
or Conform?

The Reverse Telecine feature (changing 30 fps video to 24 fps video) and the Conform
feature (changing either 25 fps or 30 fps video to 24 fps) directly affect the timecode of
the video frames. Since Cinema Tools must generate new 24 fps timecode for the frames
(based on the original timecode), you may see a difference between the burned-in
timecode numbers and the numbers shown in Final Cut Pro. Though the timecode
discrepancies between the window burn and Final Cut Pro timecodes may be confusing,
Cinema Tools tracks the new timecode of the 24 fps video and is able to match it back to
its original NTSC or PAL values, and thus back to the film’s key numbers.

This is what happens to the timecode: reverse telecine removes six frames per second,
so the timecodes continue to match at the beginning of each second. This means that
a clip that lasts for 38 seconds when played at its NTSC rate of 30 fps will still last for
38 seconds when played at the reverse telecined rate of 24 fps.

In the above illustration, the blue NTSC fields represent those that are removed during
the reverse telecine process. The window burn NTSC timecode will be different from
what Final Cut Pro shows for all frames except the first one of each second, regardless
of the clip’s length.

Using the Conform feature to change video rates causes more timecode changes, since
all the original frames are kept and you are actually changing the video’s speed. A clip
that plays for 38 seconds at its PAL rate of 25 fps will play for almost 40 seconds at the
conformed rate of 24 fps. After the first 24 frames, each frame that follows will have a
different timecode number as compared to the timecode of the 25 fps video.

1:10

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1:20 1:21 1:22 1:23 1:24 1:25 1:26 1:27 1:28 1:29 2:00 2:01 2:02