Apple Final Cut Pro HD (4.5): New Features - Manual (Page 76)

76 Chapter 4 Editing Film With Final Cut Pro in a PAL Environment
Some Background About Working With 24 @ 25 in Final Cut Pro
When you conform PAL video from 25 fps to 24 fps, the result is that the clips play at
24 fps in actual time. This means the speed appears natural and normal as you are
editing—it’s the same speed at which the original material was filmed. But the 24 @ 25
timecode you see displayed by Final Cut Pro is counting 25 fps. It shows a new timecode
second starting after the frame numbered “:24” by the timecode, even though in actual
time the new second starts after the frame marked “:23” by the timecode. The picture
below illustrates an example of this. Notice that though the same frames in both columns
are played at different actual times, they still have the same timecode associated with
them, as highlighted by the frames at timecode 01:00:00:23.
How can it be that the timecode counts at 25 fps while the editing timebase of your
sequence is 24 fps? For one thing, the timecode track stored within the source media
file did not change—it is still 25 fps—even though the source media video rate was set
to play at 24 fps. And, when you conformed the PAL video from a 25 fps to a 24 fps
rate, no frames were actually added or taken away. What changed is that the frames
were slowed down to play a little later in actual time, while the 25 fps timecode count
did not change. This makes the most sense if you think of timecode in this situation as
simply a sequential labeling mechanism instead of a time-tracking mechanism. For
example, in actual time, the frame labeled “01:00:00:23” plays later than it did before, so
the number “01:00:00:23” no longer conveys how much actual time has passed. It is
now simply a unique label to identify that frame.
Most importantly, regardless of how fast or slow the video plays in Final Cut Pro, the
source timecode associated with each frame in Final Cut Pro still corresponds to the
timecode for those same frames on the source media tapes. This allows an accurate
25 fps EDL to be exported from the sequence.
PAL video timecode Frame Frame
0 second
actual
clock time
25 fps PAL video
01:00:00:00
01:00:00:01
01:00:00:02
01:00:00:03
01:00:00:20
01:00:00:21
01:00:00:22
01:00:00:23
01:00:00:24
01:00:01:00
Timecode shown in Final Cut Pro
Conformed to 24 fps
01:00:00:00
01:00:00:01
01:00:00:02
01:00:00:03
01:00:00:19
01:00:00:20
01:00:00:21
01:00:00:22
01:00:00:23
01:00:00:24
01:00:01:02 01:00:01:01
01:00:01:01 01:00:01:00
1 second
actual
clock time
UP01022.Book Page 76 Tuesday, March 23, 2004 7:32 PM