Apple Final Cut Pro 6 User Manual
Page 1895
412
If you edit an hour-long program on NTSC video, the 30 fps timecode will indicate the
last frame of the program is frame 108,000, labeled as timecode 01:00:00:00 (non-drop
frame). However, the table above shows that because the video actually runs at
29.97 fps (each frame is slightly longer than if it were running at 30 fps), one hour has
actually passed at frame 107,892 (3.6 seconds earlier than the 30 fps timecode shows).
What editors wanted, particularly in television environments, was a method of frame
addressing that accurately reflected how much time had passed.
Drop frame timecode was invented to compensate for the discrepancy between
29.97 and 30 fps. Every minute except each tenth minute, two timecode numbers are
dropped from the timecode count. This drop frame mode of 30 fps timecode remains
accurate compared to the actual time passed, with a strange side effect that two
numbers each minute vanish from the count.
Frame Count
Timecode labels
(30 fps)
Time passed
(29.97 fps)
Error between
timecode number
and real time
0
0
0
0
1
1/ 30th second
1/29.97th second
Negligible
30
= 30/30ths of a second
= 1 second
= 30/29.97ths
of a second
= 1.001 seconds
0.001 seconds
60
= 60/30ths of a second
= 2 seconds
= 60/29.97ths
of a second
= 2.002 seconds
0.002 seconds
1800
1800/30ths of a second
= 60 seconds
= 1 minute
=1800/29.97ths
of a second
= 60.06 seconds
= 1.001 minutes
0.001 minutes
0.06 seconds
1.8 frames
18,000
= 18000/30ths
of a second
= 600 seconds
= 10 minutes
= 18000/29.97ths
of second
= 600.6 seconds
= 10.01 minutes
0.01 minutes
0.6 seconds
17.9 frames
108,000
= 108000/30ths
of a second
= 3600 seconds
= 1 hour
=108000/29.97ths
of a second
= 3603.6 seconds
= 1.001 hours
0.001 hours
3.6 seconds
107.89 frames