24 Versus 23.98 fps
Although the term 24p implies 24 frames per second, the value 24 is usually
inaccurate, because most people working within NTSC standards actually shoot at a
frame rate of 23.976 fps (commonly referred to as 23.98 fps). On the other hand, 24 fps
footage transferred to PAL, as well as most film, is recorded at exactly 24 fps.
Although it may be easier to say “24p,” keep in mind that in some cases, such as during
audio post-production, it’s critical to state the exact frame rate of your footage.
Appendix C
Working with 24p Video
419
V
If you edit 3:2 pull-down footage without removing the pull-down first, you need to be
particularly careful to match the five-frame pull-down cadence at every edit. Edits with
broken cadence, such as a repeating or out-of-order frame (for example, A, B, A, B, C, D)
can confuse reverse telecine operations. In general, you should avoid editing 29.97 fps
pull-down footage. Instead, remove the pull-down of your footage first, edit at
23.98 fps, then reinsert pull-down during output.
Several NTSC and 1080i60 HD camcorders can record using standard pull-down,
though advanced pull-down is usually recommended when recording 24p video.
However, for final playback on television or DVD, 3:2 pull-down is generally considered
to have the most acceptable quality of motion.
Before
(23.98 fps)
A
B
A
B B
C
C
D D D
A A B B B C C D D D A A B B B C C D D D A A B B
C C D D D A A B
B
B
C
C
D D D A
B
A
B B
C
C
D D
B
D
A
B
C
D A
D A
B
C
D A
B
C
D A
B
C
D
A B
C D
B
C
A
B
C
D
A A
B
B
C
C
D
D
Field
1
Field
2
Field
1
Field
2
Field
1
Field
2
Field
1
Field
2
D
Field
2
B
Field
1
A
B
A
B B
C
C
D D D
A
B
C
D A
D A
B
C
D A
B
C
D A
B
C
D
A B
C D
B
C
A A B B B C C D D D A A B B B C C D D D A A B B
C C D D D A A B
B
B
C
C
D D D A
B
A
B B
C
C
D D
B
D
A
B
C
D
A A
B
B
B
C
C
D D
D
Field
1
Field
2
Field
1
Field
2
Field
1
Field
2
Field
1
Field
2
Field
1
Field
2
3:2 Pull-Down
After
(29.97 fps)
Before
(29.97 fps)
After
(23.98 fps)
One second
3:2 Pull-Down Removal
420
Part V
Appendixes