Adobe AFTER EFFECTS 5.5 Help Manual page 45

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Phase occurs as a result of two conversions that happen during 3:2 pulldown: 24-fps film is
redistributed through 30-fps video, so each of four frames of 24-fps film is spread out over
five frames of 30(29.97)-fps video. First, the film is slowed down 0.1% to match the speed
difference between 29.97 fps and 30 fps. Next, each film frame is repeated in a special
pattern and mated to fields of video.
A
B
W
When you apply 3:2 pulldown to footage, one frame of the film (A) is separated into two or three
interlaced video fields (B), which are grouped into video frames containing two fields each.
Removing 3:2 pulldown from video transferred from film
When you transfer 24-fps film to 29.97-fps (NTSC) video, you use a process called 3:2
pulldown, in which the film frames are distributed across video fields in a repeating 3:2
pattern. It's important to remove 3:2 pulldown from video footage that was originally film,
so that effects you add in After Effects synchronize perfectly with the original frame rate of
film. Removing 3:2 pulldown reduces the frame rate by 4/5: from 30 to 24 fps or from 29.97
to 23.976 fps, which also reduces the number of frames you have to change. To remove 3:2
pulldown, you must also indicate the phase of the 3:2 pulldown. For more information, see
"About 3:2 pulldown" on page 44.
Before you remove 3:2 pulldown, separate the fields as either upper-field first or lower-
field first. Once the fields are separated, After Effects can analyze the footage and
determine the correct 3:2 pulldown phase and field order. If you already know the phase
and field order, choose them.
Note: If your footage file contains frames from different sources, the phase may not be
consistent. If this is the case, import the footage once for each phase. Then, add the
footage to your composition as many times as there are phases and trim each layer to use
only the appropriate frames for each phase.
To remove 3:2 pulldown from video transferred from film:
1 In the Project window, select the footage from which you want to remove 3:2 pulldown.
2 Choose File > Interpret Footage > Main.
3 In the Fields and Pulldown section, select Upper Field First or Lower Field First from the
Separate Fields pop-up menu.
4 Do one of the following and click OK:
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