Adobe AFTER EFFECTS 5.5 Help Manual page 44

Adobe After Effects Help
Using Help | Contents
Some programs, including After Effects and current versions of Media 100, label the field
order when rendering interlaced video files. When you import a labeled video file, After
Effects honors the field order label automatically. You can override the field order using
the Interpretation Rules file. For more information about field order, see "Specifying inter-
pretation rules" on page 27.
If a file does not contain a field order label, you can match the original field order of your
footage. If you are not sure which field order was used to interlace a footage item, use the
procedure below to find out.
To determine the original field order:
1 Select the item in the Project window.
2 Choose File > Interpret Footage > Main.
3 In the Interpret Footage dialog box, select Upper Field First from the Separate Fields
pop-up menu, and then click OK.
4 In the Project window, press Alt (Windows) or Option (Mac OS) as you double-click the
footage to open it in a Footage window.
5 If the Time Controls palette is not visible, choose Window > Show Time Controls.
6 In the Footage window, find a segment that contains one or more moving areas.
7 Using the Frame Advance button ( ) on the Time Controls palette, step forward at least
five frames in the Footage window. Moving areas should move consistently in one
direction. If the moving areas move backward every other frame, the wrong field-
separation option has been applied to the footage.
Note: Analog capture cards can vary. DV or footage captures from IEEE 1394 FireWire/
i.Link are always lower field first.
Field rendering
When you render a composition containing separated footage, set the Field Rendering
option to the same field order as your video equipment. If you don't field-render the
composition, or if you field-render with the incorrect settings, the final movie may appear
too soft, jerky, or distorted. See "Testing the field-rendering order" on page 302.
About 3:2 pulldown
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. The first frame of film is copied to fields 1 and 2 of the first frame of video, and also
to field 1 of the second video frame. The second frame of film is then spread across the
next two fields of video—field 2 of the second video frame and field 1 of the third frame of
video. This 3:2 pattern is repeated until four frames of film are spread over five frames of
video, and is then repeated.
The 3:2 pulldown process results in whole frames (represented by a W) and split-field
frames (represented by an S). The three whole video frames contain two fields from the
same film frame. The remaining two split-field frames contain a video frame from two
different film frames. The two split-field frames are always adjacent to each other. The
phase of 3:2 pulldown refers to the point at which the two split-field frames fall within the
first five frames of the footage.
Using Help | Contents
| Index
| Index
Preparing and Importing Footage
Back
Back
44
44