User Guide

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Adobe After Effects Help Rendering a Movie
Using Help | Contents | Index Back 302
to 200% to create a 640 x 480 movie. For a composition rendered at full resolution, the
image quality will usually be acceptable.
Note: Do not use stretching to change the vertical dimensions of a movie with field
rendering. Stretching vertically mixes the field order, which distorts any motion. Use either
cropping or composition nesting if you need to vertically resize a field-rendered movie.
• Crop the movie. To enlarge a movie by a few pixels, increase the size using negative
values for the Crop options in the Output Module Settings dialog box. For example, to
increase the size of a movie by 2 pixels, type –2 in the Cropping section of the Output
Module Settings dialog box. Remember that negative cropping adds to one side of a
movie, so objects originally centered in the composition may not appear centered
when the movie is cropped.
Note: Adding an odd number of pixels to the top of a field-rendered movie reverses the
field order. For example, if you add one row of pixels to the top of a movie with Upper Field
First field rendering, the field-rendering order then becomes Lower Field First. Remember
that if you add pixels to the top of the movie, you need to crop from the bottom row of the
movie to maintain the original size. See “Using interlaced video in After Effects” on page 43
and “Field-rendering considerations” on page 282.
Creating low-resolution movies for testing motion
You can test the motion of a high-quality composition by quickly creating a low-
resolution, or thumbnail, movie. Do this by making a movie at a resolution less than full
(using the Resolution pop-up menu in the Render Settings dialog box). After Effects
creates a movie with dimensions proportional to the resolution.
For example, if your composition is 640 x 480 pixels and you make a movie at quarter
resolution, the resulting movie will be 160 x 120 pixels (one-sixteenth the size of the
composition). This thumbnail renders almost 16 times faster than at full resolution. You
can then play the thumbnail on your system to get a good idea of what motion will be like
in your final, full-sized movie. You can also enlarge the thumbnail in a movie-playing appli-
cation to see playback at full size. In addition, you can use RAM preview for testing
purposes.
Testing the field-rendering order
A simple test can determine the order in which your video equipment requires fields.
When you make a movie, the rendering order (Upper Field First or Lower Field First) should
be synchronized with the method used by your equipment, or your movie will appear
distorted.
Note: The field order with which you record to video equipment can be altered by changes
in the hardware or software of your production setup. For example, changing your video
board, device control software, or VCR after setting the field order can reverse your fields.
Therefore, any time you make a change to your setup, run this test for field-rendering
order.
The test takes about 15 to 20 minutes and involves creating two movie versions of the
same composition (one rendered with Upper Field First and one with Lower Field First),
and then taping and playing the movies to see which choice looks right.