Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 632

AFTER EFFECTS CS3 626
User Guide
This is the fastest method to create reduced-size movies. For
Render the composition at a reduced resolution
example, if you create a 640 x 480 composition, you can set the composition resolution to one half, reducing the size
of the rendered composition to 320 x 240. You can then create movies or images at this size. Note that the reduced
resolution reduces the sharpness of the image and is best used for creating preview or draft movies.
Note: When rendering at reduced resolution, set the quality of the composition to Draft. Rendering at Best quality while
reducing resolution does not produce a clean image and takes longer to render than rendering at Draft quality.
See also
"Work with output module settings" on page 594
"Work in the Render Queue panel" on page 585
Scaling a movie up
Increasing the size of the output from a rendered composition reduces the image quality of a movie and is not recom-
mended. If you must enlarge a movie, to maintain highest image quality, enlarge a composition that was rendered at
full resolution and highest quality using one of the following methods:
Create a new composition at the larger dimensions and nest the smaller composition inside it.
Nest the composition
For example, if you create a 320 x 240 composition, you can place it in a 640 x 480 composition. Stretch the compo-
sition to fit the new larger composition size, and then collapse transformations by choosing Layers > Switches >
Collapse. The resulting composition rendered at full resolution and best quality will have better image quality than
if you had stretched the movie. However, this method also renders slower than if you created a composition and
stretched it.
Note: To create a draft movie with specific dimensions, use both the Stretch option and reduced resolution in the
rendered composition.
For example, if you create a 320 x 240 composition and render it at full resolution, you can
Stretch the composition
set the stretch value in the Output Module Settings dialog box 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.
To enlarge a movie by a few pixels, increase the size using negative values for the Crop options
Crop the composition
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 also
"Work with output module settings" on page 594
"Work in the Render Queue panel" on page 585