ADOBE AFTER EFFECTS 7.0
User Guide
596
resulting composition rendered at full resolution and best quality will have excellent image quality, better than if you
had rendered using a reduced resolution.
Stretch the composition This method produces the highest quality reduced-size movie but is slower than nesting.
For example, if you create a 640 x 480 composition and render it at full resolution, you can set the stretch value in
the Output Module Settings dialog box to 50% to create a 320 x 240 movie. For a composition rendered at full
resolution, the image quality is excellent when the Stretch Quality is set to High.
Note: Do not use stretching to change the vertical dimensions of a movie when field rendering is on. Stretching vertically
mixes the field order, which distorts motion. Use either cropping or composition nesting if you need to vertically resize a
field-rendered movie.
Crop the composition Thismethodisidealforreducingthesizeofamoviebyafewpixels.UsetheCropoptionsin
the Output Module Settings dialog box. Remember that cropping cuts off part of the movie, so objects centered in
the composition may not appear centered unless the movie is cropped evenly on opposite edges.
Crop to a region of interest To render just a portion of the composition frame, select a region of interest in the
Composition panel. Then, select the Region of Interest option in the Output Module Settings dialog box before
rendering. (See “To change the region of interest” on page 118.)
Note: Cropping an odd number of pixels from the top of a field-rendered movie reverses the field order. For example, if
you crop one row of pixels from the top of a movie with Upper Field First field rendering, the field-rendering order then
becomes Lower Field First. Remember that if you crop pixels from the top of the movie, you need to add to the bottom
row of the movie to maintain the original size. If you are willing to lose one scan line, this gives you a way to output two
movies from one render, each with a different field order. (See “About field separation and pulldown” on page 99 and “To
test field-rendering order” on page 597.)
Render the composition at a reduced resolution This is the fastest method to create reduced-size movies. For
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.
Enlarging a movie
Increasing the size of the output from a rendered composition reduces the image quality of a movie and is not recom-
mended.Ifyoumustenlargeamovie,tomaintainhighestimagequality,enlargeacompositionthatwasrenderedat
full resolution and highest quality using one of the following methods:
Nest the composition Create a new composition at the larger dimensions and nest the smaller composition inside it.
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.
Stretch the composition For example, if you create a 320 x 240 composition and render it at full resolution, you can
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.
To Next Page
Loading...