Setting Frame Rate; Setting Resolution - Adobe AFTER EFFECTS 7.0 Manual

Setting frame rate

The composition frame rate determines the number of frames displayed per second. Frame rate is usually deter-
mined by the type of output you produce. NTSC video has a frame rate of 29.97 frames per second (fps), PAL video
has a frame rate of 25 fps, and motion picture film has a frame rate of 24fps. Depending on the broadcast system,
DVD video can have the same frame rate as NTSC video or PAL video, or a frame rate of 23.976. Video intended for
CD-ROM or the web is often 10 to 15 fps.
Each motion-footage item in a composition can also have a frame rate, and the relationship between the footage-
item frame rate and the composition frame rate determines how smoothly the layer plays. For example, if the
footage-item frame rate is 30 fps and the composition frame rate is 30fps, whenever the layer advances one frame,
the next composition frame is displayed. If the footage-item frame rate is 15 fps and the composition frame rate is
30 fps, then two composition frames are displayed before the current layer advances one frame, unless frame
blending is enabled.
When you use footage that was shot or rendered at the NTSC-standard rate of 29.97 fps and the composition frame
rate is 30fps, approximately two footage frames will be repeated every minute to compensate for the differing rates.
To avoid repeated frames, make sure that your composition frame rate matches your source footage, or enable frame
blending for the layer.
Setting the composition frame rate to twice the rate of the output format causes After Effects to display each field of
interlaced source footage as its own, separate frame in the Composition panel. This process lets you set keyframes on
individual fields and gain precision when animating masks.

Setting resolution

Resolution determines the dimensions of the image in pixels, which affects the image quality of the rendered compo-
sition. Setting a low resolution significantly increases frame-rendering speed and decreases the amount of memory
required to render. You can use a low-resolution setting when animating or previewing a movie, and then increase
the resolution before rendering your final movie.
Select one of the following resolution settings in the Composition Settings dialog box:
Renders each pixel in a composition. This setting gives you the best image quality, but takes the longest to
Full
render.
Renders one-quarter of the pixels contained in the full-resolution image—half the columns and half the rows.
Half
This results in a rendering time approximately one-fourth of the time required to render the entire image at full
resolution.
Renders one-ninth of the pixels contained in the full-resolution image. This results in a rendering time
Third
approximately one-ninth of the time required to render the entire image at full resolution.
Renders one-sixteenth of the pixels contained in the full-resolution image. This results in a rendering time
Quarter
approximately one-sixteenth of the time required to render the entire image at full resolution.
Renders the image at the resolution you specify.
Custom
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