Apple Motion 5.1.1 - Manual (Page 180)

Chapter 6 Create and manage projects 180
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None/Ignore: This is the default setting for objects with no alpha channel. This option also
allows you to ignore an object’s alpha channel, so the entire object appears solid.
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Straight: These alpha channels are kept separate from the red, green, and blue channels of
an image. Media files using straight alpha channels appear fine when used in a composition,
but they may look odd when viewed in another application. Translucent effects such as
volumetric lighting or lens flares in a computer-generated image can appear distorted until
the clip is used in a composition. If Straight is chosen but you see a black, white, or colored
fringe around the object, this parameter is incorrectly set and should be changed to a
Premultiplied option, depending on the color of the fringe.
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Premultiplied-Black: This type of alpha channel is multiplied with the clip’s red, green, and
blue channels. As a result, objects with premultiplied alpha channels look correct, even with
translucent lighting effects, because the entire image is precomposited against a solid color.
This option interprets alpha channels that are precomposited against black.
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Premultiplied-White: This option interprets alpha channels that are precomposited
against white.
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Guess Alpha Type: This option forces Motion to analyze the file in an attempt to figure out
what kind of alpha channel is used. If you’re unsure, use this setting.
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Invert Alpha: Select this checkbox to invert an alpha channel that is incorrectly generated in
reverse. Ordinarily, an alpha channel is a grayscale channel, where white represents areas of
100 percent opacity (solid), gray regions represent translucent areas, and black represents 0
percent opacity (transparent).
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Pixel Aspect Ratio: Use this pop-up menu to set the type of pixel relevant to the project, square
or nonsquare. In general, objects created for computer display, film, and high-definition video
use square pixels, while objects created for some video formats (such as DV, HDV, DVCPRO HD,
and others) use nonsquare pixels. A value field to the right of this pop-up menu displays the
numeric aspect ratio, in case you need a custom ratio. By correctly identifying each object you
add to your project, you can mix and match both kinds of media.
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Field Order: Use this pop-up menu to choose a field order that matches the field order of
the device used to capture an interlaced clip. There are two choices: Upper (Odd) or Lower
(Even). If you choose incorrectly, you’ll notice that the video stutters during playback. When
this happens, choose the opposite field order. Clips shot on film or with a progressive scan
video camera have no interlacing; therefore Field Order should be set to None. By correctly
identifying each object in your project, you can mix and match clips with a different field
order. For more information, see
Field order on page 1055.
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Frame Rate: Use this pop-up menu to choose a frame rate in frames per second (fps) that
matches a clip’s native rate. For example, film is 24 fps, PAL video is 25 fps, and NTSC video is
29.97 fps. Additional frame rates are available for other video formats. If the frame rate you
require is not listed, enter a number in the text field to the right of the pop-up menu. If you
modify a QuickTime file’s frame rate but need to change it back to the file’s original rate,
choose “From file” at the bottom of the Frame Rate pop-up menu.
Although you can mix clips using different frame rates, clips playing at a frame rate different
from that of the project might not play smoothly.
Note: Project frame rates are determined by the project preset. To edit a preset or to create a
preset, choose Motion > Preferences and use the options in the Presets pane.
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Fixed Width and Fixed Height: Use these sliders (available for still images) to change the
resolution of source media. When the Large Stills control (in Motion Preferences) is set to Scale
to Canvas Size, these values display the resolution of the original file. For more information, see
Import large still images on page 167.
67% resize factor