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Add Alpha Compositor 363
Adding Image Lay er Events
Add Alpha Compositor
Rendering menu > Video Post > Video Post window >
Make su re the two child events are in the order you want
the Image Layer event to use them. > Select the two
events. > V ideo Post toolbar > Add Image Layer Event >
Choose Alpha Compositor from the Layer Plug-in list.
The Alpha Compositor composites the two images
using the
alpha channel (page 3–1001)
of the
foreground image. The background image appears
in areas where the foreground image’s alpha
channel is transparent.
There are no Setup options for this compositor.
Add Cros s Fade Compositor
Rendering menu > Video Post > Video Post window >
Make su re the two child events are in the order you want
the Image Layer event to use them. > Select the two
events. > V ideo Post toolbar > Add Image Layer Event >
Choose Cross Fade Compositor from the Layer Plug -in list.
Cross fade fades one image into another over time.
The Cross Fade Compositor composites the
twoimagesovertime,crossfadingfromthe
background image to the foreground image. The
rate of the cross fade is determined by the length of
the Cross Fade Transition filter’s time range.
There are no Setup options for this compositor.
Add P seudo A lpha Compos itor
Rendering menu > V ideo Post > V ideo Post window >
Make sure the two child events are in the order you want
the Image Layer event to use them. > Select the two
events. > Video Post toolbar > Add Image Layer Event >
Choose Pseudo-Alpha Compositor from the Layer Plug-in
list.
Pseudo alpha compositing
The Pseudo-Alpha Compositor composites a
foreground image against the background by
creat ing an a lpha channel for the foreground image
based on the foreground image’s upper-left-corner
pixel. All pixels in the foreground image that use
this color become transparent.
Because only one pixel color becomes transparent,
edges of the op aque areas in the foreground image
are aliased. Use this method when the foreground
image is a bitmap whose format does not have an
alpha channel.
There is also a
Pseudo Alpha Filter Event (page
3–360)
.
There are no Setup options for this compositor.