9

382 Chapter 19: Video Post-Production
rate of the cross fade is determined by the length of
the Cross Fade Transition filter’s time range.
Cross Fade fades one image into another over time.
There are no setup options for this compositor.
Procedure
TousetheCrossFadeCompositor:
1.
Add two Scene or Image Input events to the
queue.
2. Select both events and assign an Image Layer
event consisting of the Cross Fade C ompositor.
Pseudo A lpha Composi tor
Rendering menu > Video Post > Video 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. > Vi deo Post toolbar > Add Image Layer Event >
Choose Pseudo-Alpha Compositor from the Layer Plug-in
list.
Rendering menu > Video Post > Video Post window >
Select a Pseudo-Alpha Compositor. > Video Post toolbar
>EditCurrentEvent
The Pseudo-Alpha compositor composites a
foreground image against the background by
creating an alpha 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.
Pseudo Alpha compositing
Because only one pixel color becomes transparent,
edges of the opaque a reas in the foreg round image
are aliased. Use this method when the foreground
image is a bitmap whose format does not have an
alpha channel.
There a re no setup options for this compositor.
There is also a Pseudo Alpha filter event (page
3–346).
Procedure
To use the Pseudo A lpha Compositor:
1.
A dd two Scene or Image Input events to the
queue.
2. Select both events and assign an Image
Layer event consisting of the Pseudo Alpha
Composite Filter.