Apple Final Cut Pro 6 - Manual (Page 1227)

442 Part II Effects
The Choke slider adjusts the overall size of the matte, without changing the shape; the
Feather slider blurs the edges of the matte.
The parameters of the Garbage Matte filters can be keyframed, in the same way as the
parameters of any other filter. This can come in handy if you need to use one of the
Garbage Matte filters to crop out the outside edge of a green screen in a shot where
the camera is panning.
Example: Keyframing Garbage Mattes
In the following example, two sets of keyframes are created to compensate for a simple
pan in the clip being keyed.
1 With the playhead on the first frame of a clip, apply and adjust the Four-Point Garbage
Matte filter.
For more details about using this filter, see “ Example: Using the Four-Point Garbage
Matte Filter ” on page 440.
2 Once you’ve created the proper shape for the first frame of the clip, click the keyframe
buttons for the Point 1, Point 2, Point 3, and Point 4 parameters.
The finished matte image
Create keyframes for
all four points.
Click keyframe buttons
to create keyframes.