You
can limit the keyed area by drawing a crop box on the image.
To
draw the crop box:
In
the Keyer, click Setup.
The Setup menu appears.
Enable
Draw Crop.
Draw
the crop box by selecting a point on the image and dragging the
cursor diagonally.
Click
Crop to enable the crop box.
Keying operations now affect only the cropped
area.
NoteWhen the clip is processed with the crop
box enabled, only the cropped area is keyed. Remember to disable
the crop box if you want to apply the key to the entire frame.