Apple Final Cut Pro 7 - Manual (Page 782)

You can change the starting and ending percentages for the transition. This is an
excellent way of creating split-screen effects if you plan to export your sequence as an
EDL for import into another editing system. For more information on exporting EDLs,
see
“Importing and Exporting EDLs.”
For example, you can set both the starting and ending percentages to 50 percent. At
the start of the transition, a split-screen effect is created; half of the outgoing clip and
half of the incoming clip are revealed simultaneously and throughout the duration of
the transition.
The start of an edge
wipe transition, where the
start percentage is 50%
The start of the transition
in the Canvas
When the transition is complete, the image becomes the full-screen picture of the
incoming clip.
The end of an edge
wipe transition, where the
end percentage is 50%
The end of the transition
in the Canvas; the
split-screen effect is
maintained throughout
the transition.
782 Chapter 48 Refining Transitions Using the Transition Editor