Apple Final Cut Pro 6 - Manual (Page 732)

Chapter 22 Refining Transitions Using the Transition Editor 399
III
Dragging the transition bar from the middle results in a roll edit, which moves the edit
point between two clips in a sequence. Dragging either of the transition edges
shortens or extends the transition.
Note: A roll edit adjusts the location of an edit point shared by two clips; the Out point
of the first clip and the In point of the second clip are moved simultaneously, or rolled.
This changes the location of the edit point in the sequence, as well as the duration of
each clip. For more information, see “
Using the Roll Tool to Change Where a Cut
Occurs ” on page 334.
Start and End Percentages of Transition
These sliders allow you to set the starting and ending percentages of the transition’s
visual effect. For example, if you are using an edge wipe, the default starting
percentage of 0 percent places the border of the wipe all the way to the left of the
image, essentially revealing all of the outgoing clip.
Halfway through the wipe, at the edit point, the wipe is at 50 percent, placing the
border of the wipe in the middle of the picture. You can now see half of the incoming
clip to the left and half of the outgoing clip to the right.
The start of an edge
wipe transition
The middle of an edge
wipe transition