Changing the Alignment of a Transition in the Timeline
Transitions can either start on, center on, or end on an edit point. This alignment can
be changed at any time. Changing the alignment of a transition allows you to precisely
control which frames are fully visible when a transition begins or ends.
To change the alignment of a transition in a sequence, do one of the following:
m
In the Timeline, select the transition, choose Sequence > Transition Alignment, then
choose another alignment from the submenu.
m
Control-click a transition, then choose another alignment from the shortcut menu.
m
Select a transition, then do one of the following:
 To start the transition at the edit point: Press Option-1.
 To center the transition on the edit point: Press Option-2.
 To end the transition at the edit point: Press Option-3.
The transition moves to the new alignment position.