Selecting the Alignment
 
 
 

Determine how a transition aligns with the cut, which is the focus point of the transition. Select the alignment from the Transition Alignment box.

Select: To:
Up To Cut Start the transition at the number of frames before the focus point, as indicated in the Duration field. The transition ends at the focus point.
Centred Centre the transition over the focus point with an equal number of frames before and after the transition. If the transition has an odd length, the extra frame is always placed after the focus point.
From Cut Start the transition at the focus point and have it proceed into the incoming clip by the number of frames indicated in the Duration field.
Custom Create an asymmetric transition that can be offset from the cut point.