Having Handles at Edit Points
Clips must have handles if you want to transition between them. Handles are
additional media frames before the In point and after the Out point of your clips. The
first shot in a transition (the outgoing clip) needs a handle after its Out point, while the
second shot in a transition (the incoming clip) needs a handle before its In point.
If the In point of your incoming clip begins on the first frame of the clip’s media file,
you have no handle at the beginning (or head) of your clip. Likewise, if the Out point of
your outgoing clip ends on the last frame of the clip’s media file, you have no handle at
the end (or tail) of your clip. If the clips don’t have enough media for the transition,
Final Cut Pro attempts to make the longest transition possible with the available clip
handles. In some cases, you may end up with transitions as short as one frame, which
may be difficult to see in the Timeline and are generally not intended or useful.