Let me see if this helps:
#1 Transitions "Insufficient Content"
Shane's Stock Answer #1:
You need to make sure that your clips have enough media (called 'handles') at the beginning of the incoming clip and at the end of the outgoing clip for the transition. For example, if you have a 1 second (30 frame) dissolve, your in and out point need to be at least 15 frames from the edge of the clip.
What you are running into is that you are marking an out point at the end of a clip then adding a cross dissolve, say 20 frames in duration. Since the dissolve is centered on the cut, it will start 10 frames before the cut, and try to go 10 frames AFTER the cut...which it can't do.
What you need to do is plan how long your dissolve will be and back-time your cut so that it works.
a full 1 second crossfade reaches 15 frames into each clip. So, if you want to change a cut to a crossfade, there has to be at least 15 additional frames of each clip.
Say you're trying to crossfade from one clip into the very first frame of a second clip. FCP cannot 'create' 15 more frames of the second clip to do a crossfade. If they're not there, you're out of luck.
FCP has to extend the end of your first clip by 1/2 of your transition length, and the beginning of your second clip by 1/2 of your transition length, so those frames need to be in your system. The nature of a crossfade is mixing two clips together.
Shane
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