The problem is because iMovie is unforgiving of a glitchy frame from raw video. Fine: it’s the same as Basecamp being unforgiving of a broken line point. Funnily enough the solution is the same with both: break it down and surround it with ever-smaller parcels on either side of it until you find the offending ‘thing’ and kill it with your most fuck you keystroke.
Catch up tomorrow. If I find a rhinoceros.