@Olly Funkster (Funkster) Something like that. Not sure how this system works, but some can mark a bug as "upstream." I don't see any way for me to do that.

I am now fairly positive that the problem is in ffmpeg. I have submitted a bug on the ffmpeg bug tracker detailing my findings: https://trac.ffmpeg.org/ticket/6307

You certainly know more than I, but I think you're right about it being a library difference. Here's my ffprobe output:

@Stephen Swaney (stiv) Oh, I agree completely. It's just the easiest way to get a small clip that exhibits the problem. It acts exactly like the larger (3.3GB), unmodified clip. I was using ffmpeg to create the clip, but whatever it does to the newly created file, the behavior is not the same.

So... Yeah, apparently the clip I uploaded does not exhibit the same properties as the original file. I short, the original file works as I described. The clip, which I created with ffmpeg -i 00008.MTS -c copy -t 10 clip.MTS, has the problem in all of the versions I've tried.