list index out of range

[pabl0]

After some recent change (Perhaps e7a4591 "Clipping subsampler refactor (#275)"?), some downloads fail with "list index out of range" type error. Not sure how they different from the normal "failed_to_subsample" / "ffmpeg error (see stderr output for details)" type, but I did not see these before, and subsample errors seem to occur slightly more often now. From samples I've checked, they are videos with quite many clips (like, 10+), but I see nothing out of the ordinary in the metadata compared to non-failing videos.

[pabl0]

Is 847e5e6 in #307 somehow related? cherry-picking that makes the number of this error go down significantly but still not to zero.