Thanks, guys! It actually looks like Tmpenc was just reporting it wrong for some reason. I've got the gap down to about a single frame (no way to do it any closer than that without the original, unencoded capture as there's either a B or I frame right on the last frame of black), and it's much less annoying now, not any worse than a layer change on a DVD-9. Did a couple of captures from the "original" torrented files, and my newly snipped version, and it doesn't look like I lost anything at all!