I've been messing around with Avisynth and
VirtualDub with varying results. I've used scripts I've found in various places, here, YouTube, other forums...I've even asked ChatGPT to write a script or two, though they invariably come back using something I neither have nor can find. Sometimes I use what I find as-is, just copy/paste; sometimes I slightly modify, sometimes I try to Frankenstein them together, probably unwisely.
Anyway, when I start rendering in
VirtualDub, I get the popup window with the processing information. A handful of times, it's taken a relatively short time, just a few hours, but more often than not, it will display the estimated time as a few hours....then I check back and it's gone up an hour or two. Once or twice it's started out saying something like 4 hours remaining, then creeped up to 8 hours. So I'll leave it going when I leave for work, check it when I get back and it says it still has 11 hours remaining, after running for 10 or 12 already. I think there was one that went from 4 or 5 hours estimated when I started it to more than 30 still remaining AFTER I'd already given it 10. At what point can I safely assume I've messed something up?