Trim is outputting off-by-one frames

[GrygrFlzr]

When using A-mo's Trim option, the frame numbers in the file title seem to be as requested, but the resulting image frames are one frame early.

As an example:

• Line is timed to frames 100-120
• A-mo output has correct filename [100-120]
• A-mo output will have images from frames 99-119 instead

[L11K]

Same here. Supposed to be 78 frames and ends up being 77.

[petzku]

I haven't noticed problems like this (using the ffmpeg preset with ffmpeg version git-2020-04-03-52523b6)

Some more information would probably help with debugging. Which encoder/preset/command are you using? Posting files which can reproduce this would probably also help.

[petzku]

Just had this happen using ffmpeg, on a 29.970 fps file. Could this be related to some faulty timestamp/frame conversion math in Aegisub itself, or maybe something wrong with the video file's timestamps? The video file was also behaving strangely in Aegisub (showing an inconsistent frame for a given timestamp).

Remuxing the (mp4) file into mkv seems to have fixed both problems.