palettegen hangs when input has no duration defined

[Jozef Chutka]

Summary of the bug:

FFmpeg hangs in case palettegen is used and input has no explicit duration. -t is being ignored.

How to reproduce:

Be careful, following command hangs my win10 PC and hard restart is needed:

% ffmpeg -f lavfi -i color=color=#ffffff:size=100x100:rate=10 -filter_complex "[0]split[a][b];[a]palettegen[p];[b][p]paletteuse" -t 4 -y out.gif

Please notice "-t 4" is used, yet it seems to have no effect on palettegen.

Following works ok:

% ffmpeg -f lavfi -i color=color=#ffffff:size=100x100:rate=10:duration=4 -filter_complex "[0]split[a][b];[a]palettegen[p];[b][p]paletteuse" -t 4 -y out.gif

Not sure this is intended by design or not, but having to restart my computer I decided to log as bug.

Using ffmpeg version 2022-01-24-git-0a83ecbf48-full_build-www.gyan.dev

[Elon Musk]

That is expected by design of providing input of infinite duration.