[FFmpeg-user] overlay image on a video with less then a frame duration - bug?

Jonathan Baecker jonbae77 at gmail.com
Thu Aug 18 22:23:26 EEST 2022

Hello everybody,

I notice a strange behavior and I wanted to ask if this is a bug, or a 
technical limitation.

Lets say you have a clip, which is 300 seconds long, and you seek in 
with -ss 299.999 and then you overlay a image with shortest=1, ffmpeg 
will run endless without encoding anything.

my command for that is:

ffmpeg -ss 299.999 -i "input.mp4" -filter_complex 
-map "[vout1]" -f sdl "test"

I think the problem is, that the image loops one frame, and that one 
frame is longer then 1 ms, so the shortest parameter will try to fit the 
video to the image, which fail because the video is not long enough.

Is a very rare problem, but when ffmpeg is used in an automated 
environment this can happen and it will stop all following processes, 
because it stuck on this forever.

When this is a bug, I can open a ticket. But when this more a technical 
limitation, I let it like it is.

Have a nice day!


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