[FFmpeg-user] Invalid duration specification for force_key_frames

Moritz Barsnick barsnick at gmx.net
Thu Sep 3 13:57:35 CEST 2015

On Thu, Sep 03, 2015 at 13:41:20 +0200, Frans Gouverne wrote:
> I use:
> -force_key_frames expr:gte(t,n_forced*5)
> It gives me the following error:
>   Invalid duration specification for force_key_frames:
> expr:gte(t,n_forced*5)

Well, then something is wrong with your ffmpeg version. Please post a
full command line and complete, uncut console output from a
reproducible attempt.

Your expression works fine for me on Linux with said quotes (though I'm
not sure it makes sense):

$ ffmpeg -f lavfi -i testsrc -c:v libx264 -t 100 -force_key_frames "expr:gte(t,n_forced*5)" -f null -
[I'm not quoting the output here. I simply don't get an error.]


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