[FFmpeg-user] ffmpeg -f lavfi with -i color / r flag behaves strangely

Andy Furniss adf.lists at gmail.com
Sun May 29 11:51:31 CEST 2016

gf wrote:
> 2016-05-29 10:40 GMT+02:00 Carl Eugen Hoyos <cehoyos at ag.or.at>:
>> gf <fortyman <at> gmx.de> writes:
>>> ffmpeg -f lavfi -i color=d=10 -r 50 -c copy test2.avi
>> How is this supposed to work / what kind of output do you
>> expect?
>> In case this isn't clear: Neither duplicating nor dropping
>> frames is possible with -codec copy, not even for rawvideo.
>> (Duplicating and / or dropping is the desired effect of the
>> output option -r.)
>> Carl Eugen
> Hm, I still don't seem to understand what the -r flag does in this case
> then.
> why is -i color=d=10:r=50 different from -i color=d=10 -r 50 ?

It's a different r :r=50 is a suboption of color which tells it to 
generate 50 fps. the -r 50 is an option that tells ffmpeg you want
the output to be converted to 50 fps by dup/drop - but it doesn't
work with copy.

If you use -r before -i it has a different effect from after, on
normal files = override whatever the input file framerate is.

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