[Libav-user] ffmpeg showspectrum to file

[wm4]

On Wed, 7 May 2014 11:44:26 -0700
Ricky Huang <rhuang.work at gmail.com> wrote:

> Hello all,
> 
> I am experimenting to the showspectrum filter.  According to the example at http://www.ffmpeg.org/ffmpeg-filters.html#Examples-11:
> 
> > ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1]; [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
> 
> but I cannot figure out how to output the showspectrum result to a saved video with ffmpeg command.  When I adopt the ffplay command to ffmpeg:
> 
> > ./ffmpeg -i Q-full-circle.mp3 -vf showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt -y full-circle.avi
> 
> 
> the command executes without error, the video file gets generated, but no video is produced.

AFAIK -vf is for video-to-video filters only. You either need a
"complex" graph, or you use the lavfi thing as input like you did with
ffplay.

> 
> Thanks in advance!
>