[FFmpeg-user] Frequency response of an ffmpeg equalizer filter

[Nicolas VAMBAIRGUE]

Hello,


I'm starting to use the ffmpeg filters, using the documentation. It 
seems working but, I don't find the way to get the frequency response of 
a filter. For example, let's say I'm applying this filter :

equalizer=f=7000:t=q:w=2:g=2,equalizer=f=1000:t=q:w=1:g=3,equalizer=f=80:t=q:w=2:g=-30

in the following command :

ffmpeg -re -i /home/dr_click/live.wav -acodec pcm_s16be -ar 44100 -ac 2 
-f rtp -af 
"equalizer=f=7000:t=q:w=2:g=2,equalizer=f=1000:t=q:w=1:g=3,equalizer=f=80:t=q:w=2:g=-30" 
rtp://127.0.0.1:1234

It works, I'm hearing a distorted sound. And what I'd like to know, with 
such a filter, is the db gain for the 2000 Hz signal or for the 150Hz 
signal or any other frequency with a query like : give me your frequency 
and I'll tell you which gain is applied at this frequency with the 
defined filter.


Thank you for your help,


Nicolas