Filter anequalizer
  Apply high-order audio parametric multi band equalizer.
    Inputs:
       #0: default (audio)
    Outputs:
        dynamic (depending on the options)
anequalizer AVOptions:
  params            <string>     ..F.A.... (default "")
  curves            <boolean>    ..FV..... draw frequency response curves (default false)
  size              <image_size> ..FV..... set video size (default "hd720")
  mgain             <double>     ..FV..... set max gain (from -900 to 900) (default 60)
  fscale            <int>        ..FV..... set frequency scale (from 0 to 1) (default log)
     lin             0            ..FV..... linear
     log             1            ..FV..... logarithmic
  colors            <string>     ..FV..... set channels curves colors (default "red|green|blue|yellow|orange|lime|pink|magenta|brown")


