Filter aphasemeter
  Convert input audio to phase meter video output.
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (video)
aphasemeter AVOptions:
  rate              <video_rate> ..FV.... set video rate (default "25")
  r                 <video_rate> ..FV.... set video rate (default "25")
  size              <image_size> ..FV.... set video size (default "800x400")
  s                 <image_size> ..FV.... set video size (default "800x400")
  rc                <int>        ..FV.... set red contrast (from 0 to 255) (default 2)
  gc                <int>        ..FV.... set green contrast (from 0 to 255) (default 7)
  bc                <int>        ..FV.... set blue contrast (from 0 to 255) (default 1)
  mpc               <string>     ..FV.... set median phase color (default "none")


