Filter extrastereo
  Increase difference between stereo audio channels.
    Inputs:
       #0: default (audio)
    Outputs:
       #0: default (audio)
extrastereo AVOptions:
  m                 <float>      ..F.A.... set the difference coefficient (from -10 to 10) (default 2.5)
  c                 <boolean>    ..F.A.... enable clipping (default true)

This filter has support for timeline through the 'enable' option.

