Filter histeq
  Apply global color histogram equalization.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
histeq AVOptions:
  strength          <float>      ..FV.... set the strength (from 0 to 1) (default 0.2)
  intensity         <float>      ..FV.... set the intensity (from 0 to 1) (default 0.21)
  antibanding       <int>        ..FV.... set the antibanding level (from 0 to 2) (default none)
     none                         ..FV.... apply no antibanding
     weak                         ..FV.... apply weak antibanding
     strong                       ..FV.... apply strong antibanding

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

