Filter maskedclamp
  Clamp first stream with second stream and third stream.
    slice threading supported
    Inputs:
       #0: base (video)
       #1: dark (video)
       #2: bright (video)
    Outputs:
       #0: default (video)
maskedclamp AVOptions:
  undershoot        <int>        ..FV..... set undershoot (from 0 to 65535) (default 0)
  overshoot         <int>        ..FV..... set overshoot (from 0 to 65535) (default 0)
  planes            <int>        ..FV..... set planes (from 0 to 15) (default 15)

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

