Filter threshold
  Threshold first video stream using other video streams.
    slice threading supported
    Inputs:
       #0: default (video)
       #1: threshold (video)
       #2: min (video)
       #3: max (video)
    Outputs:
       #0: default (video)
threshold AVOptions:
  planes            <int>        ..FV..... set planes to filter (from 0 to 15) (default 15)

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

