Filter lumakey
  Turns a certain luma into transparency.
    slice threading supported
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
lumakey AVOptions:
  threshold         <int>        ..FV..... set the threshold value (from 0 to 65535) (default 0)
  tolerance         <int>        ..FV..... set the tolerance value (from 0 to 65535) (default 1)
  softness          <int>        ..FV..... set the softness value (from 0 to 65535) (default 0)

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

