Filter premultiply
  PreMultiply first stream with first plane of second stream.
    slice threading supported
    Inputs:
        dynamic (depending on the options)
    Outputs:
       #0: default (video)
premultiply AVOptions:
  planes            <int>        ..FV..... set planes (from 0 to 15) (default 15)
  inplace           <boolean>    ..FV..... enable inplace mode (default false)

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

