Filter tmix
  Mix successive video frames.
    slice threading supported
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
tmix AVOptions:
  frames            <int>        ..FV..... set number of successive frames to mix (from 1 to 128) (default 3)
  weights           <string>     ..FV..... set weight for each frame (default "1 1 1")
  scale             <float>      ..FV..... set scale (from 0 to 32767) (default 0)

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

