Filter xmedian
  Pick median pixels from several video inputs.
    slice threading supported
    Inputs:
        dynamic (depending on the options)
    Outputs:
       #0: default (video)
xmedian AVOptions:
  inputs            <int>        ..FV....... set number of inputs (from 3 to 255) (default 3)
  planes            <int>        ..FV.....T. set planes to filter (from 0 to 15) (default 15)
  percentile        <float>      ..FV.....T. set percentile (from 0 to 1) (default 0.5)

framesync AVOptions:
  eof_action        <int>        ..FV....... Action to take when encountering EOF from secondary input  (from 0 to 2) (default repeat)
     repeat          0            ..FV....... Repeat the previous frame.
     endall          1            ..FV....... End both streams.
     pass            2            ..FV....... Pass through the main input.
  shortest          <boolean>    ..FV....... force termination when the shortest input terminates (default false)
  repeatlast        <boolean>    ..FV....... extend last frame of secondary streams beyond EOF (default true)

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

