Filter boxblur
  Blur the input.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
boxblur AVOptions:
  luma_radius       <string>     ..FV..... Radius of the luma blurring box (default "2")
  lr                <string>     ..FV..... Radius of the luma blurring box (default "2")
  luma_power        <int>        ..FV..... How many times should the boxblur be applied to luma (from 0 to INT_MAX) (default 2)
  lp                <int>        ..FV..... How many times should the boxblur be applied to luma (from 0 to INT_MAX) (default 2)
  chroma_radius     <string>     ..FV..... Radius of the chroma blurring box
  cr                <string>     ..FV..... Radius of the chroma blurring box
  chroma_power      <int>        ..FV..... How many times should the boxblur be applied to chroma (from -1 to INT_MAX) (default -1)
  cp                <int>        ..FV..... How many times should the boxblur be applied to chroma (from -1 to INT_MAX) (default -1)
  alpha_radius      <string>     ..FV..... Radius of the alpha blurring box
  ar                <string>     ..FV..... Radius of the alpha blurring box
  alpha_power       <int>        ..FV..... How many times should the boxblur be applied to alpha (from -1 to INT_MAX) (default -1)
  ap                <int>        ..FV..... How many times should the boxblur be applied to alpha (from -1 to INT_MAX) (default -1)

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

