Filter swaprect
  Swap 2 rectangular objects in video.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
swaprect AVOptions:
  w                 <string>     ..FV..... set rect width (default "w/2")
  h                 <string>     ..FV..... set rect height (default "h/2")
  x1                <string>     ..FV..... set 1st rect x top left coordinate (default "w/2")
  y1                <string>     ..FV..... set 1st rect y top left coordinate (default "h/2")
  x2                <string>     ..FV..... set 2nd rect x top left coordinate (default "0")
  y2                <string>     ..FV..... set 2nd rect y top left coordinate (default "0")

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

