Filter perspective
  Correct the perspective of video.
    slice threading supported
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
perspective AVOptions:
  x0                <string>     ..FV..... set top left x coordinate (default "0")
  y0                <string>     ..FV..... set top left y coordinate (default "0")
  x1                <string>     ..FV..... set top right x coordinate (default "W")
  y1                <string>     ..FV..... set top right y coordinate (default "0")
  x2                <string>     ..FV..... set bottom left x coordinate (default "0")
  y2                <string>     ..FV..... set bottom left y coordinate (default "H")
  x3                <string>     ..FV..... set bottom right x coordinate (default "W")
  y3                <string>     ..FV..... set bottom right y coordinate (default "H")
  interpolation     <int>        ..FV..... set interpolation (from 0 to 1) (default linear)
     linear          0            ..FV..... 
     cubic           1            ..FV..... 
  sense             <int>        ..FV..... specify the sense of the coordinates (from 0 to 1) (default source)
     source          0            ..FV..... specify locations in source to send to corners in destination
     destination     1            ..FV..... specify locations in destination to send corners of source
  eval              <int>        ..FV..... specify when to evaluate expressions (from 0 to 1) (default init)
     init            0            ..FV..... eval expressions once during initialization
     frame           1            ..FV..... eval expressions per-frame

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

