Filter crop
  Crop the input video.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
crop AVOptions:
  out_w             <string>     ..FV..... set the width crop area expression (default "iw")
  w                 <string>     ..FV..... set the width crop area expression (default "iw")
  out_h             <string>     ..FV..... set the height crop area expression (default "ih")
  h                 <string>     ..FV..... set the height crop area expression (default "ih")
  x                 <string>     ..FV..... set the x crop area expression (default "(in_w-out_w)/2")
  y                 <string>     ..FV..... set the y crop area expression (default "(in_h-out_h)/2")
  keep_aspect       <boolean>    ..FV..... keep aspect ratio (default false)
  exact             <boolean>    ..FV..... do exact cropping (default false)


