Filter setdar
  Set the frame display aspect ratio.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
setdar AVOptions:
  dar               <string>     ..FV..... set display aspect ratio (default "0")
  ratio             <string>     ..FV..... set display aspect ratio (default "0")
  r                 <string>     ..FV..... set display aspect ratio (default "0")
  max               <int>        ..FV..... set max value for nominator or denominator in the ratio (from 1 to INT_MAX) (default 100)


