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")
  dar_den           <float>      ..FV.... (from 0 to FLT_MAX) (default 0)
  max               <int>        ..FV.... set max value for nominator or denominator in the ratio (from 1 to INT_MAX) (default 100)


