Filter fps
  Force constant framerate.
    Inputs:
       #0: default (video)
    Outputs:
       #0: default (video)
fps AVOptions:
  fps               <video_rate> ..FV..... A string describing desired output framerate (default "25")
  start_time        <double>     ..FV..... Assume the first PTS should be this value. (from -DBL_MAX to DBL_MAX) (default DBL_MAX)
  round             <int>        ..FV..... set rounding method for timestamps (from 0 to 5) (default near)
     zero            0            ..FV..... round towards 0
     inf             1            ..FV..... round away from 0
     down            2            ..FV..... round towards -infty
     up              3            ..FV..... round towards +infty
     near            5            ..FV..... round to nearest
  eof_action        <int>        ..FV..... action performed for last frame (from 0 to 1) (default round)
     round           0            ..FV..... round similar to other frames
     pass            1            ..FV..... pass through last frame


