code: public T setVideoFrameRate(Fraction frame_rate) {
      this.video_enabled = true;
      this.video_frame_rate = checkNotNull(frame_rate);
      return getThis();
    }
docs: Sets the video's frame rate
  
  @param frame_rate Frames per second
  @return this
  @see net.bramp.ffmpeg.FFmpeg#FPS_30
  @see net.bramp.ffmpeg.FFmpeg#FPS_29_97
  @see net.bramp.ffmpeg.FFmpeg#FPS_24
  @see net.bramp.ffmpeg.FFmpeg#FPS_23_976