Emgu.CV.Capture.QueryFrame C# (CSharp) Метод

      public virtual Image<Bgr, Byte> QueryFrame()
      {
         return Grab() ? RetrieveBgrFrame(0) : null;
      }

        public void write() {
            int codec = Emgu.CV.CvInvoke.CV_FOURCC('P', 'I', 'M', '1');

            int fps = 25;
            if (list_timestamps.Count > 0)
            {
                String tempvideopath = Program.getConfiguration().Mediafolderpath + @"\" + list_timestamps[0].ToString() + ".mpg";
                Capture tempcapture = new Capture(tempvideopath);
                fps = (int)tempcapture.GetCaptureProperty(CAP_PROP.CV_CAP_PROP_FPS);
                tempcapture.Dispose();
            }

            VideoWriter videowriter = new VideoWriter(videopath, codec, fps, 640, 480, true);
            

            for (int i = 0; i < list_timestamps.Count; i++)
            {
                videopath = Program.getConfiguration().Mediafolderpath + @"\" + list_timestamps[i].ToString() + ".mpg";
                try
                {
                    Capture joincapture = new Capture(videopath);
                    Image<Bgr, byte> frame = joincapture.QueryFrame();
                    for (int n = 1; n < 15; n++)
                        joincapture.QueryFrame();

                    while (frame != null)
                    {
                        videowriter.WriteFrame(frame);
                        frame = joincapture.QueryFrame();
                    }
                    joincapture.Dispose();

                    // Notify main frame to update its progressbar
                    ExportVideoProgressEventArgs e = new ExportVideoProgressEventArgs(i);
                    DoneAppendingRallyVideoEvent(this, e);
                }
                catch (NullReferenceException) { Console.WriteLine("unreadable video file"); }
            }
            videowriter.Dispose();
        
        }