java opencv通过rtsp获取视频流，保存视频到本地

• 代码都是来自网络，收集的比较乱，所有找不到出处了。
  获取视频流的核心代码
  private static void testRtsp() {
      //必须要加入这两个东西
      System.load("D:\\opencv-4.1.1\\opencv\\build\\x64\\vc15\\bin\\opencv_world411.dll");
      System.load("D:\\opencv-4.1.1\\opencv\\build\\bin\\opencv_videoio_ffmpeg411_64.dll");
      VideoCapture vc = new VideoCapture();
      boolean isOpen = vc.open("rtsp://admin:admin@192.168.88.250");
  
      System.out.println("isOpen="+isOpen);
  
      Mat mat = new Mat();
      String winName = "showFrame";
      int height = 600,width = 800;
      HighGui.namedWindow(winName);
      HighGui.resizeWindow(winName, width, height);
      while(vc.read(mat)){
          // 重置大小
          Mat dst = new Mat();
          Imgproc.resize(mat, dst, new Size(width,height));
          // 显示
          HighGui.imshow(winName, dst);
          // waitkey 必须要，否则无法显示
          int key = HighGui.waitKey(1);
          System.out.println("key="+key);
          //esc键退出
          if(key == 27){
              break;