OpenCV加载视频

//视频路径
  QString appPath = QCoreApplication::applicationDirPath();
  QString videoPath = appPath + "/vtest.avi";
  cv::VideoCapture capture;
  capture.open(videoPath.toStdString(),CAP_FFMPEG);
  //从摄像头读取
  //capture.open(0, CAP_DSHOW);
  cv::Mat frame;
  while (true) {
    //读帧
    bool ret = capture.read(frame);
    if (!ret)
      break;
    imshow("frame", frame);
    //添加帧处理 等待 100 毫秒，检查用户是否按下键盘上的按键
    char c = waitKey(100);
    //按下的是 ESC 键 (ASCII 值为 27)，则跳出循环，停止播放视频
    if (c == 27)
      break;
  }
  waitKey(0);
  destroyAllWindows();

//视频路径
  QString appPath = QCoreApplication::applicationDirPath();
  QString videoPath = appPath + "/vtest.avi";
  cv::VideoCapture capture;
  capture.open(videoPath.toStdString(),CAP_FFMPEG);
  qDebug() << u8"高：" << capture.get(CAP_PROP_FRAME_HEIGHT);
  qDebug() << u8"宽：" << capture.get(CAP_PROP_FRAME_WIDTH);
  qDebug() << u8"帧率FPS：" << QString::number(capture.get(CAP_PROP_FPS));
  qDebug() << u8"总帧率：" << capture.get(CAP_PROP_FRAME_COUNT);

//视频路径
  QString appPath = QCoreApplication::applicationDirPath();
  QString videoPath = appPath + "/vtest.avi";
  cv::VideoCapture capture;
  capture.open(videoPath.toStdString(), CAP_FFMPEG);
  qDebug() << u8"高：" << capture.get(CAP_PROP_FRAME_HEIGHT);
  qDebug() << u8"宽：" << capture.get(CAP_PROP_FRAME_WIDTH);
  qDebug() << u8"帧率FPS：" << capture.get(CAP_PROP_FPS);
  qDebug() << u8"总帧率：" << capture.get(CAP_PROP_FRAME_COUNT);
  //保存视频路径
  QString savevideoPath = appPath + "/output.avi";
  cv::VideoWriter writer(savevideoPath.toStdString(), capture.get(CAP_PROP_FOURCC), capture.get(CAP_PROP_FPS), Size(capture.get(CAP_PROP_FRAME_WIDTH), capture.get(CAP_PROP_FRAME_HEIGHT)));
  cv::Mat frame;
  while (true) {
    //读帧
    bool ret = capture.read(frame);
    if (!ret)
      break;
    imshow("frame", frame);
    //添加帧处理 
    writer.write(frame);
    //等待 100 毫秒，检查用户是否按下键盘上的按键
    char c = waitKey(100);
    //按下的是 ESC 键 (ASCII 值为 27)，则跳出循环，停止播放视频
    if (c == 27)
      break;
  }
  capture.release();
  writer.release();
  waitKey(0);
  destroyAllWindows();