opencv 打开摄像头并将视频数据写入文件

cv::VideoCapture capture;
capture.open(0);
if (!capture.isOpened())
{
return;
}

string strPath = "c:\\test.avi";
cv::Mat frame;
cv::VideoWriter writer;
writer.open(strPath.c_str(), CV_FOURCC('M', 'J', 'P', 'G'), 25, cv::Size(640, 480), true);

while (true)
{
capture >> frame;
writer.write(frame);
cv::imshow("Video", frame);
char key = cv::waitKey(50);
if (key == 's') break;

}
writer.release();
capture.release();