OpenCV读取MP4视频裁剪部分后写成AVI视频

// CropVideo.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "opencv.hpp"

using namespace cv;
using namespace std;

int main()
{
	VideoCapture cap("F:\\ImageLib\\10.mp4");
	if (cap.isOpened())
		cout << "Video " <<
		": width=" << cap.get(CAP_PROP_FRAME_WIDTH) <<
		", height=" << cap.get(CAP_PROP_FRAME_HEIGHT) <<
		", nframes=" << cap.get(CAP_PROP_FRAME_COUNT) << endl;
	double fps = cap.get(CAP_PROP_FPS);
	VideoWriter wri("F:\\ImageLib\\temp\\10.avi", VideoWriter::fourcc('M', 'J', 'P', 'G'), fps, Size(1080, 1440));
	while (1)
	{
		Mat frame;
		cap >> frame;
		if (frame.empty())
			break;
		Mat newFrame = frame(Rect(0, 240, 1080, 1440));
		wri << newFrame;
		//imshow("iopencv.com", frame);
		//waitKey(10);
	}
	cap.release();
	wri.release();
    return 0;
}