Opencv realizes opening camera and video files

This article will use opencv to open camera and video files.

Similar to opening a picture, the operation of a video is also very simple.

VideoCapture class: In opencv, the video is read and the camera is called through the VideoCapture class.

First, opencv open the camera

Code:

#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/videoio.hpp"
#include <iostream>

using namespace cv;
using namespace std;


intmain()
{
    cout << "Built with OpenCV " << CV_VERSION << endl;

	VideoCapture capture(0); // open the camera
	if(!capture.isOpened()) // determine whether the opening is successful
	{
		cout << "open camera failed. " << endl;
		return -1;
	}
	
	while(true)
	{
		Mat frame;
		capture >> frame; // read image frame to frame
		if(!frame.empty()) // determine whether it is empty
		{
			imshow("camera", frame);
		}
		
		if(waitKey(30) > 0) // delay 30 ms to wait for the key
		{
			break;
		}
	}

    return 0;
}

Compile and run:

Second, opencv to open the video file

Code:

#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/videoio.hpp"
#include <iostream>

using namespace cv;
using namespace std;


intmain()
{
    cout << "Built with OpenCV " << CV_VERSION << endl;

	VideoCapture video;
	video.open("video.avi"); // open video file

	if(!video.isOpened()) // Determine whether the opening is successful
	{
		cout << "open video file failed. " << endl;
		return -1;
	}
	
	while(true)
	{
		Mat frame;
		video >> frame; // read image frame to frame
		if(!frame.empty()) // Is the frame empty
		{
			imshow("video", frame); // show the image
		}

		if(waitKey(30) > 0) // delay 30 ms to wait for a key
		{
			break;
		}
	}

    return 0;
}

Compile and run:

So far, the simple use of opencv to open the camera and video files has been completed.