opencv中通过VideoCaptrue类对视频进行读取操作以及调用摄像头.常用的操作如下:

1、常用构造函数

1.VideoCapture类的构造函数：
C++: VideoCapture::VideoCapture()
C++: VideoCapture::VideoCapture(const string& filename)
C++: VideoCapture::VideoCapture(int device)

2、判断是否打开

cap.isOpened()

3、获取视频相关属性

cout << "视频相关信息如下" << endl;
cout << "宽度：" << cap.get(CV_CAP_PROP_FRAME_WIDTH) << endl;
cout << "高度：" << cap.get(CV_CAP_PROP_FRAME_HEIGHT) << endl;

cout << "总帧数：" << cap.get(CV_CAP_PROP_FRAME_COUNT) << endl;
cout << "帧率（fps）：" << cap.get(CV_CAP_PROP_FPS) << endl;

4、逐帧读取

Mat frame;

cap >> frame;

5、判断是否完毕

frame.empty()

6、显示视频

imshow("readvideo", frame);

 1 include <opencv2\opencv.hpp>
 2 #include <iostream>
 3 using namespace std;
 4 using namespace cv;
 5 int main()
 6 {
 7     cout <<CV_VERSION << endl;
 8     VideoCapture cap("c://dev//res//out.avi");
 9     if (!cap.isOpened())
10     {
11         cout << "视频文件打开失败" << endl;
12     }
13     cout << "视频相关信息如下" << endl;
14     cout << "宽度：" << cap.get(CV_CAP_PROP_FRAME_WIDTH) << endl;
15     cout << "高度：" << cap.get(CV_CAP_PROP_FRAME_HEIGHT) << endl;
16     cout << "总帧数：" << cap.get(CV_CAP_PROP_FRAME_COUNT) << endl;
17     cout << "帧率（fps）：" << cap.get(CV_CAP_PROP_FPS) << endl;
18 
19     Mat frame;
20     while (1)
21     {
22         cap >> frame;
23         if (frame.empty())
24         {
25             break;
26         }
27         imshow("readvideo", frame);
28         waitKey(20);//win10 vs2015返回值-1
29     }
30     getchar();
31     return 0;