opencv VideoCapture使用示例

在centos7下验证VideoCapture功能。

1 opencv处理视频时要使用ffmpeg，这里使用添加源的方式安装，分为3步

1.1 先安装EPEL Release，使用其他的repo源，所以需要EPEL支持
yum install -y epel-release
#如果出现缺少Code提示，可以：
sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
#安装完成之后，可以查看是否安装成功
yum repolist

1.2 安装Nux-Dextop源

#导入一个Code
sudo rpm --import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro
#安装nux-dextop 源
sudo rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-1.el7.nux.noarch.rpm
#查看repo源是否安装成功
yum repolist

1.3 yum安装ffmpeg
yum install -y ffmpeg
yum install -y ffmpeg-dev

2 还要安装gtk库

yum install gtk+-devel gtk2-devel

3 此时可以编译opevcv源码，在源码根目录下建立一个build目录，进入build目录执行

cmake ..

make

make install

到此处安装完成

4 验证程序

摄像头

    #include <opencv2/opencv.hpp>      #include <iostream>            int main()      {          cv::VideoCapture capture;          capture.open(0);//open 根据编号打开摄像头        std::cout<<"-------------"<<std::endl;        if (!capture.isOpened())          {              std::cout << "Read video Failed !" << std::endl;              return 0;          }                cv::Mat frame;          cv::namedWindow("video test");                int frame_num = 800;              for (int i = 0; i < frame_num - 1; ++i)          {              capture >> frame;              //capture.read(frame);            imshow("video test", frame);              if (cv::waitKey(30) == 'q')              {                  break;              }          }                cv::destroyWindow("video test");          capture.release();          return 0;      }

本地文件

    #include <opencv2/opencv.hpp>  
    #include <iostream>  
      
    int main()  
    {  
        cv::VideoCapture capture;  
        capture.open("test.mp4");
        std::cout<<"-------------"<<std::endl;
        if (!capture.isOpened())  
        {  
            std::cout << "Read video Failed !" << std::endl;  
            return 0;  
        }  
      
        cv::Mat frame;  
        cv::namedWindow("video test");  
      
        capture.get(cv::CAP_PROP_FRAME_COUNT);  
        std::cout << "total frame number is: " << frame_num << std::endl;  
      
        for (int i = 0; i < frame_num - 1; ++i)  
        {  
            capture >> frame;  
            //capture.read(frame);
            imshow("video test", frame);  
            if (cv::waitKey(30) == 'q')  
            {  
                break;  
            }  
        }  
      
        cv::destroyWindow("video test");  
        capture.release();  
        return 0;  
    }

5 说明

运行时出现

Unable to stop the stream: Inappropriate ioctl for device

是因为没有安装ffmpeg-dev导致。

不能播放时确认是否安装yum install gtk+-devel gtk2-devel

来源：https://www.cnblogs.com/mingzhang/p/7460465.html

标签

OpenCV

capture