VideoCapture类

#include <opencv2/core/core.hpp>#include <opencv2/highgui/highgui.hpp>#include <opencv2/imgproc/imgproc.hpp>#include <iostream>using namespace std;using namespace cv;int main(){    //打开视频文件：其实就是建立一个VideoCapture结构    VideoCapture capture("D:/videos/PetsD2TeC2.avi");    //检测是否正常打开:成功打开时，isOpened返回ture    if(!capture.isOpened())        cout<<"fail to open!"<<endl;    //获取整个帧数    long totalFrameNumber = capture.get(CV_CAP_PROP_FRAME_COUNT);    cout<<"整个视频共"<<totalFrameNumber<<"帧"<<endl;    //设置开始帧()    long frameToStart = 300;    capture.set( CV_CAP_PROP_POS_FRAMES,frameToStart);    cout<<"从第"<<frameToStart<<"帧开始读"<<endl;    //设置结束帧    int frameToStop = 400;    if(frameToStop < frameToStart)    {        cout<<"结束帧小于开始帧，程序错误，即将退出！"<<endl;        return -1;    }    else    {        cout<<"结束帧为：第"<<frameToStop<<"帧"<<endl;    }    //获取帧率    double rate = capture.get(CV_CAP_PROP_FPS);    cout<<"帧率为:"<<rate<<endl;    //定义一个用来控制读取视频循环结束的变量    bool stop = false;    //承载每一帧的图像    Mat frame;    //显示每一帧的窗口    namedWindow("Extracted frame");    //两帧间的间隔时间:    //int delay = 1000/rate;    int delay = 1000/rate;    //利用while循环读取帧    //currentFrame是在循环体中控制读取到指定的帧后循环结束的变量    long currentFrame = frameToStart;    //滤波器的核    int kernel_size = 3;    Mat kernel = Mat::ones(kernel_size,kernel_size,CV_32F)/(float)(kernel_size*kernel_size);    while(!stop)    {        //读取下一帧        if(!capture.read(frame))        {            cout<<"读取视频失败"<<endl;            return -1;          }        //这里加滤波程序        imshow("Extracted frame",frame);        filter2D(frame,frame,-1,kernel);        imshow("after filter",frame);        cout<<"正在读取第"<<currentFrame<<"帧"<<endl;        //waitKey(int delay=0)当delay ≤ 0时会永远等待；当delay>0时会等待delay毫秒        //当时间结束前没有按键按下时，返回值为-1；否则返回按键        int c = waitKey(delay);        //按下ESC或者到达指定的结束帧后退出读取视频        if((char) c == 27 || currentFrame > frameToStop)        {            stop = true;        }        //按下按键后会停留在当前帧，等待下一次按键        if( c >= 0)        {            waitKey(0);        }        currentFrame++;    }    //关闭视频文件    capture.release();    waitKey(0);    return 0;}