【轉】OpenCV的C++版本播放視頻的綜合例子

#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()
{
    //打開視頻文件：其實就是建立一個VideoCapture結構
    VideoCapture capture("D:/videos/PetsD2TeC2.avi");
    //檢測是否正常打開:成功打開時，isOpened返回ture
    if(!capture.isOpened())
        cout<<"fail to open!"<<endl;
    //獲取整個幀數
    long totalFrameNumber = capture.get(CV_CAP_PROP_FRAME_COUNT);
    cout<<"整個視頻共"<<totalFrameNumber<<"幀"<<endl;


    //設置開始幀()
    long frameToStart = 300;
    capture.set( CV_CAP_PROP_POS_FRAMES,frameToStart);
    cout<<"從第"<<frameToStart<<"幀開始讀"<<endl;


    //設置結束幀
    int frameToStop = 400;

    if(frameToStop < frameToStart)
    {
        cout<<"結束幀小於開始幀，程序錯誤，即將退出！"<<endl;
        return -1;
    }
    else
    {
        cout<<"結束幀為：第"<<frameToStop<<"幀"<<endl;
    }


    //獲取幀率
    double rate = capture.get(CV_CAP_PROP_FPS);
    cout<<"幀率為:"<<rate<<endl;



    //定義一個用來控制讀取視頻循環結束的變量
    bool stop = false;
    //承載每一幀的圖像
    Mat frame;
    //顯示每一幀的窗口
    namedWindow("Extracted frame");
    //兩幀間的間隔時間:
    //int delay = 1000/rate;
    int delay = 1000/rate;


    //利用while循環讀取幀
    //currentFrame是在循環體中控制讀取到指定的幀后循環結束的變量
    long currentFrame = frameToStart;


    //濾波器的核
    int kernel_size = 3;
    Mat kernel = Mat::ones(kernel_size,kernel_size,CV_32F)/(float)(kernel_size*kernel_size);

    while(!stop)
    {
        //讀取下一幀
        if(!capture.read(frame))
        {
            cout<<"讀取視頻失敗"<<endl;
            return -1;    
        }
        
        //這里加濾波程序
        imshow("Extracted frame",frame);
        filter2D(frame,frame,-1,kernel);

        imshow("after filter",frame);
        cout<<"正在讀取第"<<currentFrame<<"幀"<<endl;
        //waitKey(int delay=0)當delay ≤ 0時會永遠等待；當delay>0時會等待delay毫秒
        //當時間結束前沒有按鍵按下時，返回值為-1；否則返回按鍵


        int c = waitKey(delay);
        //按下ESC或者到達指定的結束幀后退出讀取視頻
        if((char) c == 27 || currentFrame > frameToStop)
        {
            stop = true;
        }
        //按下按鍵后會停留在當前幀，等待下一次按鍵
        if( c >= 0)
        {
            waitKey(0);
        }
        currentFrame++;
    
    }
    //關閉視頻文件
    capture.release();
    waitKey(0);
    return 0;
}