OpenCV视频解单帧例子

主要利用VideoCapture类。

/* * 视频解单帧 */#include <iostream>#include <string>#include <unistd.h>#include <stdlib.h>#include <dirent.h>#include <opencv2/core/core.hpp>#include <opencv2/highgui/highgui.hpp>#include <opencv2/imgproc/imgproc.hpp>using namespace std;using namespace cv;int trackbarPosition;VideoCapture capture;bool isFileExist(const char *filePath){    if (filePath == NULL)        return false;    else if (access(filePath, F_OK) == 0)        return true;    else        return false;}bool isDirExist(const char *dirPath){    if (dirPath == NULL || opendir(dirPath) == NULL)        return false;    else        return true;}void setFramePosition(int position, void *){    capture.set(CV_CAP_PROP_POS_FRAMES, position);    trackbarPosition = position;}int main(){    const string videoName = "/home/corfox/Data/GOPR0451_removefisheye.mp4";    const string outputPath = "/home/corfox/Data/GOPR";    int frameNum = 1;    ostringstream numToStr;    string frameName;    Mat frame;    double frameScale = 0.5;    // 视频缩放因子    capture.open(videoName);    if (!capture.isOpened())        return 1;    const string windowName = "uncompress video";    const string trackbarName = "position";    namedWindow(windowName);    int frameNums = capture.get(CV_CAP_PROP_FRAME_COUNT);    if (frameNums >= 0)        createTrackbar(trackbarName, windowName, &trackbarPosition, frameNums, setFramePosition);    bool stop = false;    int selectIndex = -1;    int subDirName = 1;         // 创建的子文件夹名    int flag;    int frameWidth = capture.get(CV_CAP_PROP_FRAME_WIDTH) * frameScale;    int frameHight = capture.get(CV_CAP_PROP_FRAME_HEIGHT) * frameScale;    while(!stop)    {        if (!capture.read(frame))            break;        resize(frame, frame, Size(frameWidth, frameHight));        trackbarPosition++;        setTrackbarPos(trackbarName, windowName, trackbarPosition);        imshow(windowName, frame);        flag = waitKey(10);        if (flag == 27) // ESC            stop = true;        else if (flag == 115 || flag == 83) // 's' or 'S'        {            selectIndex = 0;            cout << "You pressed the key of 's' to save frame." << endl;        }        else if (flag == 101 || flag == 69) // 'e' or 'E'        {            selectIndex = 1;            cout << "You pressed the key of 'e' to stop saving frame." << endl;        }        else if (flag == 109 || flag == 77) // 'm' or 'M', to mkdir        {            string dirName;            numToStr << outputPath << "/" << subDirName;            dirName = numToStr.str();            if (!isDirExist(dirName.c_str()))            {                dirName = "mkdir " + dirName;                system(dirName.c_str());            }            frameNum = 1;            subDirName++;            numToStr.str("");            cout << "You pressed the key of 'm' to make a directory named the incremental digit number (1, 2, ...)." << endl;        }        switch (selectIndex) {        case 0:            numToStr << outputPath << "/" << (subDirName - 1) << "/" << frameNum << ".jpg";            frameName = numToStr.str();            frameNum++;            imwrite(frameName, frame);            numToStr.str("");            frameName.clear();            break;        case 1:            selectIndex = -1;            break;        default:            break;        }        frame.release();    }    capture.release();    return 0;}