void processVideo(char* videoFilename) {   Mat frame; // current frame   Mat fgMaskMOG2; // fg mask fg mask generated by MOG2 method   Mat bgImg; // background   Ptr<BackgroundSubtractorMOG2> pMOG2 = createBackgroundSubtractorMOG2(200, 36.0, false); // MOG2 Background subtractor    while (true)   {     VideoCapture capture(videoFilename);     if (!capture.isOpened())     {       cerr << "Unable to open video file: " << videoFilename << endl;       return;     }      int width = (int)capture.get(CV_CAP_PROP_FRAME_WIDTH);     int height = (int)capture.get(CV_CAP_PROP_FRAME_HEIGHT);      unique_ptr<IplImage, void(*)(IplImage*)> labelImg(cvCreateImage(cvSize(width, height), IPL_DEPTH_LABEL, 1),        [](IplImage* p){ cvReleaseImage(&p); });     CvBlobs blobs;     CvTracks tracks;      while (true)     {       // read input data. ESC or 'q' for quitting       int key = waitKey(1);       if (key == 'q' || key == 27)         return;       if (!capture.read(frame))         break;        // update background       pMOG2->apply(frame, fgMaskMOG2);       pMOG2->getBackgroundImage(bgImg);       imshow("BG", bgImg);       imshow("Original mask", fgMaskMOG2);        // post process       medianBlur(fgMaskMOG2, fgMaskMOG2, 5);       imshow("medianBlur", fgMaskMOG2);       morphologyEx(fgMaskMOG2, fgMaskMOG2, MORPH_CLOSE, getStructuringElement(MORPH_RECT, Size(5, 5))); // fill black holes       morphologyEx(fgMaskMOG2, fgMaskMOG2, MORPH_OPEN, getStructuringElement(MORPH_RECT, Size(5, 5))); // fill white holes       imshow("morphologyEx", fgMaskMOG2);        // track       cvLabel(&IplImage(fgMaskMOG2), labelImg.get(), blobs);       cvFilterByArea(blobs, 64, 10000);       cvUpdateTracks(blobs, tracks, 10, 90, 30);       cvRenderTracks(tracks, &IplImage(frame), &IplImage(frame));        // show       imshow("Frame", frame);        key = waitKey(30);     }   } }