C++ VideoCapture::release方法代码示例

bool
openCaptureDevice(VideoCapture &reader, int dev)
{
    bool opened = false;
    try
    {
        if (!reader.isOpened())
        {
            std::cout << "\nTrying to open device:\n " << dev << "\n";
            opened = reader.open(dev);
        }
    } catch (...)
    {
        std::cerr << "Stopping search. Cam not detected with input:\n " << dev
                  << "\n";
        reader.release();
        opened = false;
    }

    if (!opened)
    {
        reader.release();
    }

    return opened;
};

/*
This function handles the releasing of objects when this node is
requested or forced (via CTRL+C) to shutdown.
*/
void onShutdown(int sig){
	destroyWindow(CVWINDOW);
	cap1.release();
	cap2.release();
	cap3.release();
	ROS_INFO("All objects should have been released, proper shutdown complete");
	ros::shutdown();
}

void my_handler(int s)
{
    printf("Caught signal %d\n", s);
    control.stop();
    cap.release();
    exit(1);
}

//==============================================================================
int main(int argc,char** argv)
{
	//parse command line arguments
	if(argc < 2){cout << usage << endl; return 0;}
	if(parse_help(argc,argv)){cout << usage << endl; return 0;}
	
	//load detector model
	face_detector detector = load_ft<face_detector>(argv[1]);

	//open video stream
	VideoCapture cam; 
	if(argc > 2)cam.open(argv[2]); else cam.open(0);
	if(!cam.isOpened()){
		cout << "Failed opening video file." << endl
		 << usage << endl; return 0;
	}
	//detect until user quits
	namedWindow("face detector");
	while(cam.get(CV_CAP_PROP_POS_AVI_RATIO) < 0.999999){
		Mat im; cam >> im;     
		vector<Point2f> p = detector.detect(im);
		if(p.size() > 0){
			for(int i = 0; i < int(p.size()); i++)
		circle(im,p[i],1,CV_RGB(0,255,0),2,CV_AA);
		}
		imshow("face detector",im);
		if(waitKey(10) == 'q')break;
	}
	destroyWindow("face detector"); cam.release(); return 0;
}

    JNIEXPORT void JNICALL Java_org_opencv_highgui_VideoCapture_n_1release
    (JNIEnv* env, jclass, jlong self)
    {
        try {
#ifdef DEBUG
            LOGD("highgui::VideoCapture_n_1release()");
#endif // DEBUG
            VideoCapture* me = (VideoCapture*) self; //TODO: check for NULL
            me->release(  );

            return;
        } catch(cv::Exception e) {
#ifdef DEBUG
            LOGD("highgui::VideoCapture_n_1release() catched cv::Exception: %s", e.what());
#endif // DEBUG
            jclass je = env->FindClass("org/opencv/core/CvException");
            if(!je) je = env->FindClass("java/lang/Exception");
            env->ThrowNew(je, e.what());
            return;
        } catch (...) {
#ifdef DEBUG
            LOGD("highgui::VideoCapture_n_1release() catched unknown exception (...)");
#endif // DEBUG
            jclass je = env->FindClass("java/lang/Exception");
            env->ThrowNew(je, "Unknown exception in JNI code {highgui::VideoCapture_n_1release()}");
            return;
        }
    }

int processVideo(VideoCapture& capture) {
    if(!capture.isOpened()){
        //error in opening the video input
        exit(EXIT_FAILURE);
    }
    Ptr<BackgroundSubtractor> pMOG2 = createBackgroundSubtractorMOG2(); //MOG2 approach
    //read input data. ESC or 'q' for quitting
    while( (char)keyboard != 'q' && (char)keyboard != 27 ){
        //read the current frame
        if(!capture.read(frame)) {
            cerr << "Unable to read next frame." << endl;
            cerr << "Exiting..." << endl;
            exit(EXIT_FAILURE);
        }
        //update the background model
        pMOG2->apply(frame, fgMaskMOG2,-2);
        //get the frame number and write it on the current frame
        stringstream ss;
        rectangle(frame, cv::Point(10, 2), cv::Point(100,20),
                cv::Scalar(140,89,255), -1);
        ss << capture.get(CAP_PROP_POS_FRAMES);
        string frameNumberString = ss.str();
        putText(frame, frameNumberString.c_str(), cv::Point(15, 15),
                FONT_HERSHEY_SIMPLEX, 0.5 , cv::Scalar(0,0,0));
        //show the current frame and the fg masks
        imshow("Frame", frame);
        imshow("FG Mask MOG 2", fgMaskMOG2);
        //get the input from the keyboard
        keyboard = waitKey( 30 );
    }
    //delete capture object
    capture.release();
    return 0;
}

int main()
{

  int key;

  VideoCapture webcam;
  webcam.open(0);

  Mat img;


  while(webcam.read(img))
  {
      imshow("WEbcam",img);

      key=cvWaitKey(10);  //wait   upto10 sec for next key stroke

      if(key==27)
         break;   // if user press escape (ESC) key then video capturing stops and last frame will be saved.
  }

  /*saving image*/
  imwrite("image.jpg",img);
  webcam.release();


  /*Re-display image*/
  Mat img2=imread("image.jpg");
  imshow("Taken Image",img2);
  cvWaitKey(0);

  return 0;
}

int main(int argc, char * argv[]){
  VideoCapture cam;
 //Read options
  CommandLineParser parser(argc, argv, keys);
  string video = parser.get<string>("v");
  int f0 = parser.get<int>("i");
  //Init cam
  if (video != "null")
    cam.open(video);
  else
    cam.open(0);
  if (!cam.isOpened()){
	  cout << "cam device failed to open!" << endl;
    return 1;
  }
  //Read first frame
  Mat frame;
  cam.set(CV_CAP_PROP_POS_FRAMES,f0);
  cam.read(frame);
  while(cam.read(frame)){
  	//Display
    imshow("Player", frame);
    char key = cvWaitKey(33);
    if (key == 'q')
      break;
  }
  cam.release();
  return 0;
}

/**
 * this function provides a way to exit nicely from the system
 */
void quit(string msg, int retval)
{
    if (retval == 0) {
        cout << (msg == "NULL" ? "" : msg) << "\n" << endl;
    } else {
        cerr << (msg == "NULL" ? "" : msg) << "\n" << endl;
    }
    if (clientSock){
        close(clientSock);
    }
    if (capture.isOpened()){
        capture.release();
    }
    if (!(img0.empty())){
        (~img0);
    }
    if (!(img1.empty())){
        (~img1);
    }
    if (!(img2.empty())){
        (~img2);
    }
    pthread_mutex_destroy(&gmutex);
    exit(retval);
}

void video_thread_CL(void* pParams)
{
	FaceDetector *faceDetector;
	if (threadUseCL){
		faceDetector = (FaceDetectorCL*)pParams;
	}
	else{
		faceDetector = (FaceDetectorCpu*)pParams;
	}
	
	std::string name = faceDetector->name();

	//HAAR_EYE_TREE_EYEGLASSES_DATA
	//HAAR_EYE_DATA
	//HAAR_FRONT_FACE_DEFAULT_DATA
	//LBP_FRONTAL_FACE
	//LBP_PROFILE_FACE
	faceDetector->load(HAAR_FRONT_FACE_DEFAULT_DATA);

	VideoCapture videoCapture;
	cv::Mat frame, frameCopy, image;

	videoCapture.open(faceDetector->videoFile().c_str());
	if (!videoCapture.isOpened()) { cout << "No video detected" << endl; return; }

	if (imshowFlag) { cv::namedWindow(name.c_str(), 1); }

	if (videoCapture.isOpened())
	{
		cout << "In capture ..." << name.c_str() << endl;
		while (videoCapture.grab())
		{
			if (!videoCapture.retrieve(frame, 0)) { break; }

			faceDetector->setSrcImg(frame, 1);
			faceDetector->doWork();
			if (imshowFlag){ cv::imshow(name.c_str(), faceDetector->resultMat()); }
			
			std::vector<cv::Rect> &faces_result = faceDetector->getResultFaces();
			std::cout << "face --" << name.c_str() << std::endl;
			for (int i = 0; i < faces_result.size(); ++i){
				std::cout << faces_result.at(i).x << ", " << faces_result.at(i).y << std::endl;
			}
			
			if (waitKey(10) >= 0){
				videoCapture.release();
				break;
			}

			Sleep(1);
		}
	}
	
	if (imshowFlag) { cvDestroyWindow(name.c_str()); }
	finishTaskFlag++;
	_endthread();
	return;

}

VOID inline GlobalExits(VOID)
{
	g_writer.release();
	g_cap.release();
	g_captureStat = capture_IDLE;
	SecureEndThread(threadStat);
	cv::destroyAllWindows();
	g_runningONE = FALSE;
}

	void unload() {
		if(cap != NULL) {
			if(cap->isOpened()) {
				cap->release();
			}
			delete cap;
			cap = NULL;
		}
	}

int main(int argc, char *argv[])
{
    start_fps();
    sleep(1);

    /*********************PARAMETROS*****************/  
    if(argc<2) 
    {   
        Cwarning;
        printf("Nenhum argumento adicionado ao programa\n");
        Cwarning;
        printf("Por default o programa ira selecionar o maior ID de camera\n");

        int idCamera=3;
        
        cap.open(idCamera);
        while(!cap.isOpened()) 
        {

            Cerro;
            printf("Erro ao abrir a camera id %d!\n",idCamera);
            idCamera--;
            if(idCamera==-1)
                return -1;
            cap.release();
            cap.open(idCamera);
        }
        sleep(1);
    }
    else
    {
        char *local_video;      
        local_video=argv[1];
        Cok;
        printf("Video ! %s ! escolhido pelo usuario\n",local_video);
        cap.open(local_video);
        if(!cap.isOpened())
        {
            Cerro;
            printf("Arquivo nao encontrado !\n");
            return -1;
        }
        sleep(1);
    }
    /************************************************/ 

    pthread_t get_img;
    pthread_t show_img;

    pthread_create(&get_img, NULL, streaming , NULL); //pega imagem da camera ou do arquivo
    pthread_create(&show_img, NULL, image_show , NULL); //pega imagem da camera ou do arquivo

    pthread_join(get_img,NULL); 
    pthread_join(show_img,NULL); 


}

extern "C" JNIEXPORT void JNICALL Java_narl_itrc_vision_CapVidcap_implDone(
	JNIEnv* env,
	jobject thiz
){
	PREPARE_CONTEXT;

	VideoCapture* vid = (VideoCapture*)(cntx);
	vid->release();
	delete vid;
}

int main( int argc, char* argv[] )
{
	if(argc > 2)
		NOWRITE = 0;
	cout << "nowrite = " << NOWRITE << endl;
	namedWindow( "Example2_10", CV_WINDOW_AUTOSIZE );
	namedWindow( "Log_Polar", CV_WINDOW_AUTOSIZE );
	Mat bgr_frame;
	VideoCapture capture;
	if( argc < 2 || !capture.open( argv[1] ) ){
		help();
		cout << "Failed to open " << argv[1] << "\n" << endl;
		return -1;
	}

	double fps = capture.get(CV_CAP_PROP_FPS);
	cout << "fps = " << fps << endl;
	Size size((int)capture.get(CV_CAP_PROP_FRAME_WIDTH),
			(int)capture.get(CV_CAP_PROP_FRAME_HEIGHT));
	cout << " frame (w, h) = (" << size.width << ", " << size.height << ")" <<endl;
	VideoWriter writer;
	if(! NOWRITE)
	{ writer.open(  // On linux Will only work if you've installed ffmpeg development files correctly,
			argv[2],                               // otherwise segmentation fault.  Windows probably better.
			CV_FOURCC('M','J','P','G'),
			fps,
			size
	);
	}
	Mat logpolar_frame(size,CV_8UC3);
	Mat gray_frame(size,CV_8UC1);

	for(;;) {
		capture >> bgr_frame;
		if( bgr_frame.empty() ) break;
		imshow( "Example2_10", bgr_frame );
		cvtColor(   //We never make use of this gray image
				bgr_frame, gray_frame, CV_BGR2GRAY);
		IplImage lp = logpolar_frame;
		IplImage bgrf = bgr_frame;
		cvLogPolar( &bgrf, &lp,  //This is just a fun conversion the mimic's the human visual system
				cvPoint2D32f(bgr_frame.cols/2,
						bgr_frame.rows/2),
						40,
						CV_WARP_FILL_OUTLIERS );
		imshow( "Log_Polar", logpolar_frame );
		//Sigh, on linux, depending on your ffmpeg, this often won't work ...
		if(! NOWRITE)
			writer << logpolar_frame;
		char c = waitKey(10);
		if( c == 27 ) break;
	}

	capture.release();
}