open cv webcam

webcam.cpp

#include <stdio.h>
#include <fcntl.h>    /* For O_RDWR */
#include <sys/ioctl.h>
#include <unistd.h>   /* For open(), creat() */
#include <netdb.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <unistd.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <cuda_runtime.h>
#include <device_launch_parameters.h>
#include <time.h>
#include <stdint.h>
#include "opencv2/opencv.hpp"
#include <pthread.h>
#include "v4l.h"

#define NSTREAMS 1

using namespace cv;

int main() {

    VideoCapture cap;
    if (!cap.open(0, CAP_V4L2)) return 1;
    cap.set(3, 1920);
    cap.set(4, 1080);

    Mat base;
    cap >> base;

    namedWindow("hi", WINDOW_GUI_NORMAL);
    while (1) {

        auto begin = std::chrono::high_resolution_clock::now();

        cap >> base;
        if (base.empty()) {
            break;  // end of video stream
        }

        imshow("hi", base);
        if (waitKey(10) == 27) {
            break;  // stop capturing by pressing ESC
        }

        auto end = std::chrono::high_resolution_clock::now();
        auto elaps = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);

        printf("\rFPS: %5.2f", 1 / ((float)elaps.count() * 1e-9));
        fflush(stdout);
    }


    return 0;
}