Jetson CUDA Code

#include <iostream>
#include <ctime>
#include <cmath>


#include <opencv2/core.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/imgcodecs.hpp>

#include <opencv2/core/cuda.hpp>
#include <opencv2/cudaimgproc.hpp>
#include <opencv2/cudawarping.hpp>
#include <opencv2/cudaarithm.hpp>


std::string gstreamer_pipeline (int capture_width, int capture_height, int display_width, int display_height, int framerate, int flip_method) {
return "nvarguscamerasrc ! video/x-raw(memory:NVMM), width=(int)" + std::to_string(capture_width) + ", height=(int)" +
        std::to_string(capture_height) + ", format=(string)NV12, framerate=(fraction)" + std::to_string(framerate) +
        "/1 ! nvvidconv flip-method=" + std::to_string(flip_method) + " ! video/x-raw, width=(int)" + std::to_string(display_width) + ", height=(int)" +
        std::to_string(display_height) + ", format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink";
}

int main()
{
    cv::cuda::printCudaDeviceInfo(cv::cuda::getDevice());

    int capture_width = 1280 ;
    int capture_height = 720 ;
    int display_width = 1280 ;
    int display_height = 720 ;
    int framerate = 60 ;
    int flip_method = 2 ;

    std::string pipeline = gstreamer_pipeline(capture_width,
    capture_height,
    display_width,
    display_height,
    framerate,
    flip_method);
    std::cout << "Using pipeline: \n\t" << pipeline << "\n";

    cv::VideoCapture cap(pipeline, cv::CAP_GSTREAMER);
    if(!cap.isOpened()) {
    std::cout<<"Failed to open camera."<<std::endl;
    return (-1);
    }

    cv::namedWindow("CSI Camera", cv::WINDOW_AUTOSIZE);
    cv::Mat img;

    std::cout << "Hit ESC to exit" << "\n" ;
    while(true)
    {
        if (!cap.read(img)) {
        std::cout<<"Capture read error"<<std::endl;
        break;
    }
    cv::cuda::GpuMat display, smaller;
    display.upload(img);

    cv::cuda::resize(display, smaller, cv::Size(1920,1080));

    display.download(img);

    cv::imshow("CSI Camera",img);
    int keycode = cv::waitKey(5) & 0xff ;
        if (keycode == 27) break ;
    }

    cap.release();
    cv::destroyAllWindows() ;
    return 0;
}