Bare-bones C++ script for viewing gstreamer video from the CSI port of the Nvidia Jetson TX2.

gstreamer_view.cpp

/*
  Example code for displaying gstreamer video from the CSI port of the Nvidia Jetson in OpenCV.
  Created by Peter Moran on 7/29/17.
  https://gist.github.com/peter-moran/742998d893cd013edf6d0c86cc86ff7f
*/

#include <opencv2/opencv.hpp>

std::string get_tegra_pipeline(int width, int height, int fps) {
    return "nvcamerasrc ! video/x-raw(memory:NVMM), width=(int)" + std::to_string(width) + ", height=(int)" +
           std::to_string(height) + ", format=(string)I420, framerate=(fraction)" + std::to_string(fps) +
           "/1 ! nvvidconv flip-method=2 ! video/x-raw, format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink";
}

int main() {
    // Options
    WIDTH = 1920;
    HEIGHT = 1080;
    FPS = 30;

    // Define the gstream pipeline
    std::string pipeline = get_tegra_pipeline(WIDTH, HEIGHT, FPS);
    std::cout << "Using pipeline: \n\t" << pipeline << "\n";

    // Create OpenCV capture object, ensure it works.
    cv::VideoCapture cap(pipeline, cv::CAP_GSTREAMER);
    if (!cap.isOpened()) {
        std::cout << "Connection failed";
        return -1;
    }

    // View video
    cv::Mat frame;
    while (1) {
        cap >> frame;  // Get a new frame from camera

        // Display frame
        imshow("Display window", frame);
        cv::waitKey(1); //needed to show frame
    }
}

after adding declarations and command line args to build i was able to get the script to run but its not doing anything
im a newb

nvidia@tegra-ubuntu:~$ ./gstreamer_view
Using pipeline:
nvcamerasrc ! video/x-raw(memory:NVMM), width=(int)1920, height=(int)1080, format=(string)I420, framerate=(fraction)30/1 ! nvvidconv flip-method=2 ! video/x-raw, format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! appsink

But nothing happens.