NVIDIA Jetson Nano - [ WARN:0] global


When I reinstall system from my ISO Jetson Nano backup I get this error after running code from tutorial NVIDIA OpenCV and video from cars.mp4 not displayed.

[ WARN:0] global /home/nvidia/opencv/modules/videoio/src/cap_gstreamer.cpp (711) open OpenCV | GStreamer warning: Error opening bin: unexpected reference "cars" - ignoring
[ WARN:0] global /home/nvidia/opencv/modules/videoio/src/cap_gstreamer.cpp (480) isPipelinePlaying OpenCV | GStreamer warning: GStreamer: pipeline have not been created

This is code:
#include <opencv2/opencv.hpp>
#include “opencv2/core.hpp”
#include “opencv2/imgproc.hpp”
#include “opencv2/highgui.hpp”
#include <opencv2/videoio.hpp>
#include <opencv2/features2d.hpp>

int main()
	cv::VideoCapture input("cars.mp4");	
	cv::Mat img, img_prev;
	std::vector<cv::Point2f> points, points_prev;
	std::vector<uchar> status;
	std::vector<float> error;
	cv::Ptr<cv::ORB> detector = cv::ORB::create();
	std::vector<cv::KeyPoint> keypoints;
	detector->detect(img, keypoints, cv::Mat());
	cv::KeyPoint::convert(keypoints, points);
	points_prev = points;

	for (;;)
		if (!input.read(img))

			img_prev, img,
			points_prev, points,
			status, error);


		for(size_t i=0; i<points.size(); i++)
			cv::circle(img, points[i], 3,
				cv::Scalar(0, 0, cv::norm(points_prev[i] - points[i]) * 20), 3);

		points_prev = points;

		cv::imshow("img", img);
		char c = cv::waitKey();

		if (c == 27)	//27 is ESC

I don’t get error when I build code by cmake. However CUDA example works.

Anybody have idea what I made wrong?

I made reinstall system from backup because I unfortunately upgrade ubuntu to 20.04 version.

Greetings from Poland,

I can’t help on the OpenCV, but you might find this useful on tricking SDK Manager into working on an Ubuntu 20.04 host PC:
(it is a bit old, but the idea is to make 20.04 look like 18.04 when installing content to the Jetson…don’t think it will help for installing content to the host PC)