network camera access

[denbja9]

I am trying to access a network camera, the address is definitely correct.
I have tried to modify the address string several times by adding and removing information, but I always get the following message:""Error opening video stream or file".
I am not understanding why this is happening since I am definitely connected to the camera.

#include <stdio.h>
#include <opencv2/opencv.hpp>
#include <iostream>

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


    

int main(int, char**) {
    cv::VideoCapture vcap;
    cv::Mat image;

    // This works on a D-Link CDS-932L
    const std::string videoStreamAddress = "http://some address/video.cgi?.mjpg";
       //open the video stream and make sure it's opened
    if(!vcap.open(videoStreamAddress)) {
        std::cout << "Error opening video stream or file" << std::endl;
        return -1;
    }

    for(;;) {
        if(!vcap.read(image)) {
            std::cout << "No frame" << std::endl;
            cv::waitKey();
        }
        cv::imshow("Output Window", image);

        if(cv::waitKey(1) >= 0) break;
    }   

}