streaming mjpg video to opencv: from android IP Webcam to cygwin64+ffmpeg+opencv

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Hello,

I am trying to process a MJPG stream from Android phone streaming with IP Webcam to Windows 7 Cygwin+ffmpeg+openv built following (http://hvrl.ics.keio.ac.jp/kimura/opencv/).

Please note from same PC both the following work: 1) VLC open network stream: http://192.168.0.241:8080/video?x.mjpg --> I see my video 2) ffmpeg -i http://192.168.0.241:8080/video?x.mjpg tmp.avi --> codes video to tmp.avi

Using opencv, I can compile with

g++ -o ipwebcam.exe ipwebcam.cpp `pkg-config --cflags --libs opencv`

and run below code but when I run it I get:

$ ./ipwebcam
[tcp @ 0x60001aba0] Failed to resolve hostname 192.168.0.241: Unknown error
Cannot open the video cam

Note that if I use cap.open("tmp.avi") it works. This seems to indicate ffmpeg somehow works!?!?

Browsing code, it seems issue is with libavformat in ffmpeg but I cannot fix it.

Can anybody help and indicate how to solve? I cannot believe that it is not possible to open a network stream with opencv and cygwin... :(

Cheers, AaWnSD

quote ipwecam.cpp

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

using namespace cv;
using namespace std;

int main(int argc, char* argv[])
{
    VideoCapture cap; //

    cap.open("http://192.168.0.241:8080/video?x.mjpg");

    if (!cap.isOpened())  // if not success, exit program
    {
        cout << "Cannot open the video cam" << endl;
        return -1;
    }

   double dWidth = cap.get(CV_CAP_PROP_FRAME_WIDTH); //get the width of frames of the video
   double dHeight = cap.get(CV_CAP_PROP_FRAME_HEIGHT); //get the height of frames of the video

    cout << "Frame size : " << dWidth << " x " << dHeight << endl;

    namedWindow("MyVideo",CV_WINDOW_AUTOSIZE); //create a window called "MyVideo"
    namedWindow("MyNegativeVideo",CV_WINDOW_AUTOSIZE);

    while (1)
    {
        Mat frame;
        Mat contours;

        bool bSuccess = cap.read(frame); // read a new frame from video

         if (!bSuccess) //if not success, break loop
        {
             cout << "Cannot read a frame from video stream" << endl;
             break;
        }

        flip(frame, frame, 1);
        imshow("MyVideo", frame); //show the frame in "MyVideo" window

        Canny(frame, contours, 500, 1000, 5, true);
        imshow("MyNegativeVideo", contours);

        if (waitKey(30) == 27) //wait for 'esc' key press for 30ms. If 'esc' key is pressed, break loop
       {
            cout << "esc key is pressed by user" << endl;
            break;
       }
    }
    return 0;
}

/quote