Irene's profile - activity

Hello, I'm trying to get frames from video (avi-file). I'm under Windows,32bit, QT 5.2.0(Mingw-compiler), OpenCV 2.4.8. It's really a simple thing, i must be really dumb, but I can't get it. Here's the code:

CvCapture *capture = NULL;
capture = cvCaptureFromAVI("road4n.avi");//this file in the build folder
if(!capture){
    return -1;
}//more code here, but it doesn't work...

The program finishes with the code -1. When I remove the if condition, no errors occur, but the rest dosen't perform anyway. I've tried different paths, like "C:/road4n.avi", writing the full path to the build directory, using like all sorts of slashes etc with no result at all. I've also tried cvCaptureFromFile but it dosen't work either, but cvCaptureFromCAM(0) works fine. At some places they say that the recompilation of the opencv might solve the problem, but maybe it's easier than that? Thank you in advance!

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UPD: I've edited the code so that no old-fashioned functions are used, so now it's:

VideoCapture cap("road4n.avi");
if(!cap.isOpened()) // check if we succeeded
return -1;

Result's still the same:(

hello, i suggest you look at this topic character recognition. There seem to be a few links with tutorials and code samples.

Hello, do you mean that you need an environment to use OpenCV? It's just OpenCV is a library, which can be integrated into compiler (like QT, or Visual Studio etc). Was that your question?

Hello, hope it's not too late, i've had similar kind of problem in Windows, it seems that the path is wrong, try to copy the path from the explorer, maybe you've missed something. You could also try to look for an answer here: no rule to make target problem

Thank you, berak! I added the code (but for now I dealt with the problem by commenting the whole procedure))

Hello, I am new to OpenCV and QT, so perhaps the question is in the wrong section. I use OpenCV 2.4.8 and QT 5.2.2, I was trying to build the project i found on the web, it was made in QT 4.7 and OpenCV 2.3 and I get this nasty error.
Google says CvOpenGLCallback derives from opencv_highgui, so I added highgui.h in the header file and it didn't work. Is there a way to deal with it or i should better find older versions of programs and try using them? Thank you.

UPD: Here's the code.

CV_IMPL void cvCreateOpenGLCallback( const char* window_name, CvOpenGLCallback callbackOpenGL, void* userdata, double angle, double zmin, double zmax)
{
    if (!guiMainThread)
        CV_Error( CV_StsNullPtr, "NULL guiReceiver (please create a window)" );
    QMetaObject::invokeMethod(guiMainThread,
        "setOpenGLCallback",
        Qt::AutoConnection,
        Q_ARG(QString, QString(window_name)),
        Q_ARG(void, (void)callbackOpenGL),
        Q_ARG(void*, userdata),
        Q_ARG(double, angle),
        Q_ARG(double, zmin),
        Q_ARG(double, zmax)
        );
}

This bit is in "window_QT.cpp", so it must be used only when window opens.