Problem with Phonon::VideoWidget in QDialog

Question

I am writing an application using a QDialog as the main Window. In this application I have 3 QGroupBox, one with several Buttons, the second one with a GLWidget displaying webcam content (captured and processed using OpenCV and displayed with OpenGL), and in the third one I was trying to play different videos using Phonon (basically I intend to select the videos using a QComboBox, although this is not relevant to my problem).

Everything works, the GUI initializes, does everything that I need... until I try to create a VideoWidget object. This is the code of my class:

    GUIT::GUIT(QWidget *parent, Qt::WFlags flags)
    {       

        // Initialization of the different QGroupBox
        createVideo();  
        createButtons();
        createScoreFE();
        createPhonon();

        gbScoreFE->hide();

        QHBoxLayout *layout = new QHBoxLayout;
        QVBoxLayout *mainLayout = new QVBoxLayout;
        mainLayout->addWidget(gbVideo, 0, 0);
        mainLayout->addWidget(gbButtons, 1, 0);
        mainLayout->addWidget(gbScoreFE, 0, 0);

        layout->addLayout(mainLayout);
        layout->addWidget(gbPhonon);

        gbPhonon->hide();   

        this->setLayout(layout);

        layout->setSizeConstraint(QLayout::SetFixedSize);

    }

And the method that crashes is:

void GUIT::createPhonon()
{

    gbPhonon = new QGroupBox(tr("Test"));

    // This line makes the program to stop executing.
    Phonon::VideoWidget *_player_video = new Phonon::VideoWidget;

    QVBoxLayout *layout = new QVBoxLayout;

    gbPhonon->setLayout(layout);

}

How does it crashes?? Well, it just kills several threads after creating a new VideoWidget. It just looks like:

The thread 'Win32 Thread' (0x12e8) has exited with code 1 (0x1).
The thread 'Win32 Thread' (0x1304) has exited with code 1 (0x1).
The thread 'Win32 Thread' (0xf20) has exited with code 1 (0x1).
The thread 'Win32 Thread' (0xdec) has exited with code 1 (0x1).
The thread 'QThread' (0x1e20) has exited with code 1 (0x1).
The thread 'Win32 Thread' (0x19b0) has exited with code 1 (0x1).
The thread 'Win32 Thread' (0x1f58) has exited with code 1 (0x1).
The thread 'Win32 Thread' (0x1794) has exited with code 1 (0x1).

The truth is that I'm a little bit confused about this problem. It arise while I was writing a QWidget where I was going to create the VideoWidget with its components... I checked other Phonon classes, and the GUI is not affected when they are initialized. Eg:

Phonon::MediaObject *mediaObject = new Phonon::MediaObject(this);

I have also tried to reproduce the problem with a simpler GUI, and it compiles and works with no problem, so there should be something that is in conflict with Phonon. I thought it could be the GLWidget, but I disconnected this part of the GUI... and it still kills the threads.

Has somebody run into a similar problem? Has somebody any insight of what could be going wrong or how to check the thread kills?

Answer 1

I think QDialog is the reason to cause that problem.

Answer 2

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QVBoxLayout>
#include <QGroupBox>
#include <Phonon>
#include <QPushButton>

class Dialog : public QDialog
{
    Q_OBJECT
public:
    explicit Dialog(QWidget *parent = 0);

private:
    QGroupBox *gbButtons;
    QGroupBox *gbPhonon;
    QVBoxLayout *mainLayout;
    QPushButton *btnPlay;

    Phonon::AudioOutput *audioOut;
    Phonon::VideoWidget *vWidget;
    Phonon::MediaObject *mObject;

    void createPhonon();
    void createButtons();

private slots:
    void playVideo();
};

#endif // DIALOG_H


#include "dialog.h"

Dialog::Dialog(QWidget *parent) :
    QDialog(parent)
{
    mainLayout = new QVBoxLayout();
    createButtons();
    createPhonon();

    setLayout(mainLayout);
}

void Dialog::createButtons()
{
    gbButtons = new QGroupBox("Buttons");
    btnPlay = new QPushButton("Play",gbButtons);
    connect(btnPlay,SIGNAL(clicked()),this,SLOT(playVideo()));
    mainLayout->addWidget(gbButtons);
}

void Dialog::createPhonon()
{
    gbPhonon = new QGroupBox("Phonon");

    QVBoxLayout *vLayout = new QVBoxLayout();
    vWidget = new Phonon::VideoWidget;
    mObject = new Phonon::MediaObject;
    audioOut = new Phonon::AudioOutput(Phonon::VideoCategory);

    Phonon::createPath(mObject,vWidget);
    Phonon::createPath(mObject,audioOut);

    vLayout->addWidget(vWidget);
    gbPhonon->setLayout(vLayout);
    mainLayout->addWidget(gbPhonon);

    gbPhonon->hide();
}

void Dialog::playVideo(){

    gbPhonon->show();
    mObject->setCurrentSource(Phonon::MediaSource("C:/Videos/Loving You Tonight.mp4"));
    mObject->play();
}