can't see a video play but only music in Qt

[baluk]

Hi,

I want to play a video in my application. But whenever I try to runt he application, I get the message "WARNING: Phonon::createPath: Cannot connect Phonon::MediaObject ( no objectName ) to Phonon::VideoWidget ( no objectName )." And I can hear the music but not video. Here is my code

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    Phonon::VideoPlayer *player =
             new Phonon::VideoPlayer(Phonon::VideoCategory, this);
         player->play(QUrl("path"));
         player->show();
}
 
#include <QMainWindow>
#include <phonon/VideoPlayer>
#include <phonon/backendcapabilities.h>
#include <QUrl>
#include <phonon>
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    Ui::MainWindow *ui;
};

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    Phonon::VideoPlayer *player =
             new Phonon::VideoPlayer(Phonon::VideoCategory, this);
         player->play(QUrl("path"));
         player->show();
}

#include <QMainWindow>
#include <phonon/VideoPlayer>
#include <phonon/backendcapabilities.h>
#include <QUrl>
#include <phonon>
namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
};

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I tried to run the code from http://www.qtcentre.org/threads/3048...w-black-screen but didn't work. Can any one please tell me what else should be required to play a video.

Thank You,
Baluk

[tbscope]

You have the correct decoder installed?

[baluk]

I am sorry but what decoder I should use. I thought Qt takes the default one that is provided in my windows vista, isn't it so. I don't have much idea about decoder stuff I am trying to find it anyway.

Thank You,
Baluk

[squidge]

Unless you have a codec capable of playing the video, all you'll get is audio.

We can't tell you which decoder to use as we don't know your file format.

[baluk]

I want to play avi, mp3 and mkv format file.

[squidge]

avi and mkv are only containers, what is the file type that you will be playing inside those containers? eg. xvid.

[baluk]

oke. File type is VLC media file.

[squidge]

No, it's not.

That's just the registered player you are using to play the file.

[baluk]

Oke. Now I got to understand what is file format. I want to play avc1 and MPGV codec files.

[squidge]

Install FFDShow

[baluk]

I have it installed on my system. My audio was playing with this codec support only.

[hicham]

http://bugreports.qt.nokia.com/browse/QTBUG-13062

[baluk]

http://bugreports.qt.nokia.com/browse/QTBUG-13062

So according to the link, I can't play a video using Qt 4.7. Is there any other way I could make it possible.

[baluk]

I moved to Qt 4.6.2 and tried to run my application. But I still couldn't succeed. Here I am copying my code. Could any one please check If it is running on your system.

#include <QMainWindow>
#include <phonon/VideoPlayer>
#include <phonon/VideoWidget>
#include <phonon/backendcapabilities.h>
#include <QUrl>
#include <phonon>
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
protected:
    void changeEvent(QEvent *e);
 
private:
    Ui::MainWindow *ui;
};
 
#endif // MAINWINDOW_H
 
//.CPP file
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
        qDebug() << Phonon::BackendCapabilities::availableAudioOutputDevices();
 
        Phonon::MediaObject *mediaObject = new Phonon::MediaObject(this);
 
             Phonon::VideoWidget *videoWidget = new Phonon::VideoWidget(this);
             Phonon::createPath(mediaObject, videoWidget);
 
             Phonon::AudioOutput *audioOutput =
                 new Phonon::AudioOutput(Phonon::VideoCategory, this);
             Phonon::createPath(mediaObject, audioOutput);
             mediaObject->setCurrentSource(QUrl("file.mkv or .avi"));
            connect(mediaObject, SIGNAL(finished()), mediaObject, SLOT(deleteLater()));
             mediaObject->play();
 
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}
 
//.pro file
 
#-------------------------------------------------
#
# Project created by QtCreator 2010-10-10T23:15:17
#
#-------------------------------------------------
 
QT       += opengl phonon multimedia
 
TARGET = video
TEMPLATE = app
 
 
SOURCES += main.cpp\
        mainwindow.cpp
 
HEADERS  += mainwindow.h
 
FORMS    += mainwindow.ui
 
wince*{
DEPLOYMENT_PLUGIN += phonon_ds9 phonon_waveout
}

#include <QMainWindow>
#include <phonon/VideoPlayer>
#include <phonon/VideoWidget>
#include <phonon/backendcapabilities.h>
#include <QUrl>
#include <phonon>
namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();

protected:
    void changeEvent(QEvent *e);

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

//.CPP file

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

        qDebug() << Phonon::BackendCapabilities::availableAudioOutputDevices();

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

             Phonon::VideoWidget *videoWidget = new Phonon::VideoWidget(this);
             Phonon::createPath(mediaObject, videoWidget);

             Phonon::AudioOutput *audioOutput =
                 new Phonon::AudioOutput(Phonon::VideoCategory, this);
             Phonon::createPath(mediaObject, audioOutput);
             mediaObject->setCurrentSource(QUrl("file.mkv or .avi"));
            connect(mediaObject, SIGNAL(finished()), mediaObject, SLOT(deleteLater()));
             mediaObject->play();

}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

//.pro file

#-------------------------------------------------
#
# Project created by QtCreator 2010-10-10T23:15:17
#
#-------------------------------------------------

QT       += opengl phonon multimedia

TARGET = video
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui

wince*{
DEPLOYMENT_PLUGIN += phonon_ds9 phonon_waveout
}

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Thank You,
baluk

[baluk]

Hi,

My problem is solved. Now I can play a video in my Qt app. It was solved when I enable the corresponding decoder in the ffdshow video decoder ( which is responsible for all format video play). Before I was overlooked the issue when running the application.

[somnathbanik]

Hi,

My problem is solved. Now I can play a video in my Qt app. It was solved when I enable the corresponding decoder in the ffdshow video decoder ( which is responsible for all format video play). Before I was overlooked the issue when running the application.

Hi,
I am new to Qt and facing the same issue. I am using windows XP and also install k-Lite codec, but still not working, then I uninstalled that and installed FFDSHOW, do I need to configure anywhere in my system. Please suggest me.

[baluk]

Did you open the ffdshow window and check the available video types and if they are enabled or disabled.

[xairoy]

I tried to play DIVX encoded .avi file. But it is not playing. I have also installed ffdshow and I have checked that DIVX XIDV codecs are enabled. Can somebody help me.

[Chiz]

Hi,

My problem is solved. Now I can play a video in my Qt app. It was solved when I enable the corresponding decoder in the ffdshow video decoder ( which is responsible for all format video play). Before I was overlooked the issue when running the application.

Can you write, where and what did you do to see video?

[mk_researchfellow]

can anybody tell me in ffdshow video decoder what option shud i enable for playing .avi video file.I can only hear the music but no video........