Qt6 topics merged with General

DBus connection to omxplayer won't work

  • Hy, I try to write a wrapper to navigate the omxplayer on raspberry pi 2. The script dbuscontroll.sh works but the Qt source code do not work.

    I am not sure if the application is connected? This is the code:

        QDBusConnection *_dbus;
        _dbus = new QDBusConnection(QDBusConnection::sessionBus());
        _dbus->connectToBus(address, "org.mpris.MediaPlayer2.omxplayer");
        if( !_dbus->isConnected() ) {
            qDebug() << "not connected";
        QString dest = "org.mpris.MediaPlayer2.omxplayer";
        QString path = "/org/mpris/MediaPlayer2/";
        QString interface = "org.mpris.MediaPlayer2.Player";
        QString name = "Action";
        QDBusMessage msg = QDBusMessage::createMethodCall(dest, path, interface, name);
        msg.setArguments(QList<QVariant>() << 16);
        if( !_dbus->send(msg) ) {
            qWarning() << "error: " << _dbus->lastError().message();

    And I got this output on the console:

    Unable to query physical screen size, defaulting to 100 dpi.
    To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).
    QDBusConnectionPrivate(0x72208478) : connected successfully
    not connected
    error:  "Not connected to D-Bus server"
    QDBusConnectionPrivate(0x72208478) got message (signal): QDBusMessage(type=Signal, service="org.freedesktop.DBus", path="/org/freedesktop/DBus", interface="org.freedesktop.DBus", member="NameAcquired", signature="s", contents=(":1.29") )

    I am connected with ssh and use the dbus-monitor. It display the following output:

    signal sender=org.freedesktop.DBus -> dest=(null destination) serial=8 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
       string ":1.33"
       string ""
       string ":1.33"
    method call sender=:1.33 -> dest=org.freedesktop.DBus serial=1 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=Hello

    Can anyone tell me what's going wrong and why the message is not queued?

  • I think that I found the solution. I will test something and post the result later.

  • The solution is to set some environment variables. I set the address in qt but the environments are required for the libdbus library.

    Set the




  • Hello,

    I am performing a similar operation. How are you actually passing the address ?

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