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Plugin cannot be loaded for module “QtMultimedia”. Cannot load library declarative_multimedia.dll



  • I'm creating a PyQt5 + qml application. Windows 10, PyQt5 5.13.2, Python 3.6. Everything works fine until I try and import QtMultimedia, which results in the error message:

    QQmlApplicationEngine failed to load component
    file:///C:/Users/user/PycharmProjects/Project/project/pyqt-gui/pyqt-gui/main.qml:9
    plugin cannot be loaded for module "QtMultimedia": Cannot load library C:\Users\user\PycharmProjects\Project\venv\lib\site-packages\PyQt5\Qt\qml\QtMultimedia\declarative_multimedia.dll: The specified module could not be found.
    

    This seems to persist across different virtual environments and versions of PyQt and QtMultimedia. I've also confirmed that the .dll file is present in the environment.

    main.qml:

    import QtQuick 2.12
    import QtQuick.Window 2.12
    import QtQuick.Layouts 1.3
    import QtQuick.Controls 2.13
    import QtQuick.Shapes 1.11
    import QtQuick.Dialogs 1.1
    import QtQuick.Controls.Styles 1.4
    import QtCharts 2.3
    import QtMultimedia 5.10
    
    ApplicationWindow {
        id: appWindow
        visible: true
        width: 1920
        height: 1080
        color: "#313131"
        title: qsTr("Project PyQt")
    }
    

    main.py:

    import sys
    
    from PyQt5.QtQml import QQmlApplicationEngine
    from PyQt5.QtWidgets import QApplication
    from PyQt5.QtCore import QUrl
    
    from interface import Interface
    
    if __name__ == '__main__':
        app = QApplication(sys.argv)
    
        appEngine = QQmlApplicationEngine()
    
        context = appEngine.rootContext()
    
        appEngine.load(QUrl('pyqt-gui/main.qml'))
    
        win = appEngine.rootObjects()[0]
    
        # Register Python classes with qml
        interface = Interface(app, context, win)
    
        context.setContextProperty('iface', interface)
    
        win.show()
        try:
            apcode = app.exec_()
        except:
            print('there was an issue')
        finally:
            sys.exit(apcode)
    

    Installation of pyqt is from a fresh venv or conda env + pip install pyqt5

    On adding os.environ["QT_DEBUG_PLUGINS"] = "1" the console output is:

    QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms" ...
    QFactoryLoader::QFactoryLoader() looking at "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qminimal.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qminimal.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
        "MetaData": {
            "Keys": [
                "minimal"
            ]
        },
        "archreq": 0,
        "className": "QMinimalIntegrationPlugin",
        "debug": false,
        "version": 331008
    }
    
    
    Got keys from plugin meta data ("minimal")
    QFactoryLoader::QFactoryLoader() looking at "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qoffscreen.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qoffscreen.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
        "MetaData": {
            "Keys": [
                "offscreen"
            ]
        },
        "archreq": 0,
        "className": "QOffscreenIntegrationPlugin",
        "debug": false,
        "version": 331008
    }
    
    
    Got keys from plugin meta data ("offscreen")
    QFactoryLoader::QFactoryLoader() looking at "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qwebgl.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qwebgl.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
        "MetaData": {
            "Keys": [
                "webgl"
            ]
        },
        "archreq": 0,
        "className": "QWebGLIntegrationPlugin",
        "debug": false,
        "version": 331008
    }
    
    
    Got keys from plugin meta data ("webgl")
    QFactoryLoader::QFactoryLoader() looking at "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qwindows.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qwindows.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
        "MetaData": {
            "Keys": [
                "windows"
            ]
        },
        "archreq": 0,
        "className": "QWindowsIntegrationPlugin",
        "debug": false,
        "version": 331008
    }
    
    
    Got keys from plugin meta data ("windows")
    QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/shires/PycharmProjects/DeepLabCut/venv/Scripts/platforms" ...
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qwindows.dll"
    QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platformthemes" ...
    QFactoryLoader::QFactoryLoader() looking at "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platformthemes/qxdgdesktopportal.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platformthemes/qxdgdesktopportal.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QPA.QPlatformThemeFactoryInterface.5.1",
        "MetaData": {
            "Keys": [
                "xdgdesktopportal",
                "flatpak",
                "snap"
            ]
        },
        "archreq": 0,
        "className": "QXdgDesktopPortalThemePlugin",
        "debug": false,
        "version": 331008
    }
    
    
    Got keys from plugin meta data ("xdgdesktopportal", "flatpak", "snap")
    QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/shires/PycharmProjects/DeepLabCut/venv/Scripts/platformthemes" ...
    QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/styles" ...
    QFactoryLoader::QFactoryLoader() looking at "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/styles/qwindowsvistastyle.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/styles/qwindowsvistastyle.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QStyleFactoryInterface",
        "MetaData": {
            "Keys": [
                "windowsvista"
            ]
        },
        "archreq": 0,
        "className": "QWindowsVistaStylePlugin",
        "debug": false,
        "version": 331008
    }
    
    
    Got keys from plugin meta data ("windowsvista")
    QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/shires/PycharmProjects/DeepLabCut/venv/Scripts/styles" ...
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/styles/qwindowsvistastyle.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick.2/qtquick2plugin.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QtQuick2Plugin",
        "debug": false,
        "uri": [
            "QtQuick.2"
        ],
        "version": 331008
    }
    
    
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick.2/qtquick2plugin.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Window.2/windowplugin.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QtQuick2WindowPlugin",
        "debug": false,
        "uri": [
            "QtQuick.Window.2"
        ],
        "version": 331008
    }
    
    
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Window.2/windowplugin.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Layouts/qquicklayoutsplugin.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QtQuickLayoutsPlugin",
        "debug": false,
        "uri": [
            "QtQuick.Layouts"
        ],
        "version": 331008
    }
    
    
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Layouts/qquicklayoutsplugin.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Controls.2/qtquickcontrols2plugin.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QtQuickControls2Plugin",
        "debug": false,
        "uri": [
            "QtQuick.Controls.2"
        ],
        "version": 331008
    }
    
    
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Controls.2/qtquickcontrols2plugin.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Shapes/qmlshapesplugin.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QmlShapesPlugin",
        "debug": false,
        "uri": [
            "QtQuick.Shapes"
        ],
        "version": 331008
    }
    
    
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Shapes/qmlshapesplugin.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Dialogs/dialogplugin.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QtQuick2DialogsPlugin",
        "debug": false,
        "uri": [
            "QtQuick.Dialogs"
        ],
        "version": 331008
    }
    
    
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Dialogs/dialogplugin.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtCharts/qtchartsqml2.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QtChartsQml2Plugin",
        "debug": false,
        "uri": [
            "QtCharts"
        ],
        "version": 331008
    }
    
    
    loaded library "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtCharts/qtchartsqml2.dll"
    Found metadata in lib C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtMultimedia/declarative_multimedia.dll, metadata=
    {
        "IID": "org.qt-project.Qt.QQmlExtensionInterface/1.0",
        "archreq": 0,
        "className": "QMultimediaDeclarativeModule",
        "debug": false,
        "uri": [
            "QtMultimedia"
        ],
        "version": 331008
    }
    
    
    Cannot load library C:\Users\shires\PycharmProjects\DeepLabCut\venv\lib\site-packages\PyQt5\Qt\qml\QtMultimedia\declarative_multimedia.dll: The specified module could not be found.
    QLibraryPrivate::loadPlugin failed on "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtMultimedia/declarative_multimedia.dll" : "Cannot load library C:\\Users\\shires\\PycharmProjects\\DeepLabCut\\venv\\lib\\site-packages\\PyQt5\\Qt\\qml\\QtMultimedia\\declarative_multimedia.dll: The specified module could not be found."
    QQmlApplicationEngine failed to load component
    file:///C:/Users/shires/PycharmProjects/DeepLabCut/deeplabcut/pyqt-gui/pyqt-gui/main.qml:9 plugin cannot be loaded for module "QtMultimedia": Cannot load library C:\Users\shires\PycharmProjects\DeepLabCut\venv\lib\site-packages\PyQt5\Qt\qml\QtMultimedia\declarative_multimedia.dll: The specified module could not be found.
    
    Traceback (most recent call last):
      File "C:/Users/shires/PycharmProjects/DeepLabCut/deeplabcut/pyqt-gui/main.py", line 20, in <module>
        win = appEngine.rootObjects()[0]
    IndexError: list index out of range
    QLibraryPrivate::unload succeeded on "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/styles/qwindowsvistastyle.dll" 
    QLibraryPrivate::unload succeeded on "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/plugins/platforms/qwindows.dll" 
    On QtCore unload, "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtCharts/qtchartsqml2.dll" was leaked, with 2 users
    On QtCore unload, "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick.2/qtquick2plugin.dll" was leaked, with 2 users
    On QtCore unload, "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Controls.2/qtquickcontrols2plugin.dll" was leaked, with 2 users
    On QtCore unload, "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Dialogs/dialogplugin.dll" was leaked, with 2 users
    On QtCore unload, "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Layouts/qquicklayoutsplugin.dll" was leaked, with 2 users
    On QtCore unload, "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Shapes/qmlshapesplugin.dll" was leaked, with 2 users
    On QtCore unload, "C:/Users/shires/PycharmProjects/DeepLabCut/venv/lib/site-packages/PyQt5/Qt/qml/QtQuick/Window.2/windowplugin.dll" was leaked, with 2 users
    
    Process finished with exit code 1
    


  • Same issue here, also using PyQt5 + QML but in macOS, with Python 3.6 and QtMultimedia 5.11. Did you manage to fix it?
    I'm running the program in the terminal python3 mygui.py in case it matters.


  • Lifetime Qt Champion

    Hi,

    From the looks of it, the deployment of PyQt5 is wrong in that respect. You should check with their author.

    You might also want to try PySide2.


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