Qt application failed to load plugin



  • I have Qt application which work with camera and multimedia features. When I copy this application on another PC, which haven't installed Qt SDK,
    @QCamera::availableDevices()@
    return empty string(thi pc have camera and camera work in another applications like skype ).

    I add in to the environment QT_DEBUG_PLUGINS and have such debug log

    bq. Debug: QFactoryLoader::QFactoryLoader() looking at "plugins/mediaservice/dsengined.dll" (plugin\qfactoryloader.cpp:158, void __thiscall QFactoryLoader::update(void))
    Debug: Got keys from plugin meta data ("directshow") (plugin\qfactoryloader.cpp:183, void __thiscall QFactoryLoader::update(void))
    Debug: QFactoryLoader::QFactoryLoader() looking at "plugins/mediaservice/qtmedia_audioengined.dll" (plugin\qfactoryloader.cpp:158, void __thiscall QFactoryLoader::update(void))
    Debug: Got keys from plugin meta data ("audiocapture") (plugin\qfactoryloader.cpp:183, void __thiscall QFactoryLoader::update(void))
    Debug: QFactoryLoader::QFactoryLoader() looking at "plugins/mediaservice/wmfengined.dll" (plugin\qfactoryloader.cpp:158, void __thiscall QFactoryLoader::update(void))
    Debug: Got keys from plugin meta data ("windowsmediafoundation") (plugin\qfactoryloader.cpp:183, void __thiscall QFactoryLoader::update(void))
    Debug: QFactoryLoader::QFactoryLoader() looking at "D:/new folder/mediaservice/dsengined.dll" (plugin\qfactoryloader.cpp:158, void __thiscall QFactoryLoader::update(void))
    Debug: Got keys from plugin meta data ("directshow") (plugin\qfactoryloader.cpp:183, void __thiscall QFactoryLoader::update(void))
    Debug: QFactoryLoader::QFactoryLoader() looking at "D:/new folder/mediaservice/qtmedia_audioengined.dll" (plugin\qfactoryloader.cpp:158, void __thiscall QFactoryLoader::update(void))
    Debug: Got keys from plugin meta data ("audiocapture") (plugin\qfactoryloader.cpp:183, void __thiscall QFactoryLoader::update(void))
    Debug: QFactoryLoader::QFactoryLoader() looking at "D:/new folder/mediaservice/wmfengined.dll" (plugin\qfactoryloader.cpp:158, void __thiscall QFactoryLoader::update(void))
    Debug: Got keys from plugin meta data ("windowsmediafoundation") (plugin\qfactoryloader.cpp:183, void __thiscall QFactoryLoader::update(void))
    Debug: QMediaPluginLoader: loading metadata for iid "org.qt-project.qt.mediaserviceproviderfactory/5.0" at location "/mediaservice" (qmediapluginloader.cpp:110, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: QMediaPluginLoader: Inserted index 0 into metadata: QJsonObject({"Keys": ["directshow"],"Services": ["org.qt-project.qt.camera"],"index": 0}) (qmediapluginloader.cpp:127, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: QMediaPluginLoader: Inserting new list for key: "org.qt-project.qt.camera" (qmediapluginloader.cpp:142, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: QMediaPluginLoader: Inserted index 1 into metadata: QJsonObject({"Keys": ["audiocapture"],"Services": ["org.qt-project.qt.audiosource"],"index": 1}) (qmediapluginloader.cpp:127, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: QMediaPluginLoader: Inserting new list for key: "org.qt-project.qt.audiosource" (qmediapluginloader.cpp:142, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: QMediaPluginLoader: Inserted index 2 into metadata: QJsonObject({"Keys": ["windowsmediafoundation"],"Services": ["org.qt-project.qt.mediaplayer","org.qt-project.qt.audiodecode"],"index": 2}) (qmediapluginloader.cpp:127, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: QMediaPluginLoader: Inserting new list for key: "org.qt-project.qt.mediaplayer" (qmediapluginloader.cpp:142, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: QMediaPluginLoader: Inserting new list for key: "org.qt-project.qt.audiodecode" (qmediapluginloader.cpp:142, void __thiscall QMediaPluginLoader::loadMetadata(void))
    Debug: loaded library "D:/new folder/plugins/mediaservice/dsengined.dll" (plugin\qlibrary.cpp:489, bool __thiscall QLibraryPrivate::load(void))
    Warning: QLibraryPrivate::loadPlugin failed on "D:/new folder/plugins/mediaservice/dsengined.dll" : "Cannot load library D:/new folder/plugins/mediaservice/dsengined.dll: ?? ?????? ????????? ??????." (plugin\qlibrary.cpp:540, bool __thiscall QLibraryPrivate::loadPlugin(void))

    the most important string in this log - about failing load dsengined.dll is write with some encoding problem(I have a windows on russian language).
    How I can set language of this debug messages on English or how I can set correct codepage for viewing this debug message?



  • I fix this problem - add Qt5OpenDld.dll into the application directory.
    QtMultimediaWidgetsd.dll depend from Qt5OpenGld.dll


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