Qt World Summit: Register Today!

QMediaPlayer (dsengine.dll) problem.

  • Hello everyone!

    I hope someone can help me. I've got problem with a new version of Qt (5.8) in QMediaPlayer work. I run RTSP via IP-Camera. In case when I run application through Qt Creator (debug or release - nevermind) and start my QMediaPlayer realisation, it starts OK without issues. But if I build my project, install it on other machine (dynamic link) - video not starts.

    Error log said: The QMediaPlayer object does not have a valid service or QMediaPlayer::ServiceMissingError wich means the same.

    I build on Windows platform and start application on Windows 7 and higher with LAV Filters 0.69 on it.

    Actually, before Qt 5.8, I built on 5.7 and earlier and it works fine. Problem causes dsengine.dll. If I change it to library from 5.7 version or earlier - application runs RTSP correctly.

    So, can anybody offer any solution? Just use older versions of library?

    Some code of player realisation class:

    RtspPlayer::RtspPlayer(QVideoWidget *out, const QString &host, int port, const QString &path,
                           const QString &login, const QString &password, QObject *parent) : Transport(parent)
        _player = new QMediaPlayer;
        QUrl url(QString("rtsp://%1:%2@%3:%4%5").arg(login, password, host, QString::number(port), path));
        connect(_player, SIGNAL(error(QMediaPlayer::Error)), this, SLOT(catchErr(QMediaPlayer::Error)));
        connect(_player, &QMediaPlayer::mediaStatusChanged, this, &RtspPlayer::restartVideo);
    bool RtspPlayer::start()
        emit success();
        return true;

    Thanks for advance!

  • Lifetime Qt Champion


    Did you check the bug report system ?

  • Cheked. Not found anything about 5.8. Created own bug: https://bugreports.qt.io/browse/QTBUG-59589

  • Lifetime Qt Champion

    Thanks !

  • Problem solved. It was bug in Inno setup, which corruped Qt5Multimedia.dll somehow.

Log in to reply