QMediaRecorder does not work with gst pipelines

Player::Player() :
    QMediaPlayer()
{
    const QMediaContent media({"rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov"});
    setMedia(media);
    play();

    connect(this, &QMediaPlayer::stateChanged, this, [](auto state){
        qDebug() << "state" << state;
    });

    QMediaRecorder mediaRecorder(this);

    connect(&mediaRecorder, &QMediaRecorder::stateChanged, this, [](auto state){
        qDebug() << "state media" << state;
    });

    connect(&mediaRecorder, &QMediaRecorder::statusChanged, this, [](auto status){
        qDebug() << "status media" << status;
    });

    QVideoEncoderSettings videoSettings;
    videoSettings.setCodec("video/mp4");
    videoSettings.setResolution(640, 480);
    mediaRecorder.setVideoSettings(videoSettings);
    mediaRecorder.setOutputLocation(QUrl::fromLocalFile("/tmp/video.mp4"));
    mediaRecorder.record();

    QTimer::singleShot(2000, [&mediaRecorder]{
        QList<QPair<QString, QVariant>> list = {
            {"location", mediaRecorder.actualLocation()},
            {"status", mediaRecorder.status()},
            {"availability", mediaRecorder.availability()},
            {"availableMetaData", mediaRecorder.availableMetaData()},
            {"containerFormat", mediaRecorder.containerFormat()},
            {"duration", mediaRecorder.duration()},
            {"error", mediaRecorder.error()},
            {"errorString", mediaRecorder.errorString()},
            {"isAvailable", mediaRecorder.isAvailable()},
            {"isMetaDataAvailable", mediaRecorder.isMetaDataAvailable()},
            {"isMuted", mediaRecorder.isMuted()},
            {"state", mediaRecorder.state()},
            //{"videoSettings", mediaRecorder.videoSettings()},
        };
        for(const auto item : list) {
            qDebug() << item.first << item.second;
        }
        mediaRecorder.stop();
    });
}