QML video gives Error: "No valid frames decoded before end of stream" some of the time

[mkre]

Hello, I'm trying to get a QML media player + video output working. The media is played about nine out of ten times. But sometimes the media isn't loaded at all, and I have no reason why.

Application output shows - Error: "No valid frames decoded before end of stream" - when the media isn't loaded. It seems like this might be a bug in GStreamer, but I haven't found much about how to work around it using QT.

Here's my QML file

import QtMultimedia 5.8
import QtQuick 2.12
import QtQuick.Window 2.12

Item {

    height: Screen.height
    width: Screen.width

    MediaPlayer {
        autoLoad: true
        autoPlay: false
        id: player
    }

    VideoOutput {
        anchors.fill: parent
        id: videoOutput
        source: player
    }
}

And here is the code that is loading the media / telling the media player to play (I didn't include all the code, and its hobbled together from different files):

// connections
    connect(stackedViews->getMediaPlayer(), SIGNAL(stateChanged(QMediaPlayer::State)), this, SLOT(animationStateChanged(QMediaPlayer::State)));
    connect(stackedViews->getMediaPlayer(), SIGNAL(mediaStatusChanged(QMediaPlayer::MediaStatus)), this, SLOT(mediaStatusChanged(QMediaPlayer::MediaStatus)));

// slots 
void BootDisplay::animationStateChanged(QMediaPlayer::State state)
{
    if (state == QMediaPlayer::StoppedState)
    {
        qDebug() << "Boot animation finished!";
    }
}

void BootDisplay::mediaStatusChanged(QMediaPlayer::MediaStatus status)
{
    if (status == QMediaPlayer::MediaStatus::LoadedMedia)
    {
        qDebug() << "Media loaded into player";
        stackedViews->getMediaPlayer()->play();
    }
}

// getMediaPlayer function
QMediaPlayer* StackedViews::getMediaPlayer()
{
    QMediaPlayer* obj = videoView->rootObject()->children()[0]->findChild<QMediaPlayer*>();
    if(obj) {
        return obj;
    }
    else {
        qDebug() << "Can't find the MediaPlayer!!!";
        return nullptr;
    }
}