QMediaPlayer resolution returns (-1x-1)

QMediaPlayer * Player = new QMediaPlayer(this);

Player->setMedia(QUrl::fromLocalFile(Filename));

Player->setVideoOutput(Screen);

int Width = Player->media().canonicalResource().resolution().width();

Player->play();
Screen->show();

Width is returned -1 in this case, so is the height if we try to get it, I searched the whole forums, the bug tracker and asked on the IRC channel, no one knew the answer, so I can expect its a bug, please correct me if I am mistaken.