QMediaPlayer fails to open audio stream

Opening a video stream works fine with QMediaPlayer, however the following fails when it's an audio stream:

QMediaPlayer *player = new QMediaPlayer(this);
QUrl url("/path/to/file.mp3");
QFile *file = new QFile(url);
file->open(QFile::ReadOnly);
player->setMedia(url, file);
player->play();

When it's a mp3 the console output is:
GStreamer: Could not determine the type of the stream
If it's an ogg:
Error: "Could not demultiplex stream."

I find it odd because if I do the same with AVI or MP4, video files in general it works, I took a look at Qt sources but I clueless.

And it works if I don't pass the file pointer, as it isn't
loaded as a stream, but of course that isn't an option for me
as I have a custom QIODevice to read encrypted files and I
also plan to have another custom to play from dlna streams.

Thanks.