QMediaFormat has multiple enum types, where several identifiers are colliding. Consider the identifier MP3 in the following:

class QMediaFormat {
    enum FileFormat {
        ...
        MP3,
    };
    enum class AudioCodec {
        ...
        MP3,
    };
};

In QML, this is exposed as "MediaFormat.MP3". This makes it ambiguous which value applies. When trying to access this value from QML, the result is an undefined value.