Explanation:

The tag with the key "track" can be in the form of "current/total".

(Like described in avformat.h of the libav library)

QMediaMetaData returns for these valid tags the value 0.

Solution 1:

Make QMediaMetaData:TrackNumber a QString instead of an int.

Solution 2:

Do something like:

QString::fromUtf8(tag->value).split('/').at(0).toInt()

Maybe somewhere near QFFmpegMetaData::addEntry...