DISCNUMBER tag ignored in VorbisComment

[ghost]

Expected behavior

For albums with multiple discs, tracks should first be sorted by disc number.

Actual behavior

For ID3 (.mp3) it works, but not for VorbisComment (.flac, .ogg).

Steps to reproduce the behavior

1. Tag an audio file with DISCNUMBER greater than 1.
2. Scan for new audio files.
3. Take a look into graphical album view or selected playlist. All discs have number 1 and sorted wrong.

Possible solution (optional)

Detect the DISCNUMBER tag correctly in fLaC and OggS.

Server configuration

Audio Player version: (see /settings/apps)
2.0.0

[Rello]

corrected