[SOLVED] Multiple Genres Bug?

[Atair]

@Atair

Late-breaking news.

I should have been more skeptical. It turns out that even mid3v2 (which is based on mutagen) lies about the actual content of the ID3 text frames (the official name of those T... fields).

Recall in my previous post I showed the mid3v2 output for your MP3 file was

Code:

TCON=Rock-Italienisch / Italien / Rock

Quite literally this is not so!

Dumping the strings from the MP3 file, I discovered that it actually contains three TCON frames. Schematically they are

Code:

TCON Rock-Italienisch
<APIC cover art>
TCON Italien
TCON Rock

Here I've not shown the messy binary information which is intermingled with each in a file. 

APIC is the frame type for a picture and is followed by many binary bytes of the JPEG image before the occurrence of the second TCON frame.

So, mid3v2, mediainfo, and MPD's plugins are apparently aggregating the information contained in these three TCON frames, albeit in different ways.

This multiplicity of frames is explicitly in violation of the ID3v2.3 spec, which says in part

The text information frames are the most important frames, containing information like artist, album and more. There may only be one text information frame of its kind in an tag.

Remember that in ID3, as in many metadata schemes, the word "tag" refers to the entire block of metadata associated with a file while in ID3 the word "frame" refers to a single piece of metadata---what we users and the MPD developers loosely call a "tag".

The plot thickens, as the saying goes. My "legal" MP3 files will always be interpreted as having a single genre even if I use creative concatenations with various separators, while your "illegal" MP3 files will be interpreted in various ways by various softwares. 

Regards,
Kent

This is interesting and shows that a couple of tag editors and music databases seem to be programmed "defensively" so they can handle non-standard fram usage.