I am trying to access the Description field shown in Apple Music (iTunes), but it is not working as I would expect. I have found out Apple stores the field with the tag TIT3 (by peeking at the mp3 binary), but it seems not to be storing this in a way that MP3Tag, or the command-line tool eyeD3 can find it. If I set TIT3 using MP3Tag, Apple Music does not show the value in its Description field.
Not sure what's going on, but it looks like I'll have to use the Comments field for my meta-info and my comments. :-/
Apple Music version 1.2.5.7
MacOS version Monterey 12.6.1 (21G217)
MP3Tag version 1.7.4 (75)
It seems this problem specifically occurs with mp3 files. I tried with an m4a file and things worked; Apple Music uses the "desc" field and MP3Tag can work with that. Not sure what's going on with MP3 files!
Thank you! It looks like Apple is using this incorrectly in two ways, then (in mp3 files). It is using that identifier for what it calls Description, and it also isn't storing the data in a way that mp3 tag readers can find. :-/
In the old days, with iTunes, one could force the program to write the database contents to tags when modifying the tag version. But as V2.3 could be converted to V2.3 it did not do any harm to existing data but wrote all available database data to tags.
I don't know if this still works.
I installed id3v2, and it does find the TIT3 frame. So, I must be entering something wrong in MP3Tag's custom tag setup (there are like 3 possible places to do that). Or it's possible that MP3Tag is just missing this somehow. Still investigating!
Even if I get it to work, though, it looks like Apple's Description field is not a good place to store additional metadata (such as the language of the lyrics or an external database ID). I do want the info to be accessible in Apple Music for smart playlists....
Well I set up a column in the File List, setting Value to "$metasep(TIT3,\)" and Field to "TIT3", but it looks like MP3Tag is actually saving to "TXXX" with a sub-field of "TIT3". So it looks like there should be a way for me to get MP3Tag to access the right info, I just haven't figured out how to do it yet.
Okay, I think I've solved it. I just needed to use SUBTITLE, which from what I can determine is the internal name MP3Tag maps to a variety of different ID3 tags based on the particular file format.
The reference at
https://docs.mp3tag.de/mapping/
did not make it clear to me that that is what the "Internal" listing for each tag means. Now I know!
I'm also guessing that any tag name I enter that isn't documented there gets converted to TXXX, as a user-defined frame. Please let me know if my understanding is correct and complete.
You may see with the example of the subtitle field that this information is saved in various atoms, chunks, fields - so there has to be an internal representation which (and that is the clever bit) MP3tag writes to the correct formats of the target format.
So, please use only the MP3tag internal names.
As an additional remark: you can always use View → Extended Tags... to inspect all the fields that are read by Mp3tag for a specific file (it also shows SUBTITLE with the contents of what you've entered at Description in Music.app).