mp3tag is changing some tags that shouldn't be touched.
When I edit the "Title" on a track in a 2-disc compilation for example, the disc number will change from "1" to "1/2".
At the same time, the "Album Artist" changes from "Nokturnal" to "Nokturnal\\Nokturnal"
How to Reproduce: Here is the example mp3.
It is tagged the way I want.
Open the file in mp3tag, edit the "Title" field to something different. The changes I mentioned above will happen. You can confirm by looking at the tags before and after in another program like foobar2000.
I am not sure whether this is really a bug.
Apparently, foobar shows the fields discnumber and totaldiscs separately, just like iTunes displays number of tracks and the total number of tracks separately - although they are stored in one tag but separated by a slash.
The double-backslash you found in ARTIST indicates that you have created a multi-value field for ARTIST each with the artist name (which makes it hard to distinguish) - you could check this in the extended tags (Alt-T) if you see two tag fields with the same name.
So as a summary: I would not see this as a bug but as different ways of displaying the same data.
Where is my interpretation wrong?
You bring up good information and I understand, but foobar2000 should display the data the same way before and after using mp3tag and it does not. To me, this indicates that mp3tag is changing those tags.
Looking at the tags more exactly, here are the precise changes made:
It changes the "Album Artist" field to "AlbumArtist".
There already is "AlbumArtist" with "Nokturnal" in it, resulting in "Nokturnal\\Nokturnal" being displayed.
It changes "DISCNUMBER" when APEv2 tags are added on top of ID3v2 ones.
Foobar reads it as "DISCNUMBER=1/2" and "TOTALDISCS=2"
It should read "DISCNUMBER=1" and "TOTALDISCS=2" as it did before.
This may be foobar2000's problem.
I don't think either of these should be automatically changed. I can use a script if I want this.
I guess this has something to do with tag type versions. Mp3tag writes all tags to the version you have selected at Tools > Options > Tags > Mpeg
I have experienced a similar behaviour with YEAR and DATE.
When both tag fields are present, foobar reads only YEAR in the foobar field "Date" before I change the files. after saving in Mp3tag, foobar shows both fields seperated by a comma. This is a new behaviour of foobar which came with one of the latest updates.
I also find this rather anoying, but I haven't found a way to disable this.
$meta(date,0) could do part of the job in foobar. This displays only the first tag field if foobar reads the field as mulitvalue tag.
But there a cases at my collection where DATE is read as the first tag field. (files changed by another software called Traktor, which always writes the YEAR field into YYYY-01-01). There this workaroud doesn't help, so I'm still looking for another solution.
$meta(album artist,0) should helb in your case.
For discnumber, use %discnumber%[/%totaldiscs%] in foobar to have both values displayed as one field.
before the band to album artist update foobar only displayed Mp3tag's ALBUMARTIST in foobar's "Band" field. Now both, Mp3tag's ALBUMARTIST and ALBUM ARTIST are displayed in foobar's "album artist".
I solved this with deleting all ALBUM ARTIST fields in Mp3tag as this was dublicate inforamtion anyway. But as I sayed above, $meta(album artist,0) should also do the job.
Thanks for the help guys!
I set both Foobar2000 and mp3tag to write only ID3v2.3 when dealing with mp3s, no APEv2, and no ID3v1. This solved the discnumber problem. I will solve the "album artist" problem with a script now that I know the correct standard is "albumartist".
However, now my dates get "removed" by mp3tag. Foobar2000 seems to use "YEAR" even if it's YYYY-MM-DD and mp3tag changes this to "DATE", which foobar2000 can't read at all.
To clarify, pone, I was using %discnumber%[/%totaldiscs%] and it was turning from 1/2 to 1/2/2.
I can't use $meta(album artist,0) because I have many albums with two albumartists.
I appreciate all the help though!