I have an application (XBMC) that reads MUSICBRAINZ_ARTISTID and MUSICBRAINZ_ALBUMID in APE and FLAC tags. In MP3Tag I have instead MUSICBRAINZ ARTIST ID and MUSICBRAINZ ALBUM ID tags (I think these are default in MP3Tag?)
So what I want to do is create the new tags and copy the contents of the existing corresponding tags. I can do this manually by selecting all files from an album and adding the new tag and then use the tag panel to update the new tag on all selected files, but I am looking for a way to automate this for my whole folder structure.
Please note that the user-friendly name in a program does not reflect the internal labelling of a field.
And no, the fields MUSICBRAINZ_ARTISTID and MUSICBRAINZ_ALBUMID are not default in MP3tag but must be user-defined fields that apparently muscibrainz adds to a file.
To copy one field to another create an action of the type "Format value" for the target field (here, I guess, "MUSICBRAINZ_ALBUMID" and enter as format string %MUSICBRAINZ ALBUM ID%.
I still doubt that 2 different fields are necessary
When I look into a mp3 file, which has been tagged with Musicbrainz Picard into ID3v2.4 tag, for example, there is stored a TXXX tag-field named "MusicBrainz Artist Id".
Mp3tag displays the tag-field name as "MUSICBRAINZ ARTIST ID".
Because I don't know the XMBC application I suppose, that XMBC displays the tag-field name as "MUSICBRAINZ_ARTISTID", as you said.
Like user 'ohrenkino' said here in this thread, I also have doubts, that you need two tag-fields with the identical content, but adressable by two names.
Because you want to copy one tag-field's content from one tag-type into another tag-type, like APE and FLAC, (what tag-type within what file-type?), it may somehow be different with the tag-field names.
Be aware that you have to fiddle around with the Mp3tag Tag Options in order to write to the correct tag-type.
Thanks for the responses. I have the "MusicBrainz WS + ID" installed which IIRC is a script that shows up under "tag sources". I guess that is what determines the actual tag that gets written.
The XBMC app parses tag data in media files and stores the results in a SQLite database. Since it's open source, it is straight forward to read through the tag parser. For whatever reason, for ID3v2 tags it looks for things like TXXX=MusicBrainz Artist Id, but when it comes to APE and Vorbis (FLAC) it only accepts MUSICBRAINZ_ARTISTID, even though it seems like Ascii space 0x20 is perfectly legal in those tags. That format is what MusicBrainz Picard tagger references in their Wiki so I suppose that's where the XBMC devs got it.
I don't know that I need both formats, but seems easy enough to keep both formats for the affected tags. I will get on with creating the action group and do some testing.
The action group works great and I was able to patch dano's MusicBrainz tag source script so it now stores the MBID data in the fields I need for XBMC.