Thankfully, Picard already offers the internal "tags" _releasecomment and _releasegroupcomment which can easily be used in scripting to separate albums for file/path naming purposes.

For instance, let’s take the Peter Gabriel albums all named "Peter Gabriel" but nicely separatable using the _releasegroupcomment "Car", "Scratch", "Melt" and "Security".

I’m a strong believer in the approach that all info needed should be regeneratable from the file’s tags, so I used to store these as tags releasecomment and releasegroupcomment, but recently found out that beets uses a similar approach by inventing an inofficial "Picard-like" tag MusicBrainz Album Comment.

Before all this drifts apart too much, I suggest officially introducing two new tags that could be picked up and used by other software like beets, Mp3tag and foobar2000, to name only a few, and be officially supported by Picard. Picard already has _releasecomment and _releasegroupcomment internally, so this shouldn’t be too much change.

See discussion on the beets forum, proposal on Hydrogenaudio and Mp3tag.

I should like to suggest these, because the former is already used in beets:

'MusicBrainz Album Comment' (for ID3v2)
'----:com.apple.iTunes:MusicBrainz Album Comment' (for MP4)
'MUSICBRAINZ_ALBUMCOMMENT' (for Vorbis Comments)
'MusicBrainz/Album Comment' (for ASF/WMA)

'MusicBrainz Release Group Comment' (for ID3v2)
'----:com.apple.iTunes:MusicBrainz Release Group Comment' (for MP4)
'MUSICBRAINZ_RELEASEGROUPCOMMENT' (for Vorbis Comments)
'MusicBrainz/Release Group Comment' (for ASF/WMA)

Picard users could then use something like
%album%$if(%releasegroupcomment%, (%releasegroupcomment%))
in their file naming and have the tag stored, so the same could be used in other software like beets, Mp3tag, foobar2000.

What do you think?

@outsidecontext: Interested?