Can flexible attributes be written to files as tags?

[seadowg]

I sometimes need to write a flexible attribute to an album for things like version:

beet modify -w album:'The Downward Spiral' albumversion='Definitive Edition'

As far as I've seen, that attribute isn't then written to actual files, so I've often just used Picard to edit tags like this (that aren't in the beets field set), but that's definitely less ideal for a remote server where I'd rather be using a CLI over SSH. Is there really no way to write arbitrary tags with beets? I'm struggling to find anything in the documentation for it.

[seadowg]

It seems like this can potentially be achieved by writing a plugin looking at this older forum post and some documentation around an updated possible approach.

Is there no existing plugin that already handles writing arbitrary tags or a command that will do it? I've not managed to find either. If that's actually the case, I can look at writing a plugin that allows configurable custom tags with something like:

custom_tags:
    - version:
        mp3: Version
        default: VERSION

That would add support for the version attribute to be saved to mp3 files as Version and VERSION for FLAC etc.

[seadowg]

Just in case this doesn't get answered, it does look like you can use albumdisambig to save album versions to files. From looking at an old forum post and doing some playing around, it looks like this gets stored as musicbrainz album comment and musicbrainz_albumcomment for MP3 and FLAC respectively. This works well with Navidrome (they're default aliases for albumversion so you don't even need to customize tag mappings), but won't work with Roon as it only respects version.