Is there a way to index or access arbitrary Ogg/Vorbis tags via mpd?

[sjlongland]

Hi all,

I have a large collection of music in Ogg/Vorbis format, curated using custom tools that I have written myself to do tagging and file placement.

In particular, while I try to keep to using "standard" tags, I have some additional non-standard tags that I use… notably:

• VARIANT refers to a particular recording of a given artist's song
• FLAGS is a comma-separated list of "flags" that indicate common properties of different songs (e.g. live, remastered, single, extended… etc)

stuartl@vk4msl-ws:~/music/by-track-artist/Queen$ vorbiscomment ../../.by-uuid/4691/896e/bd9d/4a81/8c39/5f01/a2df/50ca.ogg | grep '^\(TITLE\|VARIANT\|FLAGS\)='
TITLE=You’re My Best Friend
VARIANT=Backing Track Mix
stuartl@vk4msl-ws:~/music/by-track-artist/Queen$ vorbiscomment ../../.by-uuid/85ec/0666/6c00/11ea/bfde/acb7/f707/1baa.ogg | grep '^\(TITLE\|VARIANT\|FLAGS\)='
TITLE=You're My Best Friend
stuartl@vk4msl-ws:~/music/by-track-artist/Queen$ vorbiscomment ../../.by-uuid/8690/39cb/e7ea/4860/9593/b504/0811/6ac0.ogg | grep '^\(TITLE\|VARIANT\|FLAGS\)='
FLAGS=Remastered 2011
TITLE=You're My Best Friend

(The files are stored under a path derived by UUID to make syncing via rsync efficient: the file name never changes even if tags do. UUID is another non-standard tag in the file.)

I'm conscious that MPD seems to have a fixed list of tags it supports: https://mpd.readthedocs.io/en/stable/protocol.html#tags

I was wondering if it were possible to expose those other tags like VARIANT? I recognise that from MPDs perspective, these would just be seen as plain "strings" and it'll be up to other tools I write to bust those apart and process them separately. I don't need them indexed or searchable at this point, I'd just like to be able to "see" them.

The other alternative of course is I just ignore MPD's library support, and instead create my own that can be used to inject URIs into MPD… which may be the best route forward. Any solution proposed to #1236 may work too for this use case, although my application is somewhat different.

[MaxKellermann]

The readcomments command can be used to download arbitrary Vorbis comments of a song, but you can't search the database by those.