[WebUI] display multiple genres for album

[certuna]

The navidrome db stores Genre for individual tracks. Many albums have songs from different genres on them. In the Album view, the navidrome UI only displays one genre, even if the album has tracks with different genres tagged (note: not multiple genres per track, just a different genre for each track). The UI should display it as a list, for example "Pop, Disco, House, Hip-Hop".

[deluan]

We will need to introduce a genre table, with many-to-many relationships with artist, album and media_file. Then add a /genre rest endpoint to be consumed by the UI

[deluan]

While doing some work towards multi-valued tags, I just found out that the newest version of ffmpeg supports multi-valued tags (at least genre EDIT: and Vorbis comments):

From TagLib:

GENRE                      - "Experimental"
GENRE                      - "Progressive Rock"

From ffmpeg:

GENRE           : Experimental;Progressive Rock

Not great (we will have to split the string - what if ; is a valid value for the field), but it is better than nothing!

[certuna]

I think it's safe for us to assume that ; is not a valid value for the field, so many other music applications also treat ; as a separator, even if it's non-standard.

by the way, I've just tried this for id3v2.4, and ffprobe (29-May-2021 snapshot) still doesn't do multivalued (null-separated) tags for neither genre nor artist, so I guess it can parse multiple frames (how Vorbis does multi-valued tags), but not null-separated strings within one frame (how id3v2 does it).

[deluan]

I think it's safe for us to assume that ; is not a valid value for the field

I was referring to any fields, not only genre. I think ; would work for genre, grouping and maybe others, but not for artist (ex: Kairon; IRSE!)

Anyway, I decide to implement genre before grouping, and will accept ; and / as separators. Maybe will make it configurable.

[certuna]

/ as separator is problematic with a lot more artist names than ;.

Emby has the same problem, it splits by / (not just for id3v2.3 where that's the official separator but also for id3v2.4) so it needs a whitelist, and that's a rabbit hole you really don't want to go down.

[deluan]

will accept ; and / as separators

For genre and grouping only. For artist, I'm not planning on any separator. Maybe ; but that's out of the scope for now, let's focus on genre

Do you think / would be problematic for genre? Seems to be a common practice...

[certuna]

/ is fine for genre yes. Looking through all the hundreds of genres on RYM, haven't found any with that.

[deluan]

Implemented as part of #1251:

Will close this when the PR is merged

[github-actions]

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