[N0cky]

Part of #208: the first PR, with the fields ffmpeg writes natively. Publisher, subtitle and language follow once the ASIN post-step has landed.

What is written (under metadata_tagging_enabled, no new settings)

	M4B/M4A/MP4	MP3	FLAC
Description (Audible summary)	desc + ldes	TXXX:description	DESCRIPTION
Genre (top-level genres, ; -joined)	©gen	TCON	GENRE
Media type Audiobook	stik=2	–	–
Gapless	pgap=1	–	–

• Line breaks in the summary become single spaces (the existing sanitizer drops them; this keeps paragraphs from running together).
• Genres: new primaryGenres on AudibleAudiobook = Audnexus genres of type: 'genre' (sub-genre tags left out) or the top of each catalog ladder. The existing genres display list is unchanged. Audiobookshelf splits genre tags on ;; Audible genre names contain & and , but no ;.

Data

• When tagging is on, the organize job looks up getAudiobookDetails(asin) once and shares it with the existing missing-series backfill (src/lib/processors/organize-tag-details.ts), so there is at most one lookup per import.
• Behaviour change: with tagging on, every import with an ASIN now makes that one Audnexus request (before: only when series was missing). A failed lookup is non-fatal and falls back to the stored description.

Testing

• Tag mapping unit tests per format, plus real-ffmpeg integration tests (round trip via ffprobe)
• Checked against the image's ffmpeg 9.0.2: standard mdir atoms kept, stik/pgap read correctly by mutagen
• Full npm test suite green, tsc clean, no new ESLint findings, docker build -f dockerfile.unified OK

[kikootwo]

Thanks @N0cky, this is a nice set of tags, and keeping paragraphs apart in the description is a good catch.

I'm going to take it from here: it'll land on our branch with you as co-author, on top of the ASIN tag change that's going in first, since that reworks the same tagging code. A few changes on top:

• FLAC: the description gets written as comment. A file that already has a description would otherwise keep both, and Audiobookshelf shows them joined ("old;new").
• Descriptions get capped at 16 KB. A very long one can make ffmpeg fail to start, and then the file loses all of its tags.
• A / in a genre name gets replaced, since Audiobookshelf splits genres on / before it tries ;.
• When the series is already known, the details lookup gets a 15-second limit, so a slow Audible doesn't hold up the import.
• A test that the new tags still read back after the ASIN step rewrites the file.

I'll close this PR once that lands, so I'm leaving it open until then.

[N0cky]

Thanks, sounds good, and good catches on the FLAC duplicate and the / split. Happy to do publisher/subtitle/language on top once the ASIN step is in, or leave them to you if you'd rather fold them in while you're there. Your call.

[kikootwo]

Thanks! I'll keep the re-land to what's here so it goes in cleanly. Publisher, subtitle and language would be great as a follow-up from you. Base it on main once this lands; I'll ping you here when it does.

[kikootwo]

@N0cky this landed in #419 with you as co-author, and it'll be in the next release. Thanks again!

It's on main now, so publisher, subtitle and language can be based on it whenever you're ready. The tag text helpers now live in src/lib/utils/metadata-text.ts, and the ASIN post-step (addMp4FreeformTags() in metadata-tagger.ts) is where new freeform items go.

[kikootwo]

@N0cky this is out in v1.2.10: https://github.com/kikootwo/ReadMeABook/releases/tag/v1.2.10