Video is a solved problem. Sonarr and Radarr find things, Plex plays them, and most weeks I do not think about it. Music and audiobooks are the other half of the stack, and they are messier in a way that turns out to be more interesting to write about: the automation is thinner, the metadata is worse, and the files arrive named like a ransom note.

Here is how that half is put together.

Music: Lidarr, slskd and Soularr

Lidarr handles the library and knows what is missing. What it is not especially good at is finding things, at least not the older, more obscure and more Australian end of what I listen to. Usenet and torrent indexers tend to carry the big releases and not much else.

Soulseek covers that gap better than anything else I have tried, because it is people sharing their actual collections rather than an index of scene releases. The problem is that Soulseek is a chat-era desktop client, not something you point a *arr at.

Three containers solve that:

  • slskd is a headless Soulseek daemon with a web UI and, crucially, an API.
  • Soularr is the glue. It polls Lidarr for missing albums, searches slskd for them, downloads what matches, and hands the result back to Lidarr to import.
  • Lidarr itself, on the nightly tag, because the music side of the *arr family moves slower and the stable builds lag further behind than they do for TV and film.

Soularr runs on a five minute loop:

environment:
  SCRIPT_INTERVAL: "300"

The settings that actually mattered

Most of Soularr’s config is fine at defaults. Three lines were not.

The first is format. I originally allowed MP3 as a fallback and regretted it, because “available” and “worth keeping” are different questions and MP3 kept winning on availability:

# FLAC preferred, AAC (.m4a/.aac) as fallback. No MP3.
allowed_filetypes = flac 24/192,flac 16/44.1,flac,m4a,aac

Dropping MP3 entirely means some albums simply do not get grabbed. That is the correct outcome. They sit in Lidarr as missing until someone shares a better copy, which on Soulseek happens more often than you would expect.

The second is match strictness. Soulseek filenames are whatever the sharer felt like that day, so a loose match will cheerfully import a live bootleg as the studio album:

minimum_filename_match_ratio = 0.8
failed_import_denylist = True

The denylist is the important half. Without it, a release that fails to import gets found again on the next pass, fails again, and loops forever.

The third is the download path, and it is the whole point of the post about the single mount:

# Same folder as before, but reached via Lidarr's /data mount so it sits on the
# SAME filesystem as the root folder (/data/Music) -> instant hardlink import.
download_dir = /data/downloads/complete/slskd

Same folder on disk, expressed through Lidarr’s /data mount rather than a separate one, which turns the import from a copy into a hardlink.

The ALAC era, and why it ended

Digging through the Lidarr config folder to write this, I found the previous version of my answer to the format question, and it was the exact opposite one. extended.conf still says:

audioFormat="alac"    # Set this to ALAC (Apple Lossless Audio Codec)
requireQuality="true"  # Enforces ALAC and lossless format during conversion

alongside three shell scripts whose entire job was to walk the library, convert every FLAC to ALAC with ffmpeg, and delete the original.

The reasoning was sound at the time. This is an all-Apple house, and for years iOS simply would not play FLAC. ALAC is also lossless, so converting between the two costs nothing in quality, and it meant everything played everywhere without thinking about it.

What changed is that the problem went away. Modern iOS handles FLAC, and Plex and Audiobookshelf both transcode on the fly anyway. Rewriting the entire library to solve a compatibility problem that no longer exists is pure churn, so now Soularr fetches FLAC and it stays FLAC.

The scripts are worth keeping around as a warning, though. Here is the business end of the newer one:

find . -type d -name "@eaDir" -prune -o -type f -iname "*.flac" -print0 | \
  xargs -0 -P 4 -I {} bash -c '
    ...
    if ffmpeg -nostdin -y -i "$file" -vn -acodec alac "$output"; then
      rm "$file"
    ...

Four parallel ffmpeg jobs, each deleting the source the moment the encode returns zero, across the whole music library, with no dry run and no way to undo it. Compare that to the audiobook script further down this post, which defaults to printing what it would do and moves duplicates aside rather than deleting them. Same author, same NAS, about eighteen months apart. The difference is entirely that in between I had a script do something I did not expect on a folder I cared about.

Those files are still sitting in the config folder. That is fine while they are only ever run by hand, but “a destructive script with no dry run, left lying about” is exactly the sort of thing that is fine right up until it is not.

Sharing back

One thing worth saying plainly, because it is easy to set up slskd as a pure leech and never think about it. Soulseek is a community of people sharing personal collections, and the whole thing falls over if everyone takes and nobody gives. My music library goes back in, read-only:

volumes:
  - /volume1/Music:/music:ro

shares:
  directories:
    - /music

The :ro is deliberate. slskd has no reason to write to the library, so it cannot.

Audiobooks and ebooks

Different problem entirely. There is no Sonarr for audiobooks, so this side is less “automation” and more “a good pipeline with a human at the front”.

Audiobookshelf is the server. It handles audiobooks, ebooks and podcasts, remembers where everyone is up to, and has decent iOS apps, which matters in this house. One small deployment note: it defaults to port 80, which is a bad neighbour on a Synology, so it gets moved:

environment:
  PORT: 10000   # override the default port 80
volumes:
  - /volume1/AudioBooks:/audiobooks
  - /volume1/Books:/Books
  - /volume1/Podcasts:/podcasts

Calibre-Web-Automated handles ebooks. The useful part over plain Calibre-Web is the ingest folder: drop a file into a watched directory and it converts, tags, covers and files it into the library without opening the Calibre desktop app.

- /volume1/downloads/book-ingest:/cwa-book-ingest   # clean drop zone CWA watches
- /volume1/Books:/calibre-library                   # final ebook library

Shelfmark sits in front of both as the request tool: search, pick, download. The interesting bit is that it routes by type. Ebooks go to the CWA ingest folder so Calibre-Web-Automated processes them. Audiobooks go straight into the Audiobookshelf library, because there is nothing to convert:

- INGEST_DIR=/cwa-book-ingest
- DESTINATION_AUDIOBOOK=/audiobooks
- HARDLINK_TORRENTS_AUDIOBOOK=false

That last line is a deliberate exception to everything I argued above. Audiobook torrents routinely arrive as multi-part RAR sets rather than playable files, so there is nothing sensible to hardlink. Copy and extract is the correct behaviour here, even though it costs the disk space.

The part no tool fixes

Audiobooks arrive named appallingly. Some are a bare author folder. Some are Richard_Powers_-_The_Overstory__Unabr_-_64k__2018____01_23__-__The_Overstory.nfo. Some are a single folder containing four unrelated Roald Dahl books. No scanner recovers from that, so I wrote two scripts.

inventory-audiobooks.sh is read-only and changes nothing. It walks the library and writes one text file listing every folder, every audio file, and the embedded tags from the first file in each folder via ffprobe. That inventory is what you actually plan from.

tidy-audiobooks.sh does the work, and its most important line is at the top:

# SAFE BY DEFAULT: DRY=1 only prints what it would do.
DRY=1

Every operation goes through one wrapper so the dry run is not something I have to remember to implement per command:

act(){ echo "+ $*"; [ "$DRY" -eq 0 ] && "$@"; }

The target layout is Author - Title, or Author - Series ## - Title for anything in a series, zero-padded so it sorts properly. Duplicates and GraphicAudio versions get moved to a _duplicates folder rather than deleted, because a script that has never made a mistake has simply not run often enough yet.

The script is also, deliberately, a hand-written list of decisions rather than clever pattern matching:

act mv "$LIB/Hanya Yanagihara"          "$LIB/Hanya Yanagihara - A Little Life"
act mv "$LIB/Douglas Stuart"            "$LIB/Douglas Stuart - John of John"

That looks like a lot of typing, and it is. But it means the script doubles as a record of every judgement call I made about the library, which a regex never would.

What it adds up to

Plex also mounts /volume1/AudioBooks, so anything in there turns up on the Apple TVs and HomePods alongside everything else. Audiobookshelf handles the phones. Both read the same tidied folders, which is the entire reason the tidying was worth doing.