BASS - Batch Audio Selection for Subsonic

BASS is a tool to automatically generate playlists for a Subsonic server, such as Navidrome.

It selects tracks randomly, but weighted according to their rating, play history, and so on.

You configure BASS using flags or environment vars:

Flag	Env var	Description
subsonic-server	SUBSONIC_SERVER	Base URL for the server, e.g. https://music.example.com/
subsonic-user	SUBSONIC_USER	Username for the subsonic server, may be blank if auth is not required
subsonic-pass	SUBSONIC_PASS	Password for the subsonic server, may be blank if auth is not required
run-at	RUN_AT	Time to run playlist generation. If not specified, runs immediately. Must be a full time including timezone (e.g. 03:00:00+02:00)
playlist-name	PLAYLIST_NAME	Name of the playlist to create/update (default: "Daily Mix")
target-length	TARGET_LENGTH	Total length of tracks to add to the playlist (default: 18 hours)
weight-starred	WEIGHT_STARRED	How to weight starred (loved) tracks (default: 20)
weight-rated-1	WEIGHT_RATED_1	How to weight tracks rated 1/5 (default: 0)
weight-rated-2	WEIGHT_RATED_2	How to weight tracks rated 2/5 (default: 0.5)
weight-rated-3	WEIGHT_RATED_3	How to weight tracks rated 3/5 (default: 1)
weight-rated-4	WEIGHT_RATED_4	How to weight tracks rated 4/5 (default: 5)
weight-rated-5	WEIGHT_RATED_5	How to weight tracks rated 5/5 (default: 10)
weight-never-played	WEIGHT_NEVER_PLAYED	How to weight tracks with a play count of zero (default: 5)
weight-rarely-played	WEIGHT_RARELY_PLAYED	How to weight tracks with a play count under half the average (default: 3)
weight-frequently-played	WEIGHT_FREQUENTLY_PLAYED	How to weight tracks with a play count over double the average (default: 1)
weight-same-album	WEIGHT_SAME_ALBUM	How to weight tracks from the same album as the previous song (default: 20)
weight-same-artist	WEIGHT_SAME_ARTIST	How to weight tracks from the same artist as the previous song (default: 15)
weight-same-genre	WEIGHT_SAME_GENRE	How to weight tracks from the same genre as the previous song (default: 10)
weight-early-track	WEIGHT_EARLY_TRACK	How to weight tracks at positions 1-3 on an album (default: 10)
weight-middle-track	WEIGHT_MIDDLE_TRACK	How to weight tracks at positions 4-6 on an album (default: 5)
weight-late-track	WEIGHT_LATE_TRACK	How to weight tracks at positions 7-10 on an album (default: 1)
weight-extended-track	WEIGHT_EXTENDED_TRACK	How to weight tracks at positions 11+ on an album (default: 0.75)
weight-duplicate	WEIGHT_DUPLICATE	How to weight tracks that have already been picked (default: 0)
log.level	LOG_LEVEL	Minimum level of logs which should be displayed (default: INFO; alternatives: WARN, ERROR, DEBUG)
log.format	LOG_FORMAT	Format for logs (default: text; alternatives: json)

Weighting algorithm

Each track starts with a weight of 1.0, which is then multiplied by five components:

• The score from the track rating (starred, rated 1-5)
• The score from the play count (never played, rarely played, frequently played)
• The score from matching the last song (album, artist, genre)
• The score from being a duplicate
• The score from the track position on the album (early, middle, late, extended)

The first listed weight wins within each section (e.g., if a song is both starred and rated 5, its "track rating" score will be the starred weight).

A weight of 1.0 makes no change, a weight of 0.0 excludes the track entirely, and higher weights make it more likely to be picked.