Skip to main content
`Ctrl`+`K`

# LastGenre Plugin

The `lastgenre` plugin fetches tags from Last.fm and assigns them as genres to your albums and items.

## Installation

To use the `lastgenre` plugin, first enable it in your configuration (see Using Plugins). Then, install `beets` with `lastgenre` extra

    pip install "beets[lastgenre]"

## Usage

The plugin chooses genres based on a whitelist, meaning that only certain tags can be considered genres. This way, tags like “my favorite music” or “seen live” won’t be considered genres. The plugin ships with a fairly extensive internal whitelist, but you can set your own in the config file using the `whitelist` configuration value or forgo a whitelist altogether by setting the option to `no`.

The genre list file should contain one genre per line. Blank lines are ignored. For the curious, the default genre list is generated by a script that scrapes Wikipedia.

### Canonicalization

The plugin can also canonicalize genres, meaning that more obscure genres can be turned into coarser-grained ones that are present in the whitelist. This works using a tree of nested genre names, represented using YAML, where the leaves of the tree represent the most specific genres.

The most common way to use this would be with a custom whitelist containing only a desired subset of genres. Consider for a example this minimal whitelist:

    rock
    heavy metal
    pop

together with the default genre tree. Then an item that has its genre specified as viking metal would actually be tagged as heavy metal because neither viking metal nor its parent black metal are in the whitelist. It always tries to use the most specific genre that’s available in the whitelist.

The relevant subtree path in the default tree looks like this:

    - rock:
        - heavy metal:
            - black metal:
                - viking metal

Considering that, it’s not very useful to use the default whitelist (which contains about any genre contained in the tree) with canonicalization because nothing would ever be matched to a more generic node since all the specific subgenres are in the whitelist to begin with.

If you use canonicalization without a whitelist, the plugin will simply map every genre to its top-most root category in the tree (e.g., `Viking Metal` → `Rock`). This is a great way to keep your library broad without needing to maintain a manual list of allowed genres.

### Genre Source

When looking up genres for albums or individual tracks, you can choose whether to use Last.fm tags on the album, the artist, or the track. For example, you might want all the albums for a certain artist to carry the same genre. The default is “album”. When set to “track”, the plugin will fetch both album-level and track-level genres for your music when importing albums.

### Multiple Genres

By default, the plugin chooses the most popular tag on Last.fm as a genre. If you prefer to use a list of popular genre tags, you can increase the number of the `count` config option.

Lists of up to count genres will be stored in the `genres` field as a list and written to your media files as separate genre tags.

Last.fm provides a popularity factor, a.k.a. weight, for each tag ranging from 100 for the most popular tag down to 0 for the least popular. The plugin uses this weight to discard unpopular tags. The default is to ignore tags with a weight less then 10. You can change this by setting the `min_weight` config option.

### Specific vs. Popular Genres

By default, the plugin sorts genres by popularity. However, you can use the `prefer_specific` option to override this behavior and instead sort genres by specificity, as determined by your whitelist and canonicalization tree.

For instance, say you have both `folk` and `americana` in your whitelist and canonicalization tree and `americana` is a leaf within `folk`. If Last.fm returns both of those tags, lastgenre is going to use the most popular, which is often the most generic (in this case `folk`). By setting `prefer_specific` to true, lastgenre would use `americana` instead.

### Handling pre-populated tags

The `force`, `keep_existing` and `whitelist` options control how pre-existing genres are handled.

As you would assume, setting `force: no` won’t touch pre-existing genre tags and will only fetch new genres for empty tags. When `force` is `yes` the setting of the `whitelist` option (as documented in Usage) applies to any existing or newly fetched genres.

The following configurations are possible:

Setup 1 (default)

Add new last.fm genres when empty. Any present tags stay untouched.

    force: no
    keep_existing: no

Setup 2

Overwrite all. Only fresh last.fm genres remain.

    force: yes
    keep_existing: no

Setup 3

Combine genres in present tags with new ones (be aware of that with an enabled `whitelist` setting, of course some genres might get cleaned up - existing genres take precedence over new ones though. To make sure any existing genres remain, set `whitelist: no`).

    force: yes
    keep_existing: yes

Attention

If `force` is disabled the `keep_existing` option is simply ignored (since `force: no` means `not touching` existing tags anyway).

## Genre Ignorelist

Last.fm tags are crowd-sourced, so they can be wrong — especially for artists whose names are shared with or confused with others. For example, a “Drum And Bass” artist named “Fracture” might incorrectly receive “Metal” tags. The ignorelist lets you reject specific genres globally or per-artist.

Another example for the ignorelist is to exclude genres that are technically correct but not useful to you. For example, you might want to exclude “Ska” for “Bob Marley”, even though it is a valid genre for his music.

Filtering is done in two places: when fetching genres from Last.fm and when resolving to a final genre list (during canonicalization and whitelisting).

This means that existing genres are also filtered when `force` and `keep_existing` options are enabled (or `cleanup_existing` is enabled with `force` disabled).

To enable this feature, add an `ignorelist` section to your `lastgenre` configuration:

    lastgenre:
        ignorelist:
            fracture:
                - ^(heavy|black|power|death)?\s?(metal|rock)$|\w+-metal\d*$
                - progressive metal
            bob marley:
                - ska
            '*':
                - electronic

A combination of regex patterns and plain genre names is possible. The `'*'` key applies globally to all artists — use it to block genres you never want, regardless of artist. Patterns are matched against the full genre string, so a plain `metal` will not match `heavy metal` unless you write a regex like `.*metal`.

Attention

- The global key `'*'` must be surrounded by single quotes so that YAML does not interpret it as an anchor.

- Any regex pattern that starts with a special YAML character (`[`, `*`, or `:`) or ends with `:` must be surrounded by quotes.

- Prefer single quotes (`'...'`) when quoting is necessary, as they treat backslashes literally (no double-escaping required).

- Because the ignorelist uses plain YAML, you do not need to double-escape backslashes in unquoted or single-quoted strings (e.g., use `\w`, not `\\w`).

## Genre Normalization (Aliases)

Last.fm tags often contain variant spellings, abbreviations, or inconsistent formatting (e.g., “hip-hop”, “hiphop”, and “hip hop”). The normalization feature uses an ordered list of regular expression aliases to map these variants to a single canonical name before any other filtering or canonicalization takes place.

This feature is enabled by default and uses a built-in alias table that covers many common cases, such as mapping “dnb” to “drum and bass” or “r&b” to “rhythm and blues”. Set `aliases: no` to turn it off entirely.

You can replace these aliases with your own by setting `aliases` to an inline mapping in your configuration. The keys are the canonical genre names (which support `\1` / `\g<N>` back-references to regex capture groups) and the values are lists of regex patterns.

Note

The same formatting and quoting rules regarding YAML special characters and backslashes mentioned in the Attention box in the Genre Ignorelist section apply here as well.

The full default mappings are shown below - copy and paste this into your config below the `lastgenre.aliases` section to customize it:

    # Ampersands / Delimiters
    drum and bass:
        - d(rum)?[ &n/]*b(ass)?
    r&b:
        - r(hythm)?[ &n/]*b(lues)?
    rock and roll:
        - rock[- ‐'&n/]*roll

    # Hyphenation
    \1-\2:
        - ([ckj])[- ]*(pop)
        - (j)[- ]*(rock)
        - (post)[- ]*(\w+)
        - (g?lo)[- ]*(fi)
        - ([pg])[- ]*(funk)
        - (synth)[- ]*(pop)
    avant-garde:
        - avant[- ]*(garde?)?

    # Adding space
    \1 \2:
        - (nu)[ -]*(disco|jazz|metal|soul)
        - (dark)[ -]*(wave)
        - (blues|folk|indie|gothic|progressive|alternative|punk)[ -]*(rock)
        - (ska)[ -]*(jazz)
        - (synth)[- ]*(funk)
        - (glitch|hip|trip)y?(?:[ -]*hip)?[ -]*(hop)

    # Removing delimiters
    \1\2:
        - (synth)[- ]*(wave)
        - (psy)[ -]*(trance)
        - (chill)[ -]*(out)

    # Old School spellings: old-school death metal, oldschool hip-hop, old-skool-jungle/-hardcore
    old school death metal:
        - old[ -]*(?:school|skool)[ -]+death[ -]*metal
    old school hip hop:
        - old[ -]*(?:school|skool)[ -]+hip[ -]*hop
    old school \1:
        - old[ -]*(?:school|skool)[ -]+(\w+)

    # Terminology / Synonyms
    electronic:
        - electronic music
    world music:
        - world
    downtempo:
        - down[ -]*beat
    shoegaze:
        - shoegaz(e?r?|ing)
    footwork:
        - (chicago )?footwork( music)?
    juke:
        - (chicago )?juke( music| house)?

    # Compound genres
    alternative rock:
        - alt[ -]*rock
    # negative lookahead avoids matching 'gothic metal'
    gothic rock:
        - goth(?!ic)([ -]*rock)?
    # avoids matching 'progressive metal'
    progressive rock:
        - prog([ -]*rock)?
    punk rock:
        - punk
    # psy folk, psych-pop, psychedelic-rock, psychedelic soul, but not psychedelic (standalone)
    psychedelic \1:
        - psy(?:ch(?:edelic)?)?[ -]*(folk|pop|rock|soul)
    dixieland:
        - dixieland[ -]*jazz

## Choosing the Right Tool

With multiple ways to filter and map genres, here is a quick guide on when to use what:

- Aliases: Use these first to fix spelling variants and abbreviations (e.g., `dnb` → `drum and bass`).

- Ignorelist: Use this for error correction when Last.fm results are not accurate, or for precise per-artist or global exclusions (e.g., rejecting `Metal` for specific electronic artists).

- Canonicalization: Use this to automatically map specific sub-genres to broader categories (e.g., `Grindcore` → `Metal`).

- Whitelist: Use this to finally limit your library to a predefined set of genres. When combined with canonicalization, the plugin will try to map a sub-genre to its closest whitelisted parent. Anything else is dropped.

## Configuration

To configure the plugin, make a `lastgenre:` section in your configuration file. Default configuration:

    lastgenre:
        auto: yes
        canonical: no
        cleanup_existing: no
        count: 1
        fallback: null
        force: no
        keep_existing: no
        min_weight: 10
        prefer_specific: no
        source: album
        whitelist: yes
        title_case: yes
        ignorelist: no
        aliases: yes

The available options are:

- auto: Fetch genres automatically during import. Default: `yes`.

- canonical: Use a canonicalization tree. Setting this to `yes` will use a built-in tree. You can also set it to a path, like the `whitelist` config value, to use your own tree. Default: `no` (disabled).

- cleanup_existing: This option only takes effect with `force: no`, Setting this to `yes` will result in cleanup of existing genres. That includes canonicalization and whitelisting, if enabled. If no matching genre can be determined, the `fallback` is used instead. Default: `no` (disabled).

- count: Number of genres to fetch. Default: 1

- fallback: A string to use as a fallback genre when no genre is found `or` the original genre is not desired to be kept (`keep_existing: no`). You can use the empty string `''` to reset the genre. Default: None.

- force: By default, lastgenre will fetch new genres for empty tags only, enable this option to always try to fetch new last.fm genres. Enable the `keep_existing` option to combine existing and new genres. (see Handling pre-populated tags). Default: `no`.

- keep_existing: This option alters the `force` behavior. If both `force` and `keep_existing` are enabled, existing genres are combined with new ones. Depending on the `whitelist` setting, existing and new genres are filtered accordingly. To ensure only fresh last.fm genres, disable this option. (see Handling pre-populated tags) Default: `no`.

- min_weight: Minimum popularity factor below which genres are discarded. Default: 10.

- prefer_specific: Sort genres by the most to least specific, rather than most to least popular. Note that this option requires a `canonical` tree, and if not configured it will automatically enable and use the built-in tree. Default: `no`.

- source: Which entity to look up in Last.fm. Can be either `artist`, `album` or `track`. Default: `album`.

- whitelist: The filename of a custom genre list, `yes` to use the internal whitelist, or `no` to consider all genres valid. Default: `yes`.

- title_case: Convert the new tags to TitleCase before saving. Default: `yes`.

- ignorelist: A mapping of artist names (or the global `'*'` key) to lists of genres to exclude. See Genre Ignorelist for more details. Default: `no`.

- aliases: Controls genre alias normalization. Set to `yes` (default) to use the built-in alias table, `no` to disable normalization entirely, or an inline mapping of canonical genre names to lists of regex patterns to replace the built-in table with your own. See Genre Normalization (Aliases) for details.

## Running Manually

In addition to running automatically on import, the plugin can also be run manually from the command line. Use the command `beet lastgenre [QUERY]` to fetch genres for albums or items matching a certain query.

By default, `beet lastgenre` matches albums. To match individual tracks or singletons, use the `-A` switch: `beet lastgenre -A [QUERY]`.

To preview the changes that would be made without applying them, use the `-p` or `--pretend` flag. This shows which genres would be set but does not write or store any changes.

To disable automatic genre fetching on import, set the `auto` config option to false.

## Tuning Logs

To enable tuning logs, run `beet -vvv lastgenre ...` or `beet -vvv import ...`. This enables additional messages at the `DEBUG` log level, showing for example what data was received from last.fm at each stage of genre fetching (artist, album, and track levels) before any canonicalization or whitelist filtering is applied. Tuning logs are useful for adjusting the plugin’s settings and understanding its behavior, though they can be quite verbose.