Make a custom field use length formatting

[emiham]

For the built-in length field you can use human readable notation, like 4:20 instead of 260. Is it possible to extend this behavior to custom fields? I have an album length field that I would like to behave the exact same way.

[krotname]

Yes, but not through the stock types plugin config.

The built-in length field gets that behavior because it is declared as types.DurationType() in beets/library/fields.py. DurationType is the piece that formats seconds as M:SS and parses M:SS back to seconds.

The types plugin currently only accepts:

int
float
bool
date

so this will not work:

types:
  album_length: duration

For the same behavior on an album flex field, use a small plugin that declares the field type:

from beets.dbcore import types
from beets.plugins import BeetsPlugin

class AlbumLengthTypePlugin(BeetsPlugin):
    album_types = {
        "album_length": types.DurationType(),
    }

Then enable that plugin and store the value as seconds. After that, $album_length should format like $length, and queries/parsing should go through the duration type instead of a plain string/float.

If you only need this for display and do not care about query parsing, an inline/template field is also possible, but for "behave exactly like length", the field type is the right place.

[emiham]

That works great, thank you!

[emiham]

For anyone who stumbles upon this, I made a plugin to add a length field to albums.

https://github.com/emiham/beets-albumlength