How to Sync Playlist to SD Card & Modify Tag During Move

[NoahTheDuke]

Sorry for the combo title, I want to make sure others can find it.

I use beets to organize all my music. I made an .m3u playlist with ~800 songs, and I want to sync them to an sd card. I use beets move -e playlist:music_for_player -d /Volumes/mp3_player and they're copied over, which is great. However, my mp3 player does not use $albumartist, it uses $artist for sorting and separation and display, meaning that my Charlie XCX album is listed under multiple artists, one for each Charlie XCX feat. SOME_ARTIST.

I'd like to be able to perform the move and also apply a change/normalization to the moved files, replacing $artist with $albumartist. Is this possible?

[aribradshaw]

move -e is already the right command for keeping the SD-card copy outside the beets database. It exports by copying the file with store=False. The missing piece is that the copy operation emits an item_copied plugin event with the destination path.

A small local plugin can rewrite only the copied file:

import os

from beets.plugins import BeetsPlugin
from beets.util import bytestring_path, normpath


class PlayerExportPlugin(BeetsPlugin):
    def __init__(self):
        super().__init__()
        self.config.add({"root": "/Volumes/mp3_player"})
        self.register_listener("item_copied", self.item_copied)

    def item_copied(self, item, source, destination):
        root = normpath(bytestring_path(self.config["root"].as_filename()))
        destination = normpath(destination)

        try:
            if os.path.commonpath([root, destination]) != root:
                return
        except ValueError:
            return

        item.write(
            path=destination,
            tags={"artist": item.albumartist or item.artist},
        )

Configure the mount point if needed:

plugins: playerexport
playerexport:
  root: /Volumes/mp3_player

Then your existing command can stay the same:

beet move -e playlist:music_for_player -d /Volumes/mp3_player

Item.write(path=..., tags=...) writes the normal beets metadata plus the artist override to the exported file. It does not change the source file or the canonical database item. The root check also prevents unrelated beets copy operations from receiving the player-specific tag.

The relevant implementation paths are move -e, which performs an untracked copy, and item_copied, which provides the destination before the temporary path change.

[NoahTheDuke]

I'll give this a try! thank you so much.