Write custom tags to files on import

[AlexChalk]

Hi,

My mp3 player cares about the 'AlbumSort' tag, and I'd like to add it automatically when importing files into my beets library.

I'm imagining a config that looks a lot like paths::

custom_tags:
  AlbumSort: $year $album # Sorts albums by year, then alphabetically

Does this look like a viable feature, and if not can you point me in the right direction for authoring a plugin that would add an AlbumSort tag in this way? Thanks!

[AlexChalk]

According to https://beets.readthedocs.io/en/stable/dev/plugins.html it looks like something like this should do it:

from beets.plugins import BeetsPlugin
from beets import config
import mediafile


# pip install ./beets-albumsort
class AlbumSortPlugin(BeetsPlugin):
    def __init__(self, *args, **kwargs):
        super(AlbumSortPlugin, self).__init__(*args, **kwargs)
        field = mediafile.MediaField(
            mediafile.MP3DescStorageStyle(u'AlbumSort'),
            mediafile.StorageStyle(u'AlbumSort')
        )
        self.add_media_field('AlbumSort', field)

        self.register_listener('write', self.write)

    def write(self, item, path, tags):
        tags["AlbumSort"] = f"{tags['original_year']} {tags['album']}"

But the code above does not write the tag :/.

[sampsyo]

You're on the right track here! I'm not 100% sure what's going on, but after adding a MediaField with the add_media_field method, you should be able to populate this field. Can you try removing the write listener and manually setting the field with, for example, beet modify and beet write? Looking into that will debug the first part of your solution.

Then, once the new tag is working, you can worry about how to automatically set it. I'd recommend trying database_change, which lets you modify a field every time something gets added to, removed from, or modified in the database itself—which should then get propagated to files on write.

[AlexChalk]

Hi @sampsyo, thanks for this. modify + write doesn't populate the field, exit code is 0 but tags aren't updated. So I guess I'm declaring the MediaField incorrectly.

Maybe my MP3DescStorageStyle and StorageStyle are incorrect, the example in the docs sets them both to the tag name, but this does seem a bit weird. Do you have any idea how those args are used? Thanks!

[sampsyo]

For more examples, you can see the MediaFile source code:
https://github.com/beetbox/mediafile/blob/4f70ee8a29456ca98c071e59f08310b2b9948afb/mediafile.py#L1994-L1999

[AlexChalk]

That's great, it looks like the names are important! This seems to do the trick:

from beets.plugins import BeetsPlugin
from beets import config
import mediafile


# pip install ./beets-albumsort
class AlbumSortPlugin(BeetsPlugin):
    def __init__(self, *args, **kwargs):
        album_sort_field = mediafile.MediaField(
            mediafile.MP3StorageStyle(u"TSOA"),
            mediafile.MP4StorageStyle(u"----:com.apple.iTunes:Album Sort"),
            mediafile.StorageStyle(u"Album Sort")
        )
        self.add_media_field("album_sort", album_sort_field)

        self.register_listener("write", self.write)

        super().__init__(*args, **kwargs)

    def write(self, item, path, tags):
        tags["album_sort"] = f"{tags['original_year']} {tags['album']}"