Streaming non-mp3 audio to Sonos

Has anyone been able to send their Sonos a format other than MP3 via the Media Extractor? I can do this via my media library (sending MP3, M4A, OGG, etc., all work fine), but I’m not sure if HA is doing some transcoding that I am not aware of when sending that over.

For the media_extractor.play_media service, I have only been successful sending a link to an mp3, otherwise, I am getting incorrect MIME type errors.

Service call to play an m4a file:

service: media_extractor.play_media
  media_content_id: >-<... rest of url>
  media_content_type: music
  entity_id: media_player.my_sonos


soco.exceptions.SoCoUPnPException: UPnP Error 714 received: Illegal MIME-Type from <ip>

This seems odd because Sonos claims to support a range of formats.

I’m also a bit confused about the media_content_type portion of this service call, as the dropdown list gives a list of some options such as MUSIC, CHANNEL and PLAYLIST MUSIC, but for all of the predefined options, I get errors like the following:

Logger: homeassistant.components.sonos.media_player
Source: components/sonos/
integration: Sonos (documentation, issues)

Sonos does not support a media type of “MUSIC”

I have only been able to make this work with music (case matters). So I’m not sure if this isn’t working because I am providing an incorrect content type (what other options are there that Sonos accepts)?