MusicBrainz tags: MUSICBRAINZ_ALBUMID or MusicBrainz Album Id

25 Apr 2022 14:13 musicbrainz

I noticed that some of my music collection doesn’t have the correct album art. While investigating, I discovered an unrelated problem with the MusicBrainz tags.

Because I’m old-school, I rip physical CDs to .FLAC files, tag the FLAC files with MusicBrainz Picard, and then transcode those to .MP3 files using a Rakefile and ffmpeg. I generally do this on my Linux box, and then use Syncthing to ensure that the FLAC files are pushed to my Synology NAS, and the MP3 files are replicated as relevant.

Earlier today, on my Windows laptop, I noticed that some of my MP3 files were missing album artwork – and I’d forgotten that they were MP3 files – so I opened the Music folder in Picard and was puzzled that almost none of my music was correctly grouped into albums.

Using the “Lookup” function on an arbitrary file in Picard correctly identified the music track, but there was a discrepancy: The track had MUSICBRAINZ_ALBUMID tags, and Picard was suggesting the addition of MusicBrainz Album Id tags.

Some quick searching on the internet later, and I found this:, which pointed me to, which lays out the cause:

  • For MP3 files (i.e. ID3v2 tags), Picard uses TXXX: MusicBrainz Album Id tags.
  • For FLAC files (i.e. Vorbis tags), Picard uses MUSICBRAINZ_ALBUMID tags.

My transcoding script – which is here – just uses ffmpeg to transcode each FLAC file into an MP3 file. It would seem that ffmpeg just converts the Vorbis tags to TXXX ID3v2 tags. Which makes sense – why would it know that MusicBrainz uses different names?

There doesn’t seem to be a way to fine-tune the behaviour of the -map_metadata option to ffmpeg (which is apparently implied by default, since I don’t use it explicitly), so my options seem to be as follows:

  1. Accept the situation; my MP3 files won’t be properly grouped by album, etc., as far as MusicBrainz is concerned.
  2. Use something other than ffmpeg to transcode the files.
  3. Have the Rakefile make a second pass to fix up the MusicBrainz tags.

For now, I’ll just live with it.