What makes an album - rlipscombe/nemplode GitHub Wiki

Windows Media Player and Windows Media Center regularly seem to group the tracks from a single album into multiple albums. How do they figure out which tracks go together? Why is this broken? How can it be fixed?

For example, I've got "All That You Can't Leave Behind" by U2. Windows Media Player has decided to break it into two albums.

Supposedly, it's driven by the WM/WMCollectionGroupID, WM/WMCollectionID and WM/WMContentID tags. These are documented here.

Looking at my MP3 collection, I have the following Windows Media Player tags:

  • WM/Provider - the name of the provider of the attribute values. This is UTF16-encoded text. For all of the files in my collection, this is "AMG".
  • WM/WMCollectionGroupID, WM/WMCollectionID, WM/WMContentID - these are documented as how you group a collection.
  • WM/UniqueFileIdentifier - semi-colon delimited list of file identifiers. These all appear to be AMG-related in my MP3 collection.
  • WM/MediaClassPrimaryID, WM/MediaClassSecondaryID - these are GUIDs to identify the type of media (music, video, etc.; what type of music or video...). For my MP3 files, these appear to always be set to d1607dbc-e323-4be2-86a1-48a42a28441e (music) and 00000000-0000-0000-0000-000000000000 (unknown).

WM/WMCollectionGroupID, WM/WMCollectionID

Bizarrely, in my U2 example, WM/WMCollectionGroupID is identical for all of the files in the album, as is WM/WMCollectionID. In fact, these two values are identical. That is: WMCollectionGroupID == WMCollectionID.

WM/WMContentID varies for each file, as expected.

Similarly, "Homogenic" by Bjork is split into two albums. That doesn't have any WM/WMCollectionID-related tags at all.

OK, so that's not it. What next?

Fix the albums in WMP and see what changed in the files.

I combined the two "Homogenic" albums together. What changed? Nothing, according to WinMerge. Therefore, Windows Media Player appears to be keeping the two files correlated in its database.

OK. Let's go spelunking in the database. Fortunately, that's vaguely documented as well.

Apparently nothing's changed in the database. Annoying.

Hmmm. It appears that WMP uses WM/AlbumArtist to do the grouping as well, so "Various Artists" albums, and those with "feat." seem to break it.

Album Art

Windows Media Player keeps a file called AlbumArt_{guid}_Large.jpg (and _Small) in the folder next to the MP3 files. The GUID is the same as the value of WM/WMCollectionID and WM/WMCollectionGroupID. Since those are always the same in my MP3 collection, I can't tell which is used.

Also

Also: what, if anything, do these values represent? Can I just copy a value from MusicBrainz (for example).