Definition of a Work
A work in MusicBrainz is defined as:
A Work is a musical creation or a creative combination of existing musical creations. Works can be performed and recorded to create recordings. Recordings can be creatively combined to create new recordings, which are also new Works.
A creative act involving two or more Recordings creates a both a new Recording as well as a new Work.
Works for Compilations, DJ-Mixes and Mash-ups
These types of Recordings consist of two or more original Recordings. The new Recording's Artist Credit gives information about the artist(s) original recording whereas the associated Work for the new Recording gives information about created the compilation, DJ-Mix or Mash-up.
Artist Credits for Works
A work artist_credit is used to indicate the artist(s) commonly associated with a work. The actual composer of the work is defined via an artist-work AR. For classical works the artist credit should point to the composer.
Pete Marsh from the BBC recently offered up these edge cases that require more thought about this:
In most cases as Rob suggested it's going to be reasonably easy to assign an artist credit to a work. No-one's going to argue with associating Kylie with Can't Get You Out of My Head or Sinatra with My Way. Well, actually they might, but here's a few other cases where it's not by any means cut and dried. I think that who you associate with a song is down to age and geographical location. There's no right answers here. Multiple associations might be the only way forward, but I suspect there's a reason that you haven't suggested that...?
- Mr Tambourine Man - The Byrds or Bob Dylan
- Killing Me Softly - Roberta Flack or The Fugees
- Hallelujah - Leonard Cohen or Jeff Buckley or Alexandra Burke
- Twist and Shout - Isley Brothers or The Beatles
- I Get By With A Little Help From My Friends - The Beatles or Joe Cocker
- Ob-La-Di, Ob-La-Da - The Beatles or Marmalade
- Father and Son - Cat Stevens or Boyzone
- Barracuda - Heart or Fergie
- Man Who Sold The World - David Bowie or Lulu or Nirvana
- Tainted Love - Soft Cell, Gloria Jones or Marilyn Manson
- First Cut is the Deepest - Rod Stewart, PP Arnold, Cat Stevens
- Boys of Summer - Don Henley or the Ataris
- Knockin' on Heaven's Door - Bob Dylan or Guns 'n' Roses
- My Favourite Things - Julie Andrew or John Coltrane
- Woodstock - Joni Mitchell or Matthews Southern Comfort
These are all off the top of my head but I could go on, and on, and on. I'm not sure if this counts as the tip of the iceberg but it's maybe not far off. It gets even trickier when you get to 'standards'. Who would you associate with 'Summertime'? or 'I've Got You Under My Skin'?
This rule could also be stated using the concept of the first recording:
A work artist_credit is used to indicate the artist(s) who first recorded with a work. The actual composer of the work is defined via an artist-work AR. For classical works the artist credit should point to the composer.
This fails for some cases like Twist and Shout - Isley Brothers or The Beatles This song was first recorded by Top Notes then covered by the Isley Brothers. Associating this track with [Top Notes], seems a bit far fetched.
Another possible solution is to not use the Artist Credit field and rely only on ARs to indicate who has performed a work.
ISWCs for Works
In most cases, ISWCs should be attached to only one Work. Rare cases may require an ISWC to be attached to multiple works.
This page describes proposed Work Types.
Tricky things to consider
- ISWCs attached to multiple works: http://chatlogs.musicbrainz.org/musicbrainz-devel/2010/2010-09/2010-09-13.html#T19-31-11-56868
- Work artists: http://lists.musicbrainz.org/pipermail/musicbrainz-style/2010-April/009355.html
- ARs to the medium level: http://jira.musicbrainz.org/browse/MBS-802
- Fuzzy ARs: http://chatlogs.musicbrainz.org/musicbrainz-devel/2010/2010-09/2010-09-13.html#T20-18-59-315250
- Covers of covers: Next_Generation_Schema/Track_Relationships_Conversion#Cover_Relationship_Type_Discussion