With the advent of AdvancedRelationships, it becomes possible to record in a detailed way who performed what instrument in what band, who wrote what tune, and who produced/mixed/engineered which tracks. A problem with this is that information can be recorded at several different levels: the person, the band membership, the album, and the song. This page attempts to explain how this can be confusing or contradictory, and come up with some guidelines to make sense of it all.

Relations at multiple levels

At the moment, there are two relationships that allow you to capture what role the artist played, using PerformanceRelationshipClass. They relate from artist to album and artist to track. So you can say:

• James Hetfield sang on the album "Ride the Lightning"

• James Hetfield played guitar on the track "Call of Ktulu"

Since "Call of Ktulu" is on the album "Ride the Lightning", you're then left wondering exactly what James Hetfield did. Did he sing as well, or just play guitar? In actual fact, James Hetfield usually sings and plays guitar, but on that one track he only played guitar.

There have also been suggestions that MusicalAssociationRelationshipClass should be modified so that we can also say:

• James Hetfield sings and plays guitar in the band "Metallica"

rather than just:

• James Hetfield is a member of the band "Metallica"

So there will be another level to the confusion. Finally, it's also been suggested that we should be able to add to artist records information about what the artist generally does:

• James Hetfield is a singer and guitarist

Thus there would be a four levels at which artist role can be recorded:

1. Artist (person) record

2. Relation between artist (person) and artist (group)

3. Relation between artist (person) and album

4. Relation between artist (person) and song

The big place where this is going to cause problems is when MusicBrainz data is "collapsed down" to the track level: especially when tagging music files. People are going to want each instrumentalist credited on each track, and that's going to mean retrieving information from all four levels. Any contradictions will need to be reconciled before the track can be properly tagged.

Proposed Interpretation Rule

For any particular artist, for any particular song, all the information about that artist's role on that song must reside at the same level. That level will be the lowest one at which there is some information. Any information at a higher level should be ignored.

So in James Hetfield's case, you would record:

• James Hetfield sings in Metallica (level 2)

• James Hetfield plays guitar in Metallica (level 2)

• James Hetfield plays guitar on "Call of Ktulu" (level 4)

The fact that there is special information about his role on "Call of Ktulu" means that the higher level information should be ignored. Thus, he only played guitar on that track, he didn't sing. This looks kinda weird, because in order to record information about singing (he didn't sing on that one track), you're forced to add information about playing guitar. I don't think this can be avoided though

A more complicated example:

• Ringo Starr is a drummer

• Ringo Starr is a singer

• Ringo Starr was the drummer in The Beatles

• Ringo Starr performed backing vocals in The Beatles

• Ringo Starr was the drummer on "Sgt. Pepper's Lonely Hearts Club Band"

• Ringo Starr performed lead vocals on "With a Little Help from My Friends"

• Ringo Starr was the drummer on "With a Little Help from My Friends"

Which means that he gets drumming and lead vocal credit on "With a Little Help from My Friends", just drumming credit on other songs from "Sgt. Pepper's Lonely Hearts Club Band", drumming and backing vocal credit on all other songs by The Beatles, and drumming and singing credit on solo albums and anything else he did. Phew!

The problem with this is that there is no way to record that someone who usually contributes to the band did nothing on a particular track:

• Bruce Dickinson sings in Iron Maiden

• Bruce Dickinson did nothing at all on the track "Losfer Words (Big 'Orra)"

One possibility to fix this is to introduce a special "Did nothing at all" instrument that an artist can get credit for. Which is certainly going to raise lots of questions from newbies Another possibility is to just ignore this problem and rely on people's common sense to figure out that a track which doesn't have any singing probably wasn't sung by Bruce Dickinson. I'm sure there are going to be lots of edge cases though that people will complain about.

Proposed Style Guidelines

ProposedStyleGuidelines

Note: this proposal dates from earlier than 2005-07-23 11:27:33. See below for discussion.

• All information should be recorded at the highest possible level. If an artist was only ever a member of one band, then we would rather record the fact that they were a drummer at the artist level (level 1) than at the band relationship level (level 2). This means that when someone discovers that they went on to play in some obscure other band, by default they'll get the right instrument credit. On the other hand, it means that people who add memberships of such bands will have to be careful that they don't inherit the wrong credit.

• Information shouldn't be duplicated. Don't record both that an artist is usually a drummer, and that they were a drummer and nothing else in a particular band, because this is duplicate information and can cause confusion. When someone wants to change the artist's main instrument from "guitar" to "electric guitar", they'll be left scratching their heads when this isn't reflected in their MP3 collection. Of course, if they're usually a drummer but both a drummer and singer in a particular band, then you don't have a choice: you have to record information at both levels. This will probably be an endless source of confusion in future

• The information as to what an artist did at an album or band level should be "what they generally did", not a comprehensive list of everything they ever did. Most people would say Ringo Starr was a drummer in The Beatles, not a drummer and singer, even if he sang on a few tracks. So when recording memberships of the Beatles, just give Ringo credit as drummer, and add his singing credits to the individual tracks to which they apply. This is to avoid adding duplicate information. It also provides a place to record the common-sense view of a band: otherwise Paul McCartney could be presented as drummer, pianist, singer, guitarist, and bassist in The Beatles, in that order, which gives completely the wrong impression.

Discussion:

• In "At which level do we enter AR's" mb-style list posting (Nov 2007), BrianSchweitzer argues that adding ARs to a Release as a way of saying they apply to every Track is more complex and therefore less desirable than adding ARs to each Track explicitly. First, some ARs are genuinely Release-level (e.g. photographer) while some are actually Track-level (e.g. composer). Second, it's likely that some ARs attached to the Release don't actually apply to each and every Track, just to some, and it will be complex to fix those. -- Summary by JimDeLaHunt 2007-12-18

• In Edit #7814443, BrianFreud (same person) argued at 2007-11-25 18:29:23 PST that the above proposal 'has pretty much been flipped to the reverse as preparations are made for track masters, which would require that to be reversed ("All information should be recorded at the lowest possible level.").' -- Summary by JimDeLaHunt 2007-12-18

• First a disclaimer: I'm relatively new at MB (one week) and don't understand every single bit in all its flavour. I think the goal should be a system where its possible to get maximum information (about a track perhaps) with a minimum of typing (entering information) effort. So I don't agree that it is the best to enter every bit of information at the lowest possible level. I have done this myself today half by accident on "Crash! Boom! Bang!". You can see every single track is written by Per Gessle and in addition track 12 is also written by Mats Persson. Second all tracks except track 15 are composed by Per Gessle where track 15 is composed by Marie Fredriksson. So instead of entering 31 single ARs it would be possible to enter just 4 and one "stop mask". Let me explain this: It would be possible to add one composing and one lyrics AR to the release crediting Per Gessle. Now we have 2 of the 4. Assuming we had full inheritance it would be sufficient to add another composing AR to track 12 crediting Mats Persson. So we would have both in composing track 12. On track 15 however we would need something what would sound in English like "except for track 15". Here I would like to introduce a thing I call "stop mask" for lack of better term. A stop mask would take a ARClass as argument. You could add such stop mask with the ARClass "composed on" to track 15. So any inheritance of "composed on" from higher levels such as release level would stop here. That said Per Gessle would no longer composing track 15. So you are able to start fresh from here and add Marie Fredriksson. Here are my 4 ARs and one stop mask to save me from adding 31 ARs. What I have in my mind to support this system are ACLs (Access Control Lists) on file systems. While POSIX did not have inheritance at all there are implementations in the good old Novell Netware where you have full inheritance of ACLs from higher directory levels to lower with help of such "stop masks" which stop inheritance. So you can give read rights for all users on some common directory tree, excluding some deeper directory in the same place per adding a stop mask. Further reading at this edit. -- AlexanderKiel 2008-03-03

Further to the mailing list discussion, I would like to add my unhappiness about a proposal to refer to Release-level performance ARs as "fuzzy". I don't have a problem with track-level ARs being "more important", but I've always applied release-level ARs when they are only true for the entire release, or at least according to the sleeve notes. Like Olivier and Lauri, I think the correct place for "fuzzy" information is in the release annotation. Editors should not be encouraged to add "performed guitar" to a release if one track only contains piano, but equally an edit should not be voted down if the Release level AR is entirely correct. --ArtySmokes

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