I’m not aware of any guidelines for merging recordings accept for: https://musicbrainz.org/doc/Edit_Types/74 and there are often heated discussions in the edit notes about what is enough evidence to merge recordings. E.g. tonight I got about 60 emails from edit discussions between @jesus2099 and @dragonzeron. I think it would be better to discuss this in the forum.
So I’d like to share my personal guidelines and see what you think about them.
I have three rules for merging recordings (either so I will merge or I will vote yes):
- There can’t be any obvious contraindications (e.g. different artist, recording title, length, recording disambiguations or even album disambiguations [e.g. one is clean the other explicit] or e.g. one is on a DJ mix).
- if you can plausibly explain why it’s still the same recording even with e.g. different artists credited, then go ahead, but describe it well in the edit note.
- There has to be a clear evidence that they are the same recording. That means either:
- same album, or one is on a box set including the other album or one is on an associated single/EP, …
- same ISRCs and no contradicting AcoustIDs
- only matching Acoust IDs, or most AcoustIDs match
- you have both mediums and confirmed they are the same recording by listening.
- they have disambiguations that clearly indicate that they are the same (= "live at XY on YYYY-MM-DD - sure there is still the slight chance that the artist played the same song twice at the same concert like Les temps changent on this release).
- If 1+2 are a match then its relatively safe that the recordings are the same, but there still might be differences, so if anyone has a plausible concern you should cancel your edit.
What doesn’t count as clear evidence to me (I won’t merge or will abstain):
- recordings share one AcoustID among many AcoustIDs involved.
- recordings are on Various Artists compilations (many of those don’t have the correct extra title information so you might be merging clean and explicit versions or a longer and a shorter version that only have 3 seconds of difference. One of the VA compilations might even be a DJ mix and it’s just not marked as such).
- recordings have the same extra title information (sometimes a remix is more popular than the original and a compilation might have a title called “Song A (radio edit)” when it’s actually the radio edit of the remix.