User:LordSputnik/Recording Style Guidelines (Version 2)
This proposal is designed to improve the guidelines on merging recordings. It is felt that the current guidelines are too vague, and that they don't cover all cases where recordings might be merged. This proposal seeks to expand these guidelines and make them clearer.
Edit http://musicbrainz.org/doc/Style/Recording to change the section "What should and shouldn't be merged together?" to the following.
A recording is intended to represent a unique audio source. This means that generally, two tracks should only share recordings if the audio source used to create them was the same. An audio source is considered unique as soon as any changes make it different from a previous source.
- If multiple performances of a single work are recorded and released then each performance is a separate audio source, and each released performance should be given a separate recording.
- If several tracks contain recordings of a single live performance of a work, each track that was recorded by a separate device is from a separate source and should have its own recording.
- If a track from a CD or any other digital medium contains audio that was originally recorded and released in an analogue format, the digital track should not use the same recording as the analogue track. The original analogue source was changed when it was converted from analogue to digital.
- If digitally recorded and mastered audio is originally released in both analogue and digital formats then the tracks containing that audio should share recordings. The audio source for all tracks is the original digital recording.
- If two tracks from different versions of a release are mastered in audibly different ways, then the source has been changed for each mastering, and each track should have its own separate recording.
- If a track contains audio that is remastered from an earlier recording, the track should be given a new recording. The source was changed when the audio was remastered. If another remaster is made, then the source has changed again, and another recording should be made.
- If a recording is edited or remixed, the new track should have a separate recording. The exception to this case is for changes that only affect the length of the fade at the beginning or end of a track, where a new recording should only be used when the difference in length is greater than 10 seconds.
In addition to these cases and the general guidelines, recordings with multiple, visibly different AcoustID fingerprints should not be merged. Instead, the recordings and AcoustIDs should be examined for correctness.
In theory, recordings which have different sources should be assigned different ISRCs. In practice however, this doesn’t always happen. Recordings with different ISRCs should be examined closely to determine whether they are actually different. Similarly, recordings with the same ISRCs may in fact be different, so care should be taken before merging them.