Apple Music Matches Files With Metadata Only
If you’ve used iTunes Match in the past, you may know that it matches music using acoustic fingerprinting, which means that iTunes scans the music, and matches it to the same music. It doesn’t matter what tags files have: you could have, say, a Grateful Dead song labeled as a song by 50 Cent, and iTunes Match will match the Grateful Dead song correctly. (Here’s how Wikipedia defines acoustic fingerprinting.)
Apple Music, however, works differently. It does not use the more onerous (in time and processing power) acoustic fingerprinting technique, but simply uses the tags your files contain. And it can lead to errors. Here’s an example of how this can be a bit surprising.
Update (2015-07-31): Marco Arment:
This is embarrassing. No wonder people have had so many problems and so much data loss with Apple Music’s cloud-library features.
It’s as if nobody who made this implementation decision had ever encountered remasters, re-recordings, clean versions, live performances, or the many other extremely common reasons why two very different audio recordings might have the same artist and title.
[…]
Don’t let these cloud-matching “features” anywhere near your music collection.
Update (2015-08-01): Kirk McElhearn:
I’ve been unable to reproduce this issue, and my guess is that there was a glitch with Apple’s servers that has since been corrected. If you only subscribe to Apple Music, or are using it on a free trial, then your songs are matched using metadata only. If you subscribe to both iTunes Match and Apple Music, then iTunes matches your songs using digital fingerprinting.
That this happened at all (and I got reports from many other people who were affected) means that iTunes Match is less trustworthy as primary storage, and it never really was trustworthy as primary storage because it has always been buggy and inconsistent, so my recommendations remain to avoid letting these features integrate with your music collection.
Apple’s been doing Match (as have other companies) for four years now and none of them have it anywhere near perfect.
I wonder if matching is still the right choice. I bet most people’s music libraries are smaller than their photo libraries.
Update (2015-08-03): Kirk McElhearn:
FYI, I was able to reproduce the change-the-metadata-and-match thing in iTunes this morning. I made a screen recording of it.
