Apple Music Matches Files with Metadata Only, not Acoustic Fingerprinting

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.

Note: I have an iTunes Match subscription, which is active on the computer I used for these tests, so, theoretically, my tracks should be matched using digital fingerprinting. So I’m all the more confused about what’s happened here.

I started with a random piece of music from a disc of Bach chorales.

Match1

I changed its tags to Can’t Feel My Face, by The Weekend. (I picked this track because it’s one of the best selling tracks on the iTunes Store; I could have picked any track in the Apple Music catalog.)

Match2

I waited for Apple Music to match the file, deleted my local copy, and then downloaded it from the cloud.

Match3

Note that, so far, each version of the tracks shows a time of 1:57.

When the track downloaded, here’s what it looked like.

Match4

When I played it, it was not Bach.

Since Apple Music matches only using tags, it can’t tell the difference between, say, a studio recording and a live version of a song. Or an explicit version and a clean version. This explains why, for example, Macworld editor Susie Ochs found that a live Phish album was replaced by studio versions of the same tracks.

Phish tweet

Note that, in my example above, even the duration was ignored: a 1:57 track was “matched” to a song that’s 3:36. You’d think that Apple Music would at least use durations (within a few seconds) to try and figure out which version of a song is being matched, when there are more than one, but it’s not even doing that.

Here’s another example. I took a short speech from a Royal Shakespeare Company CD of excerpts from their current production of The Merchant of Venice. I labeled it “The Other One” by the Grateful Dead. It matched, I deleted the local file, and downloaded this live track from April 1971, which was released on the Skull & Roses album.

The other one

Granted, the track that Apple Music gave me is a great version of the song, but at 18:04, it’s far from the 1:25 original track.

This is a very big problem with Apple Music. Since Apple already has the technology to match tracks using acoustic fingerprinting, they should be using this with Apple Music. Instead, it’s using scattershot matching, which results in lots of tracks showing up as being from different albums, from compilations, or totally different versions of songs.

Update: 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.

Update 2: Monday morning. After someone on Twitter said that the above problem is happening to them, I tried again, and was able to reproduce it. As in my original experiment, I took a track, changed its name, and it got matched with the tracks whose name I entered in the tags. I downloaded it, and it was, indeed, that second track. I’ll keep looking into this.

38 thoughts on “Apple Music Matches Files with Metadata Only, not Acoustic Fingerprinting

  1. Thanks for verifying, Kirk. So disappointing to see that matching is tag-based only. Why would Apple differentiate matching between Apple Music and iTunes Match? Maybe cost-prohibitive, licensing-related, or a reason to keep the products separate?

    The fact that critical parts of Apple Music (playlists, off-line playback) require iCloud Music Library to be enabled makes the decision to cancel after the trial so much easier. If Apple Music ever starts using fingerprinting for matching, I would definitely be back on board (well, probably).

  2. So it doesn’t use a lot of the tags, apparently. For instance, it doesn’t appear to use track number, track count and duration, or other _intrinsic_ data that could better identify a track.

    • I would really expect that the duration would be used, but, as you can see in my examples, it’s totally ignored.

  3. Hi Kirk. Haven’t turned iCloud Library on on my Macbook since iTunes was updated (it’s on on my iphone and ipad though). I’m a long time happy Match subscriber. To make sure I don’t experience these issues can I turn iCloud Lib ON on my Mac without Apple Music ON in settings and have Match work as it always has?

    To test my understanding, is it the case that any Matched songs that were OK prior to Apple Music will still be OK with iCloud Lib enabled as long as I don’t delete and redownload any tracks even if Apple Music is enabled?

    • I don’t really know about that one. It’s really iCloud Music Library that’s messing things up. If Apple Music isn’t on, you won’t be adding anything to your previously called iTunes Match, but I’d make a full backup before trying.

  4. Thanks for the post. Another example of why I am not turning Apple Music off.
    I have another question about old iTunes Match users: I have iCloud music library on, because that seems to be only way to get iTunes Match style ability to download my tracks from cloud. I have apple music off. Have you experimented with this setup? Is there any other option for downloading my iTunes Match files at will and not using apple music? Thanks!

  5. Ok…my turn to rant. Please indulge me as I am REALLY getting tired of these Apple Music articles. This is not directed at Kirk so much as it is a common thread I see in almost all the articles I read critical of the way Apple Music works is around the issue of track substitution for those who are, for lack of a better term, audiophiles.

    First…almost comically these same writers, many of whom make a claim to be technology experts, pundits, or bloggers, seem to have forgotten the most basic of back-up and recovery of their data. The web is filled with “experts” who are angry, incensed, and critical of Apple because they are missing some tracks or versions of particular songs.

    Yet while all claim their music libraries are seriously important to them none of these individuals seemed to have prepared for a hardware failure never mind following the cardinal rule of back-up before you upgrade. In a world full of back-up solutions, local and cloud, I have ZERO sympathy for anyone that loses something so important to them that they take to the interwebs to express their frustration but can’t buy a $99 USB drive and copy their Music over…I won’t even mention Time Machine.

    I do know that I have 24,000+ tracks in my iTunes Library. I know that I had issues with iTunes Match i the early days. I even once hit the song limit and all $#@! broke lose on me such that I had to delete my iTunes Library from the cloud and locally to solve. Thankfully I had a number of backups all the way to the old MP3 files and was able to rebuild everything fresh with no loss of my music. From that day forward iTunes Match has worked pretty much flawlessly!

    In the case of Apple Music, thus far I haven’t experienced any issues, or at least with 24,000+ songs I haven’t found any yet. That may be related to my particular library more than Apple Music. To stay under the iTunes Match limit I long ago archived multiple versions of the same song picking my favorite and placing the others in a “Additional Music” library.

    So…getting to my real point… regardless I am more a typical music customer than an audiophile. I’m not doing to post rants to the web like I’ve seen lately about things like bit rate when I know that in my car, where I most listen to music, the head unit and speakers aren’t good enough to perceive the difference anyway. Not in my E350 or for sure not my Boss 302. I know that my patio speakers outside where I play music during parties and people are talking, screaming in the pool, are also use cases where bit rate is not going to be a deal breaker. While I am driving I’m not likely to, nor would be very safe, to demand a specific version of a specific song even if Siri could figure it out. I also don’t think my party friends will much care either.

    Now rant over…I think FOR SURE there are issues with Apple Music just as there are all 1.0 products. I am just as sure they will be resolved. If you back-up, read articles such as this that try to help explain what’s going on, iMore has some great articles too, you can prevent issues at best or remediate them at worse.

    As for the article here and how specifically Apple Music matches songs I can see definite issues with this and as more issues are found I would expect to see Apple adjust the algorithms. I can also understand the burden and compute power needed to do what iTunes Match does for the estimated 10 Million active demo users on Apple Music. It simply may not yet be possible for Apple to do what some are asking of it. I have no idea but Apple being Apple they’ll figure it out because it’s as important to them as it is us.

    Thanks! I feel better now.

    • I completely agree with you. Before I jumped into Apple Music with my 200K+ library, I read the great iMore articles to understand the best way for me. I split my library. One into 24K songs that I really loved and the rest in a separate library. Then joined iTunes Match and it uploaded the 80GB of un matched music in the primary library. Then joined Apple Music and turned on iCloud Music. Not a single problem between four devices. I even added a new album from Bandcamp today, and it was available on all my devices in 5 minutes.

      Oh, I have 4 copies of my library. lol.

  6. Even more weird, for “Can’t Feel My Face”, the artist is actually “The Weeknd”, not “The Weekend”. Strange that it was still incorrect even after downloading…

  7. This seems like an easy way to get a lot of music that one hasn’t paid for. Couldn’t you just duplicate a small MP3/M4A file many times, add Artist/Song/Album info to the files representing all the music you wished you owned, wait for them to match, then delete the dummy files? If I understand the post correctly, Apple Music will now download the real versions of these songs. Seems like a real hole in terms of not allowing piracy!

      • Ah, so the Apple Music Match feature is really just a way to batch download songs from the streaming service for off-line listening, but not really providing anything over and above what you could do manually with the streaming service anyway. It’s not a cloud storage solution like iTunes Match. Apple Music is certainly a very confused product offering!

        • That’s correct; sort of. It is still supposed to match what’s already in your library, but it provides DRMed tracks if you don’t have an iTunes Match subscription. Yes, it is confusing.

          • But you mentioned that you DO have an iTunes Match subscription, so why did these tracks match by Apple Music and metadata and result in files that have DRM, in the first place?

            Shouldn’t they have matched via iTunes Match regardless?

            Or is that the temporary glitch that has been resolved?

            “Confusing” is right!

            • Yes, that’s clearly a bug, and one that I have not been able to reproduce. But the matching by metadata without an iTunes Match subscription is the way it’s designed, and it can turn up surprises, such as the Phish example, where live tracks (presumably matched on a computer) show up as studio tracks elsewhere (presumably on an iOS device).

  8. Have you considered that music copyright owners may be negotiated the licenses with such restrictions to force control on streaming music that the labels did not have in the non-streaming iTunes Match case? See the imore discussions about licensing for Apple Music.

    • Of course, and the fact that Apple Music files have DRM is normal, considering that they’re tied to a subscription service. But that’s not at all what I’m discussing here.

  9. I’ve been “struggling” myself with this one song—and I’m not complaining, but I can’t figure out what Apple Music did here. Also, I had/have iTunes Match, as well.) This one song was a studio song, and after turning on Apple Music, it was replaced with a track that has a DJ at the beginning and end. I downloaded Apple Music’s copy, made a copy, removed the download, purchased a copy from the iTunes Store, and there’s my original studio cut. It also (jarringly, while I was in the folder) moved the track out of Compilations, /and/ the purchased copy has different metadata (including the complete title: subtitle, versus my main title-only).

    • Sorry to reply to my own post, but I think the question I’m not sure the answer of is, if Apple Music used metadata to match the song, it should have kept the correct cut, right? It sounds like a chance fingerprint mismatch that used a middle segment of the song, but your tests obviously show a switch to preference/reliance on the metadata now. Both tracks have the same track number, duration (within a second), artist, roughly same album title. I did own the CD at some point, so it was previously an iTunes Match-matched track.

  10. Thanks for this article.

    One thing which is implied by this (and other articles) is that your original music files are somehow in danger. I think it’s worth pointing out that this is only if you delete the original file. I keep my original master music library at home, and its files continue to be correct (and DRM-free).

    My music in the cloud has matching mistakes of course. But 95% of it is correct so it is perfectly usable, just very annoying when I hit a problem track.

    I agree that tag-only matching is lame. In theory you could use it to correct bad matches manually. Unfortunately when I tried editing one of my files to match iTunes, the bad match remained in the cloud. Once its matched to anything iTunes doesn’t want to rematch it. (At least give me the option to retry it, Apple!)

    If Apple isn’t going to get the matches 100% correct then at least they should give us tools to fix the problems. At the moment we’re stuck without even a good workaround, which is one reason I think people are so very frustrated. But it also seems like it wouldn’t take much from Apple to fix this. Thank you for helping shed light on the problem!

    • Yes, your original files are not touched at all. If you delete them, then you get what’s in the cloud. But the problem arises if, say, you have a Mac and you match your library, and you then try to listen to it on your iPhone. If tracks are matched incorrectly, there’s no way for you to get the original tracks on the iPhone, unless you turn off iCloud Music Library and sync.

      • Yes, exactly what happened to me. Very annoying. For some music collections the cloud service is unusable.

        But I’m seeing people linking to your post with the fanciful headline “Apple Music will literally destroy your music collection”. And one blogger concluded “Don’t let Apple Music anywhere near your music library.” So I thought it was worth clarifying.

  11. I’m not sure if this is all that is going on.

    I’m a long time Apple Match user and have not activated Apple Music yet.

    But *something* has happened to my Music library in the last few weeks since Apple Musica launch. On my home iMac (the original source of truth) everything seems fine. All the tracks, metadata and artwork is fine. It’s also backed up so I’m not to concerned.

    However, every other device that accesses that library through Match (iPhones, iPads, Apple TVs) is looking at a corrupted version of the library.

    I have multiple copies of the same artist appearing, often splitting an album (e.g I have two artists both called Queen. Half of an album will be on one ‘artist’, and the other half on another ‘artist’).

    Additionally, some tracks have been assigned to an artist that appears to be derived from the metadata (e.g it now lists an artist who is a band member who wrote the song rather than the band)

    And I have another group of songs who have been assigned to random artists who have nothing to do with the song (mainly Fred Astaire!)

  12. First of all: I don’t think that this behaviour is good from a customer perspective.
    I think Apple only looked at this from a “copright”-perspective.
    Then it makes sense:
    – with iTunes Match they want to avoid that people are just renaming files and getting DRM-free ‘kind-of-legal-versions’ -> that’s why they use fingerprinting with iTunes Match
    – with Apple Music it doesn’t matter, the only goal of matching is to provide an easier migration from your local music collection to their streaming service. Otherwise you would have to manually search for your music and then manually add them to your Apple-Music library. So instead of typing in ‘metallica master of puppets’ in the search field Apple Music does this for you. It also just ‘enters’ the search string (which is the metadata) and is adding the music to your library. As long as you have your subscription you have access to all the music anyway. So there is no need to use ‘fingerprinting’ from a copyright perspective.

    Anyway, from the user perspective it doesn’t make sense.

    • Fingerprinting proves that you do, indeed, have the exact same track. That’s important as far as rights holders are concerned. But I think it’s also important that, even if you’re not paying for iTunes Match, you get the correct tracks in your library.

  13. I’m using Apple Music, and an iTunes Match subscriber, and have been noticing this issue. In my case, I’ll be playing a playlist Apple Music recommends me, and if a track I have appears in the playlist, it’ll use that instead of the actual version the playlist has. Usually it means that when it should be playing a studio version of the track from a specific album, it instead plays a bootleg live version of the same song that I happen to have in my own library. It leads me to believe it’s only checking the artist and song title metadata, ignoring even the album title.

  14. I think the situation is more complicated. I have a 40 minute mp3 in my iTunes library with a mix of songs in a single file, named in such a way that none of the songs are identified. Using Apple Music on another device, the track shows up and when I play it, it consists of the first track in the mix (with the corresponding artwork). The only way this could have been identified is through acoustic matching — none of the metadata on the original file indicates the content. So it seems that Apple Music is trying first with metadata but using acoustic matching as a fallback.

  15. This thing is a headache and I have to pay extra for it? I’d rather keep the streaming separated so I can download files for offline listening. Not on Apple Music.

  16. I noticed this issue/matching behaviour from day one.

    I have a large number of live and remix tracks – lots of which have been mismatched with the album versions. The recent update did resolve the issue for a number of files, but not most of them.

    It’s very clear that the tags it matches are only partial as well. For example;

    I have a track (an mp3 in iTunes on my Mac) –
    Artist: Gwen Stefani
    Track: Hollaback Girl (Live on SNL) (05′)
    Album: The Neptunes.Org & DPSP Presents… Live Tunes

    Yet, Apple Music has matched the track with the album version of this song on all my other devices and over-ridden the completely different original album art as well. This shows that it’s matched the artist, partially matched the track, and completely disregarded the album name and artwork for any kind of match.

    From the data provided, the track is quite clearly not the album track and shows that even though Apple has taken the ‘easier’ option of tag/metadata-matching, the matching criteria is VERY low.

    This has happened throughout my library, although luckily it doesn’t affect the original on my ac, just those sent down from the cloud to my iPhone or iPad.

    • This (and other issues with the server) are driving me nuts – as always, if you dare creating your libraries outside of Apple’s closed garden ecosystems, frustration and problems awaits..

      To make matters worse, Apple’s usual radio silence on their product’s issues makes one wonder if the issues are a) heard, b) acknowledged and maybe even c) being worked on..

  17. I am struggling with this same issue. All my live bootleg cd’s are a disaster. None of them from the album I wanted to have uploaded. I am an iTunes MAtch subscriber and am on the trial for Music right now. Can I cancel Music and just use Match still?

  18. Better late than never, but I just found this. I can verify this issue and that it is due solely to Apple using metadata.

    I transcoded over 800 CDs from FLAC to ALAC (in M4A containers). I have the soundtrack to “Mary Poppins” and the first track is titled “Overture.” It’s 3:01 in length. I added it (and all my other music) to iTunes, then played it through Sonos and, instead of “Overture” for “Mary Poppins”, it played “Overture” to “My Fair Lady.” It was the same title and the same length (3:01), but it wasn’t even the same freaking album! I tested and found if I played this song on iTunes, on my iMac, where the file exists, it plays the proper version of the song. But on *any* device I have (Sonos, iPad, iPhone), playing it would give me the song from “My Fair Lady.” Also note that is NOT a song I have in my collection. It’s pulling it straight from Apple’s library.

    So I removed the song from my iTunes library, leaving the original M4A file in place on the hard drive. Then I edited the tag and changed the name from “Overture” to “Overture (Mary Poppins)” and re-added it to iTunes. The ONLY thing I changed was the title in the metadata. Once I did that, I went to my iPad and to Sonos to test it out. In both, the title was now “Overture (Mary Poppins)” and the correct song played.

    All I did was change the title in the metadata and that was enough to make sure iTunes used the right song.

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