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Apple Music Matches Files with Metadata Only, Not Acoustic Fingerprinting (mcelhearn.com)
109 points by ingve on July 31, 2015 | hide | past | favorite | 56 comments

Uh.. pretty significant update to this post. Unable to reproduce.

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.

A lot of negative comments from people here, but I have to ask, have you used Apple Music and has this feature failed you? I didn't have any problems myself (not a huge collection, but it worked well for 24GB of songs).

Some people have mentioned that it can be easy to fool the system and gain free songs, but paying $9/month for Apple Music gives you access to every song either online or offline and you can add them to your library.

iTunes Match however is a different thing and they likely have to be almost sure the song you have is the song you should get access to from the iTunes Store.

My iTunes library is apparently 95.96GB (for music) and it's been working pretty awesomely. There's the occasional bug with iTunes itself, but Apple Music has been pretty solid.

> it can be easy to fool the system and gain free songs

I'm not sure what you mean by this. If you have Apple Music, you already have access to the entire catalog, so there's no trickery to gain "free songs", because they're already available. And if you don't have Apple Music, you can't do this either, because iTunes Match exclusively uses acoustic fingerprinting[1] to ensure you can never download a song you didn't already have.

[1] For non-purchased content. For purchased content they obviously already know you own it.

Yes, I wasn't saying it's a problem to 'fool the system' and get free songs, I was mentioning that it's not a problem because of how it works.

Plus if they used fingerprinting couldn't you still circumvent that with a youtube downloader or even torrent downloading?

If you do that, then you already have the song, so you're not really getting anything out of Apple that way (besides making it easier to play that song on your other devices).

I agree that people are very ready to point the finger at Apple when there is even a minimal issue. However, the very common use case listed in the article of uploading a live album and getting studio tracks, is more than just a minor annoyance.

I have 150GB in iTunes Match a lot of it live or remixes.

It definitely does do acoustic fingerprinting since I've never had or continue to have issues with my music being swapped out for something else.

It is the first time I've heard someone mention they got something completely unexpected, in a followup in the article the author mentions trying it again and being unable to reproduce it.

I hear other people having poor experiences. Here's one: http://www.loopinsight.com/2015/07/22/apple-music-is-a-night...

> have you used Apple Music and has this feature failed you?

Absolutely. I have a number of mix CDs (above and beyond, mainly) where apple music has apparently looked up the songs by title and artist only and replaced all the tracks in a mix CD with single versions of those songs, needless to say not mixed. I also have other songs which simply refuse to sync.

The article says: If you subscribe to both iTunes Match and Apple Music, then iTunes matches your songs using digital fingerprinting - but I thought Apple Music included iTunes match. Do I seriously have to sign up for another product as well to get this working? Not very impressed.

The best way to organize a mix in iTunes is to create a playlist with all of the songs, make sure the album title is the same for each artist, then select all of the songs and open the Info menu (CMD-I) and mark them as a Compilation. Marking them as a compilation will organize them on the file system together under the "iTunes/.../Music/Compilations/" directory, which hopefully will make migrating off of iTunes in the future an easier thing to do.

I've had metadata nonsense happen even with a set of just 100 songs. Had to correct everything manually in iTunes.

Yes, it has. It replaced live versions with album versions, non-censored (explicit) tracks with censored ones.

Apple’s been doing stuff like this lately all over the place. Total lack of attention. They’re trying to do too much too quickly and the attention to detail Apple is famous for is quickly dwindling. Please Apple, STOP RUSHING EVERYTHING.

They've acknowledged it and with OSX El Capitan and iOS 9 the focus is less on features and more on performance/polish. Remains to be seen whether they deliver or not.

Not to mention the poor integration between Music and the user’s existing library — its definitely not what I expected from Apple Music.

What poor integration? My entire library operates like it always has, except that viewing by Artists now has extra information about each artist in the list of albums, and also has a segmented control that lets me see all of that artist's music instead of just what's in My Music. And if I find a song I like, I can add it to my library pretty easily, at which point it shows up with the rest of my music just like all my existing owned music does.

Overall, it's actually working pretty amazingly.

It's not a recent phenomenon; you've just started noticing. for many years, Apple hardware has plagued by recalls, the website was wonky, etc.

I read some time ago (I think on one of Serenity Caldwell's iMore articles) that Apple Music uses metadata to match on iOS devices, because acoustic fingerprinting is too resource-intensive, but on the desktop it uses acoustic fingerprinting like iTunes Match has always done.

I don't know if this is true, but it does make sense. Although I wonder who actually has music on their iOS device that isn't also in iTunes on their desktop, because the only way you'd hit this is by adding an iOS device to Apple Music that contains music that iTunes did not have.

I didn't know you could use iTunes match from iOS devices but if Siri can be integrated with Shazam which has acoustic fingerprinting, then I would think they could do the same with iTunes Match on iOS devices.

You can't use[1] iTunes Match from iOS devices (for precisely this reason). It's Apple Music that you apparently can (I haven't tested but that's what I've heard).

Shazam does have acoustic fingerprinting, but it's much cheaper fingerprinting. And it's cheaper because Shazam is allowed to get it wrong. It doesn't have to get 100% of songs, and when it does get songs, it's perfectly ok for it to not recognize which particular performance a song is from if the artist has multiple versions.

But iTunes Match has to be as close to 100% accurate as it can (and better to avoid recognizing a song entirely, thus requiring it to be uploaded, than to mis-identify it as something else). Shazam is only listening to part of the song, but iTunes Match has to fingerprint the entire song, and the amount of processing it does per second of music may very well be higher as well.

[1] Where "use" means "upload music to"

Serenity Caldwell wasn't able to duplicate this, probably a bug.


I agree - it is most likely a bug. If not it seems like this would be a huge hole.

I've had a dozen songs across several albums exhibit this behavior. Never mind elaborate acoustic matching -- I've had fifteen minute live performances of a song replaced with three minute studio versions, which should have been prevented by a trivial metadata sanity check.

I haven't been thrilled by the experience.

Wow. If true, this is a massive flaw. I'm trying to think of a rationale for this approach considering they have the technology to match using the acoustic signature of the tracks.

Agreed. I like Apple more than most but... C'MON, GUYS! They've already got the technology in iTunes Match and it works pretty well. No clue why they didn't use it for this, especially when the whole "iCloud Music Library" is one of the bigger selling points of the service v. Spotify, Rdio, etc.

Last I knew, Apple licenses Gracenote's MusicID for acoustic signature matching in iTunes and iTunes Match, it's not technology they themselves possess. So perhaps the rationale is a licensing issue.

Maybe they can't spare the computer power to create an acoustic signature? How complex is the algorithm anyway?

By the way, I agree that the same song can be sung by the same artist in multiple versions, especially if it is a "signature song" for the artist. Just Acoustic vs. Rock beat can totally be different, and they are both worthy of having in your music library and not wantonly purged because the metadata is the same.

The acoustic signature would be generated by the client, then matched by the server. A bit more work than comparing tags, but not particularly onerous.

Not onerous? For what size libraries? For your iPhone? For a 3 year-old iPod Touch?

My iPhone 5 was trying to process photos in the background last night and my Twitter app stopped responding to touches. The keyboard was lagging by 30-60 seconds.

Are you sure acoustic signatures will not be particularly onerous?

iOS devices never need to generate those signatures, as there's no way to add new tracks to your iTunes library from them.

I'm consistently surprised at how often I hear about hacky, poorly engineered solutions in Apple products (and those are only the ones that are externally visible/relevant to product quality directly). I can't imagine they don't have access to broadly the same quality of engineer as other big companies, which leaves the question of why presumably deliberate product choices were made this way.

My guess is inflexible deadlines for products and a certain death march culture for meeting them (from what I've heard (third-hand, admittedly) from people who work there) lead them to be forced to cut corners in some places.

On the bright side, Apple does usually eventually fix or replace the hacky solutions. The other side of that is that it sometimes takes years.

Flaw in that you can match songs you down own or that the meta data might be wrong?

If they checked acoustic signature wouldn't it still work with illegally downloaded music?

Last summer, Sander Dieleman was working on recommending music based on audio signals, while interning at Spotify. Very interesting work:


Can't wait for a service utilizing this. I find finding new music hard.

iTunes Match would acoustically match songs, and then if the match failed, would just upload the song to iCloud as-is.

I imagine maybe this behavior is intended to replace uploading the song if the song doesn't match? It'd explain the situation in the quoted tweet where a live Phish show got replaced by a live recording, assuming that it failed to acoustically match and iTunes resorted to a metadata-based search instead.

Yeah, this is totally the case. I imported a CD awhile back which didn't have any metadata. Now if I try and listen to it on another machine, I get some odd indy artist who likes drums and screaming.

If this is true, you can create thousands of 1 second "songs" with different metadata and fill up your library really fast.

If you're paying for Apple Music you already get access to every single song in their catalog (like 40 million songs?) and can download them to your device. However it goes away once you stop paying your monthly fee.

If you want a bunch of songs or albums you don't have it's just a matter of search for it and listening to it, and to hit the 'make songs available offline' button.

Unlike Match, Apple Music will DRM-wrap the downloaded files, so it doesn't really get you free music.

Technical difficulty of stripping the DRM? FairPlay was easy enough, I'm sure this wouldn't be much harder.

If you're going to intentionally commit copyright infringement, it's probably easier[1] to just pirate the music than it is to download it from Apple and strip the DRM, especially because downloading it from Apple requires having a paid Apple Music subscription.

[1] Note: I do not in any way condone music piracy. I'm just pointing out that it's more practical than stripping DRM. But really the best thing to do here is to just pay for your music.

I was merely questioning it from a technical perspective.

I don't much care either way. People want digital content for free, publishers continue to rape the idea of works entering the public domain in a reasonable amount of time. Its hard to feel bad about either party.

I suppose if you're going to try to get around stuff, you can just torrent a whole library.

I had a ton of Apple Music problems initially, but I couldn't be more happy with it now. I love Apple Music. It screwed up the metadata all over my library, had problems with adding playlists to my library. It turns out it was all because there's no way to reset iTunes Match. The old iTunes Match songs in the cloud were screwing up everything. I had to use a second computer to delete the songs and create a blank library to Apple Music before all my music would sync to the cloud correctly. Apple really needs to get it together with their iCloud platforms. The amount of bugs is getting embarrasing. But Apple Music as a service is pretty awesome.

This also happened to me when I signed up to iTunes Match. At first it seemed everything was working properly, a lot of uploads as expected, but with time I realised there were some songs missing forever. Mostly bootlegs that were returning from the cloud as the original studio songs, I lost a lot of them. The most strange one was with Tool with the song "The Pot". The files on my iTunes were from the original CD and they all got a match but "The Pot" was returning as a 96kbps file! That was it, I stopped using iTunes Match that moment and will probably never sign up for any matching service again. Long live my several library backups in different locations. My library is sacred.

Forgot about this strange one: I own all System of a Down original and explicit CDs but iTunes Match got me the clean versions instead.

Lala (the iTunes match predecessor) at least took track length into account

Ahhhh Lala, forever missed! Among the best, and Apple shut them down. I gave up on my iPad and mac-book and went to PC after that let down. MediaMonkey and Spotify have my business.

Tangentially related to this, but I bemoan the fact that there's no portable playlist format. I have various services my music is on, and I wish there existed a playlist format that detailed every piece of metadata you had per song, such as file path, IDv3 tags, AcoustID, etc. That way, I could load the same playlist file on Winamp, Spotify and iTunes and have the songs available in each immediately, even if one was a cloud services and the paths were different in the others.

I have a particular hip-hop album on my phone that is an orchestra version of the original. Every time I attempt to play the studio album, I hear the orchestra (live) version. It's extremely annoying, and I hope they fix it.

I'm pretty sure they use audio fingerprinting (Gracenote MusicID has been cited) but using metadata with track lengths would probably suffice most of the time without too much piracy risk.

It's hard to imagine how such a huge oversight made it all the way to the final product from a company as huge as Apple. No one thought about this along the way? Or if they did they were ignored?

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