Now available for those who would like access to all their music on the road.
I see this as a handy tool - even my 64GB iPad2 doesn't hold quite all the music I have in my iTunes catalog, and my 8GB nano isn't even close (though I realize it won't help that).

But a question:

It appears that I can basically replace everything I have purchased, ripped, or downloaded elsewhere with 256kbps versions on my PC - though not automatically.

So I'm curious as to how Apple will know that a track I have is valid. It says it won't match <96kpbs files, >200MB files, DRM files not authorized to that device But if I copy an existing file and rename it "Texas Flood.mp3" and put "Stevie Ray Vaughn" as the artist and "Texas Flood" as the album, how is Apple going to know that's not what it is?

Doing actual matching via the track contents would seem to be compute/network intensive. But if that's not done, I could basically make up 25,000 songs that I want via editing, match them, and download them. Is there metadata embedded within an mp3 file, encrypted/tamper-proof, that would prevent this?

One downside - when you replace files with 256kbps versions, they are AAC, even if the originals were mp3's.

I read the attached article -- good grief that's a lot of explanation and instructions. Which is why I use Google music, which involves:

1) Download a small app
2) Point it to your music folders and upload them
3) Access from anywhere via http://music.google.com
4) Pay nothing.

I don't think they will tell us exactly how the match will work, in my case it matched most of the stuff I ripped myself, (vbr, avg rate ~200kbps) or bought from amazon but there are some odd exceptions, like one track from Abbey Road (though it matched all the others and they were all ripped at the same time, using identical settings, ...) and lots of things like that. I'm sure you can find some articles on the match and how people think it works. I kind of doubt you could edit a file and create a fake match yourself, but, sure, you can try I suppose.

You don't have to replace the tracks in your library where you ran the itunes match. Presumably you have one master library? That's what I have, I just ran it there, but I'm sure I still have the original flac files somewhere if I really need them or want them. Didn't you rip to a lossless format?

Anyway, if you want to "upgrade" the tracks in your original library, you can, but it won't do it automatically. (as you noted). Here's another article describing the process, the one I used which is much simpler:

http://www.macworld.com/article/1636...atch_fast.html

Anyway, it worked fine for me. The cloud was up and down a few times when I was trying to download the matched 256kbps AAC versions, so that was pretty weird too.

-David

Lot of steps only if you want to customize otherwise it involves zero steps. Ok 1 step - turn it on.

Added some other conditions for clarity.

I might have missed/misinterpreted some of them but my eyes glazed over after the 8th paragraph.

Good grief their DRM looks even more asinine now. I guess we get to rebuy the music when our authorizations run out and the devices die. UGH.


Google Music has some irritations but far superior to iTunes.

It uses acoustic fingerprinting. I believe the songs are analyzed on the client side, and the fingerprints are sent to Apple. Same as iTunes genius and apps like Shazam.
http://en.wikipedia.org/wiki/Acoustic_fingerprint

Re: Google Music
There are some that like "free". There are others that are willing to pay to have integration and good design. Examples I'm familiar with are home automation tinkerers like X10/zigbee/Zwave, others like Bang & Olufsen who have done it for years, works pretty well, but charges a lot.

I prefer the system that integrates with our existing 4 iPhones, 11 Macs, and 6 Apple TVs.

If you ever have to use products other than Apple iTunes is light years from good design. Sorry, as an iCloud user I don't get it. It's a weak service.

It's not that intensive; Shazam for iPhone and Android can match a song in a noisy bar with ten seconds of recording out of a collection of 20,000 songs in less than half a second on a normal desktop computer[1], and iTunes Match has a "radio quality" sample that Shazam's algorithm could do in a hundredth of a second. Additionally, they can fingerprint over the whole song (with a similar number of samples as Shazam's ten second fingerprint), allowing for a better match with less randomness.

1: http://www.ee.columbia.edu/~dpwe/pap...g03-shazam.pdf

I guess it depends on your definition. To match my 15,000 songs, listening to 10 seconds of each song would take 42 hour of processing. And iTunes has slightly more than 20,000 songs (20 million), and I doubt it's linear. And the database isn't local.

I'm sure Apple has thought of this and suspect that a sample/hash/metadata is probably already embedded in the file so it's nothing more than a signature match with the claimed title/track/artist. I doubt it does a pattern match against the entire catalog if the signature doesn't match - probably just uploads the track for your use but doesn't add it to the master database for other users.

Or something completely different.

I have about 10K songs. This all was done very quickly for me. I also set up a smart playlist in iTunes to find all the songs I had that were at a quality lower than 256kbps. Many songs of mine (ripped from old CDs) had to be re-downloaded in order to get the higher quality. Every last song of mine was matched/downloaded and the process may have taken 2 hours or so.

Key thing is that now all my music (and not just a smaller playlist) is now available to me on my iPad and my iPhone.

8th paragraph of what?

If you just want to use icloud and music match, you just turn it on. That's all you have to do.

If you're interested in upgrading the quality of some of your low quality tracks that were matched, then read the article in the link I posted. Otherwise, ignore it. It's certainly not required.

There's nothing wrong with google music, but it just doesn't integrate as well in ios devices. I hope it integrates better in android devices.

It's a fine service, I have both. Now that music match is here, google music will be a backup for me on the ios devices. And I would say that if you aren't an itunes user or ios device user, there's really no reason to use the music match service either. amazon or google would probably be a better choice for you. (at least until Amazon starts charging for it.)

-David

but, if the music is ON that machine then it is most likely authorized anyway otherwise it is just a useless file sitting there.

on nice thing about the itunes match implementation is that there really is NO upload except for the files that it cannot match.

They don't have to decode the song in real time to sample ten seconds; my 2009 MacBook can decode a 15-minute MP3 from a 5200rpm mechanical drive in three seconds (see the "2.656 total" at the end of the last line):I'm sure checking the database isn't linear; it's probably logarithmic, which is faster than linear. The database isn't local so there's latency, but Match batches up requests and doesn't wait for the previous song to be finished analysis before churning on the next one.

Doing a signature match on the metadata isn't workable, since many people have absolutely terrible metadata. It can't be done from a precomputed sample in the file because then pirates will just distribute collections of empty files with correct samples. It has to be done over the whole file, and it has to be of a bitrate high enough to make piracy for the sake of matching less practical for most people.