iTunes Match: Everything you need to know

iCloud is Apple's new service for keeping iOS devices synced over the air. One of the coolest features is how you can instantly download your music to a mobile device, instead of being at home and syncing a playlist from your computer with a boring old cable.

Any music bought on iTunes will be available from your iCloud automatically, letting you download tracks at any time. But what if you haven't bought your music through iTunes? That's where iTunes Match comes in -- it's US-only at the moment, but we're expecting it here in the UK in early 2012.

What does iTunes Match do?

Many people's digital collections began with a stack of CDs being copied to computers. You might have taken part in the legally dubious Napster revolution, or shared your entire iTunes library over a Wi-Fi network as a student.

iTunes Match is the solution to this -- it scans your music library and compares it with the 20 million songs available on iTunes. Any matches will then be available to you for instant download on any of your devices, anywhere.

Whenever it doesn't find a match, it will upload that song or album to your iCloud account so it behaves like the rest of your online library.

Nothing happens to your local library when you run iTunes Match, though after running it you can choose to delete music from your hard drive knowing it's available for instant download in the future.

This potentially useful new service costs $25 per year in the US, so we expect a price of £20-25 once it arrives in the UK in the next couple of months. Some of this money will go to the major record labels, as a kind of 'piracy tax' to recognise that not all MP3s have been legitimately acquired in the past.

Assumed guilt aside, it's a fair price for a useful service, and it might even save you a few quid on your next Apple purchase. Rather than buy a 64GB model to store your full music library, you could buy a smaller version and instantly swap albums on the go.

Is there a catch?

Match will only scan up to 25,000 songs, which is about 2,000 albums. This won't be a problem for most people, but we imagine there are a few students and torrent abusers with a handful more than this limit. There's a long-winded workaround, but now is a good time to be realistic about what you listen to and trim your library down to size.

You can use Match once per year, so any CDs or non-iTunes downloads you buy in the meantime can eventually be added to iCloud too. If you choose not to continue paying the annual fee, you'll be blocked from downloading your tracks from iCloud. Grab a cheap hard drive and keep your library backed up in case you change your mind one day.

Finally, if you listen to music with explicit lyrics, some Apple forum users report that some albums might be matched to a clean version by accident.

What quality are iTunes downloads?

Any songs re-downloaded from iCloud will be in the iTunes AAC format. This is Apple's version of MP3, and it's perfectly good, but be warned that they don't work on every music player. Of course, if you own a Microsoft Zune, you're probably not that interested in this service anyway.

The bit rate of these AAC downloads will be 256kbps. Bit rate is to audio what resolution is to displays, and 256kbps is perfectly good, unless you have speakers worth more than your monthly rent or think God gave you special ears. If this is the case, make sure you keep your special high-res audio backed up somewhere safe.

iTunes Match won't work with certain low-quality MP3s below 96kbps, though you probably don't have any. Music saved at this rate is the equivalent of watching Avatar on a Gameboy. But if you do, these files aren't a lost cause -- just use iTunes to convert them to any old AAC and iTunes Match will now recognise them. Once matched, you can choose to replace them with the higher-quality iCloud version.

What else should I know?

Tracks matched to iTunes will keep the same metadata, which is things like the track names and artwork. Once this metadata goes online, it sticks -- even when you re-download a version from iTunes. If you like everything to be accurate, get tagging now or use a plugin such as TuneUp to keep your jukebox tidy.

iCloud will stream songs over the air to your computer, just like Spotify. It might appear to do the same thing on iOS devices, but in reality it downloads a copy and starts playing the song once it's buffered. So while it appears to stream in practice, it's really taking up storage space as if you downloaded it anyway. No game-breaker, but worth knowing if your device is jam-packed with apps.

You can only sync your library to one account, so you can't jump on a friend's computer and sync their tunes too.

Sounds easy! So I just get an iCloud account, right?

It should be that simple, but unfortunately it's not.

Apple fell into a confusing account system where lots of people were buying from an iTunes account for years, then later signed up for a new MobileMe or iCloud account so that email would push to their iPhone. You'd think these accounts would merge for a seamless "just works" Apple experience, but nay.

We hear Apple is working on a merging solution, but in the meantime we recommend using iTunes Match on whichever account you buy your music and apps with. This won't apply to newer Apple users, who will probably only use one iCloud account.

If you're still unsure, check Apple's official FAQ on the issue.

iTunes Match is yet to launch in the UK, but it's not far off now. Are you looking forward to cable-free music syncing, or would you rather manage your library on your own terms? Let us know in the comments, or on our Facebook and Google+ pages.