Are CD's ripped with iTunes AAC less portable than MP3s?

February 3, 2004 9:12 PM

If I rip my CDs with iTunes, and select the "AAC Encoder," will the files be any less portable than MP3s? Can most MP3 player apps/devices handle them? Are they all intrinsically copy-protected? Are there real quality benefits? (I'm asking on behalf of someone who has already invested serious time in ripping, using iTunes' - you guessed it - default settings).
posted by scarabic to technology (15 comments total)

will the files be any less portable than MP3s?

Yes. Only devices that can play MPEG-4 audio can play them.

Can most MP3 player apps/devices handle them?

No, just the iPod currently.

Are they all intrinsically copy-protected?

No, only the ones you get from the iTunes Music Store are protected.

Are there real quality benefits?

At the default bitrate of 128Kbps, definitely. Less so at the higher bitrates, because AAC is optimized for a sweet spot around 128Kbps.
posted by kindall at 9:20 PM on February 3, 2004

excellent, thanks kindall
posted by scarabic at 9:23 PM on February 3, 2004

Marc Heijligers did a shockingly detailed comparison of sound qualities of AAC and MP3 files at six different bitrates (each). Basically his conclusion was that yes, AAC files have a real quality benefit.

But as Kindall said, only the iPod plays them, of portable MP3 devices so far.
posted by Aaorn at 9:34 PM on February 3, 2004

Ouch. My girlfriend did the same thing.

My suggestion? Convert them to MP3. You won't lose much quality as long as you encode at a high bitrate, like 192kbps or above. Easy CD-DA Extractor has handled nearly anything I've thrown at it, including AAC (M4A) files I ripped with iTunes.

Of course it would be better to rip them all over again... but if you don't want to invest the time, and can sacrifice a little quality, just convert them.
posted by bhayes82 at 9:47 PM on February 3, 2004

There's an aac plugin for Winamp.
posted by stavrosthewonderchicken at 10:50 PM on February 3, 2004

Interestingly for me, I just spent 8 hours driving in my car to get to this particular person, and I have not spent so much time listening to regular CDs (that's all my car will play) in a looong time. Certain discs really brought home the joy of uncompressed music as I'd never realized I missed it. Whew. A friend's Tortoise mix coming through the Grapevine was definitely the highlight. I'll have to rethink this whole "portability" thing ;)

Just kidding (though I may have settled a long 128 vs. 256 debate, at long last) and thanks for the helpful comments, all. Luvyas.
posted by scarabic at 2:13 AM on February 4, 2004

There are some OSX AAC tools at versiontracker:

versiontracker AAC tools
posted by mecran01 at 5:52 AM on February 4, 2004

I would never ever recommend re-encoding from a lossy format (i.e. making mp3s from aacs) as you would lose a lot more detail than you had lost initially.
posted by gen at 6:53 AM on February 4, 2004

That MP3/AAC comparison is interesting. A while ago, I read an MP3/CD comparison (sadly, 404 now) that made the point that, with a good encoder, 192 kbps MP3 was essentially indistinguishable from the CD original.
posted by adamrice at 6:55 AM on February 4, 2004

I too ripped a bunch of CDs in iTunes before realising that the default was AAC, but then I realised that I had been listening to CDs made from those rips on a variety of CD players (including my 9-year-old POS AIWA mini boombox), and hadn't noticed a damn thing.

I have been converting between AAC and WAV when I need to burn a disc now though.
posted by terrapin at 7:40 AM on February 4, 2004

Incidentally, it's possible to use iTunes 4.x itself to convert AAC encoded files to MP3. Go to Preferences, and on the Importing tab set "Import Using:" to "MP3 Encoded." Set the rest of your preferences for how you'd like the MP3 files to be created and click "OK."

Now, in any view of your Library or in a playlist, select the AAC files you want to convert. Choose "Convert Selection to MP3" from the "Advanced" menu and voila! MP3s!

(I ripped an entire ten-disk set of Beethoven piano sonatas to AAC before remembering I'd wanted MP3s. I'm sure from a technical standpoint the quality of the MP3s is not as high as the AACs, but I think it takes something of an audiophile to hear it.)
posted by JollyWanker at 7:58 AM on February 4, 2004

What Kindall said, that smart cookie. Here's what we said about AAC in MWJ way back on 2002.02.13, when QuickTime 6 was released and iTunes Music Store was just a glint in Steve's eye:

Discussion of audio encoding rapidly moves to a dimension only true signal processing wonks could love, so pardon the traditional oversimplification. MPEG-1 Layer 3 audio, now known worldwide as "MP3," is the third lossy compression scheme approved as part of the MPEG-1 specification; Layer 1 and Layer 2 weren't quite as good. Still, MP3 is about ten years old now, and there are more capable lossy compression formats available. Advanced Audio Coding (AAC) is pretty close to the state of the art in lossy audio compression, and is part of the MPEG-2 specification. It can handle anywhere from one to forty-eight channels, fifteen low-frequency enhancement channels, fifteen embedded data streams, and even multiple language capability. AAC is sometimes referred to as "MPEG-2 NBC" because it is "not backwards compatible," unlike MP3's design that included playback of layer 1 and layer 2 audio. Because the designers could break that chain, AAC goes in new directions that previous MP3 decoders could not handle.

The result is an encoding standard widely considered to be either the best or among the best lossy audio compression systems available today. The goal of AAC (sadly, 404 now and not in Google's cache) was to deliver five full channels of audio that, when encoded at 384Kbps, would be indistinguishable from the source audio to trained listeners. Testing in 1996, AAC's developers got the "indistinguishable" rating at 320Kbps, where MP3 needs anywhere from 640Kbps to 896Kbps to get the same rating. At lower bitrates, AAC audio at 128Kbps is as good as or better than MP3 audio at 192Kbps - about 30% better compression. CD-quality sound in AAC requires somewhere between 96Kbps and 128Kbps. AAC is also one part of the MPEG-4 specification, as one of several audio compressors an MPEG-4 stream may use depending on bandwidth and quality requirements.

(This presumes the self-reference is excused by providing our material that's not available on the Web in other forms)

People still question whether iTunes' default encoding is as good as you can get; QuickTime's own encoding dialog boxes provide higher-quality options for AAC than iTunes does, but the encoding takes longer. Still, files you create yourself are in the standard MPEG-4 format that itself is based on the QuickTime file format, and should play on any device that's MPEG-4 compatible. I've heard that on some Windows machines, you have to rename them to end in ".mp4" instead of ".m4a" to get them recognized, but once you do, it works fine.

At the moment, the iPod is the only portable player that I know of that supports MPEG-4 audio, but others could easily do so by paying licensing fees. That wouldn't give them access to Apple's protected format, but since you can burn those to CD and re-import in any format you want, it's more of an inconvenience than a show-stopper, IMHO.
posted by mdeatherage at 9:44 AM on February 4, 2004

I've got pretty amazing ears (imo) and I *really* like the sound of 192kbs AAC files. I've A-B'd them with 256kbs lame-encoded mp3 files and I can hear the difference on any recording that has a lot of well-recorded cymbals or a well-engineered treble 'sheen' on it. The new stereolab album has a lot of sweetness in the higher frequencies and I have an iTMS AAC version and a CD and a 256kbs lame-encoded version.

I can barely tell the difference between the CD and the AAC file... they are different but I can't tell which is which... but the mp3 sounds flat. Honest.

Oh yeah, don't convert from AAC to mp3 or vice versa. It will really kill your tracks.
posted by n9 at 2:49 PM on February 4, 2004

But wait... if anyone is still here... are the AACs that I rip in iTunes infinitely portable? As in can I play them at work and give theoretical CD-Rs of them to my friends? I know that the ACCs that the iTunes store sells are not portable in this way. There's DMRC portability stoppage built in. Can someone give a link that declares definitively that iTunes-made AACs don't have DMCA?
posted by squirrel at 10:51 PM on February 8, 2004

I have iTunes and I can tell you, tracks you rip yourself don't have DRM of any kind.
posted by kindall at 4:12 PM on February 27, 2004