AAC to MP3 for fair use?

September 2, 2004 7:16 AM

I've been buying my wife tracks from iTunes and putting them on her Archos Jukebox. Since the Archos doesn't accept the aac format, I have to burn them from Archos onto CDs and then rip the CDs back into my PC and then download the ripped files onto her Jukebox. (I don't feel like I'm cheating Apple out of revenue, because only my wife listens to this music.) [More Inside.]

According to my research, this is the only way to move music from iTunes Music Store to a non-aac device. But I'd LOVE to find a method that is less complicated and also cuts analog out of the process.

So here's what I'm wondering: There are all sorts of virtual CD programs out there -- you know, the kind of app that fools your PC into thinking part of your hard drive is a CD in a CD drive. But the only way I've ever seen these virtual drives work is with an image of an actual CD. Why should this be the case? Why shouldn't you be about to create a virtual CD image (a virtual virtual)? In other words, why can't you create a file that never came from an actual CD but which your computer THINKS came from a CD? It's all 1s and 0s, right?

If I could do this, I could burn a fake CD from iTunes and then fool the Archos into downloading MP3s from that fake CD.

Does this app not exist because no one has bothered to create it? Is there a technical issue that makes it impossible? Or does it exist and I just don't know about it?

posted by grumblebee to computers & internet (35 comments total)

Why can't you just use iTunes to convert the tunes to MP3? If you want to retain the AAC versions, just move them out of their folder somewhere else temporarily until you get the MP3s onto the Archos. Got to be easier than what you're doing, or contemplating doing.
posted by luser at 7:27 AM on September 2, 2004

Unless maybe you can't do that with Store-bought tracks. I don't know, I only ever do it with tracks I've ripped myself.
posted by luser at 7:28 AM on September 2, 2004

Or you could get your tunes elsewhere. All this converting is killing your audio quality.
posted by mookieproof at 7:30 AM on September 2, 2004

What you're doing doesn't include any analog steps, so the audio quality's as good as if you did a direct conversion, assuming your CD-ROM drive can rip CDs accurately. A "direct" conversion is possible. There are various programs that can un-protect the .m4p programs; the best one is called hymn, formerly PlayFair (I'm not linking to it due to its quasi/barely/not legal status... you can find it on Google). You can then convert the unencumbered mp4/aac file to MP3 directly with dBpowerAMP, which uses the high-quality LAME MP3 encoder. But, yeah, mookieproof has a point: by doing this you're making the songs sound worse. But, if your wife thinks they sound fine, go for it. This sort of thing should definitely fall under Fair Use.
posted by zsazsa at 7:32 AM on September 2, 2004

I'd listen to the other ideas first, but if you want to continue down this path...

Your CD burning software should offer a method for creating an ISO image file. On Roxio's Easy CD Creater once files are ready to be burnt I can go to File/Create CD Hard Disk Image and that'll do it.

From there you'll need to mount that ISO image as a virtual CD, which is close to the term I just googled that turned up this page and says:

Mounting ISO files virtually
The following tool for Windows XP allows image files to be mounted virtually as CD-ROM devices. This tool is provided here for your convenience, and is unsupported by Microsoft Product Support Services.

Virtual CD-ROM Control Panel for Windows XP

Only works in Windows XP though. What OS do you have?
posted by jwells at 7:35 AM on September 2, 2004

I'm almost positive that you can't convert from aac to mp3 in iTunes. And I don't think anyone else has come up with an aac to mp3 converter (if they did, my problems would be solved.)

As for getting the songs elsewhere, I doubt there are any online music stores that sell in pure mp3 format (the only format the Jukebox accpets). This would make piracy too easy. So my options are illegal download (which I'd rather not do) and actually buying CDs (which would be a waste when my wife only wants one track).

Eventually, I'll probably just break down and get her an iPod. But even so, I'm interested in the virtual virtual CD thing, anway because ... well, just because I'm interested.

[On Preview, jwells info seems on target. For those of you who are suggesting getting the tracks elsewhere, what do you mean? Am I wrong about mp3s? Is there a music store that actually sells normal, unprotected mp3s? I can't imagine this...

Oh, yeah, I'm using OSX.]
posted by grumblebee at 7:39 AM on September 2, 2004

zsazsa, would this process really make the songs sound worse than any other mp3s she has? I assume -- since the whole process is digital -- that the quality reduction is due to the fact that mp3s are intrinsically worse than m4ps. But her Jukebox can only play mp3s, so that's that quality she always hears.
posted by grumblebee at 7:44 AM on September 2, 2004

Jesus, I must have just had a brain fart. I'm NOT using OSX. I don't even own a Mac. I'm using WinXP. (Apple, get out of my HEEEEEAD!!!!)
posted by grumblebee at 7:45 AM on September 2, 2004

grumblebee -- AAC and MP3 both compress songs by discarding bits that you normally wouldn't hear. They're both lossy compression schemes. The thing is they throw away different bits, so when you compress a file and then recompress a file, you're throwing away more bits than when you just compress it once. Even going from MP3 to MP3 will introduce additional noise into the song.

You probably won't hear the difference. If you're wife's not complaining, then it's not something to worry about, but I try not to re-encode lossy formats any more than I need to.
posted by willnot at 7:57 AM on September 2, 2004

Darnit... I was just about to tell you that you were golden. It sounds like OSX can read ISO files directly. But nooooo.... :-)

I ran into one hiccup with what I posted above. With the data format set to CD I couldn't save as an ISO image file. CIF was the only option. I really haven't done much CD burning so I've no idea of what a CIF file is, or if it can be converted to ISO, etc..
posted by jwells at 8:00 AM on September 2, 2004

oops, I meant "data format set to audio".
posted by jwells at 8:02 AM on September 2, 2004

Even going from MP3 to MP3 will introduce additional noise into the song.

I'm sure you're right, but I find this odd. If you resave a jpeg (as long as you save at 100% quality), there's no new loss (or am I wrong?)

Why should the mp3 format be different? Is this just a matter of mp3-creation-software not being smart enough? Couldn't someone write an app that looks at an mp3, sees that it's already compressed, and so not add any addirtional compression?
posted by grumblebee at 8:04 AM on September 2, 2004

Audio Hijack might let you cut the cd burning part out of the process.
posted by ph00dz at 8:11 AM on September 2, 2004

Engadget posted How to play purchased music on other systems… which doesn't use CD-Rs. Basically, you use Hymm to remove the DRM from your purchased music. People above are claiming that non-protected AAC files can be converted to MP3s in iTunes and I have no reason to doubt them.

And the people who say you'll lose quality are right, unless the iTMS starts sending songs encoded in Apple Lossless Codec.

PoliticalRant: The DRM on the AAC is there specifically to entice you to buy an iPod. The fact that you can't play them easily on a non-iPod means the system is working perfectly. Think about that when you're buying your music from the iTMS.
posted by revgeorge at 8:12 AM on September 2, 2004

You could try getting your music from Emusic.com instead.

They sell MP3s.
posted by jaded at 8:26 AM on September 2, 2004

Jesus, I must have just had a brain fart. I'm NOT using OSX. I don't even own a Mac.

You made my day, gb.
posted by anathema at 8:28 AM on September 2, 2004

Going from AAC to MP3 is lossy, but all compressed music tends to sound bad, the players tend to have cheesy D to A chips, and the headphones tend to be cheesy. I mean, we're splitting hairs here. I have some AAC to MP3 stuff that sounds fine, sure its lost some luster, but its no big deal. Its not like old school tape copies or anything. Heck, I'd be surprised if most people could tell the difference and if they did if they would even care.
posted by skallas at 8:29 AM on September 2, 2004

If you resave a jpeg (as long as you save at 100% quality), there's no new loss (or am I wrong?)

I'm 99% sure you are: I think you lose a little bit more information every time you open and resave a JPEG, even at 100% quality. That's why it's always better to save a source version in a lossless format and make future edits to it. The same principle applies to any lossy compression scheme.
posted by timeistight at 8:33 AM on September 2, 2004

Speaking of iTunes and other music stores...anyone have advice for Napster that is telling me that it can't establish a connection during login? Worked a few days ago but for the past 4 all it does is time out when I try to login.

I've uninstalled, re-installed twice. WinXP.
posted by karmaville at 8:37 AM on September 2, 2004

>If you resave a jpeg (as long as you save at 100% quality), there's no new loss (or am I wrong?)

Not really. Lets say you open a jpeg in a photo editor. The editor converts it to a bitmap. Now you are free to edit it as your wish. When you are done it takes that bitmap and encodes it to whatever you like (jpeg, gif, skallasformat, whatever) and will add further compression artifacts. Even a 10 value jpeg still uses noticable compression I believe.
posted by skallas at 8:37 AM on September 2, 2004

Or imagine opening a JPEG, resizing it, then resizing the resize, then resizing that resize, etc. Yes, it may take many iterations to lose significant quality, but you're better off taking fewer steps.
posted by mookieproof at 8:41 AM on September 2, 2004

<self-link, derail>A while ago, to "prove" that multi-generational MP3 encoding can wreck the quality of a song, I re-encoded a song 100 times, encoding with both a worst-case (bladeenc) and best-case (LAME) MP3 encoder. Sorry, I don't have the original, but the quality loss is pretty obvious without one, even in the 10th generation.
Bladeenc: 10 generations / 50 generations / 100 generations. LAME: 100 generations.</self-link, derail>

Back on topic, ISO images are data-only: they can't store CD audio. Some proprietary CD image formats like Nero's .nrg can store audio. But, seriously, the easiest and most direct way is to use hymn to un-DRM the iTMS songs and convert the unprotected files to mp3 with either iTunes or dBpowerAMP.
posted by zsazsa at 8:48 AM on September 2, 2004

skallas, your claim about jpegs interested me, so I just conducted a couple of tests similar to zsazsa's, but with images not sounds.

First, I creaded a PSD, saved it as a 100% quality jpeg, and then opened that jpeg and save-as'ed it as another 100$ quality jpeg. I did this 10 times. Then I compared the 10th generation with the 1st generation (the 1st jpeg, not the psd). They were identical. I judged this (1) by eye-balling, (2) by looking at histograms of both files and (3) by sampling colors at random.

I then tried the test again, this time by saving the original psd as a jpeg at 0% quality, which naturally looked terrible. I then made a copy of the bad jpeg at 100% quality and made a copy of the copy, also at 100% quality. I went on this way, again, for 10 generations. Again, no difference between generation 1 and generation 10.

Of course, I know that if I had kept saving at a lower generation than 100%, I WOULD have introduced new compression artifacts. But I think I've proved to myself that re-compressing a jpeg at 100% (in Photoshop's Save for Web window) doesn't add any further compression.
posted by grumblebee at 9:01 AM on September 2, 2004

I hear you, zsazsa, and I know I'm moving way far away from practicality here ... but I don't see why, in theory, one couldn't fool a PC into believing that info from the hard drive wasn't info from ANY other sort of divice or disk. It's all binary, right? If I wanted to (for some odd reason), I should be able to tell my computer that info coming from the hard drive is actually info coming from a joystick.
posted by grumblebee at 9:05 AM on September 2, 2004

grumblebee, I will bet that whatever program you're using is keeping an internal copy of the jpeg and since you've made no changes to the image just making an identical copy of the original file. Try this:

1. Open your image, save it as a lossless PNG file (or TIFF or other lossless format)
   
2. Close all your images
   
3. Open the PNG
   
4. Save it as a JPEG with a new filename
   
5. Close all your images
   
6. Open the JPEG image
   
7. Save it as a PNG with a new filename
   
8. Close all your images
   
9. Go to step 3
   

posted by substrate at 9:26 AM on September 2, 2004

grumblebee: Of course you can fool the computer into thinking data from anywhere is coming from somewhere else, but I hope you like writing low-level drivers for the kernel.
posted by thebabelfish at 9:34 AM on September 2, 2004

Shame you didn't have a mac, grumblebee (unless you can get iMovie for Windows).
posted by Blue Stone at 9:44 AM on September 2, 2004

substrate, this is a bit different. YEs, when translating to jpeg from another format (i.e. PNG) there WILL be a loss. There was definitely a loss when I went from the psd to the 100% quality jpeg. I'm literally talking about goring from jpeg to jpeg. When I get some time, I'll test this again by resaving a jpeg over and over, switching between two different applications -- say Photoshop and Paint Show Pro.

I'm not sure this will yield a definitive answer, though, because those two apps might use different algorithms to decide what to keep and what to throw out.
posted by grumblebee at 10:53 AM on September 2, 2004

The way I understand it, JPG compresses an image by by describing groups of pixels as opposed to the individual pixels of a bit-map. If there is large area of the same color (as there usually are in pictures) jpg only has to describe the shape size and color of it, instead of repeating what is basically redundant information.
I assume that the quality defines the tolerance: the lower the quality the more similar (but different) colors will be rendered the same.In theory multiple generations, compressed at the same rate will not experience any further loss.
I also wanted to play so I compressed the same image 10 times at 70% quality each time (albeit with the same application) and the file remained the same size, proving in my opinion that there was no further compression. They also looked the same to my untrained eye.
posted by golo at 11:11 AM on September 2, 2004

golo - I'm not CoDec expert, but what you describe sounds more like GIF than JPEG to me. I can't vouch for the accuracy, but this sounds like a reasonable explanation of how JPEG compression works.
posted by willnot at 11:51 AM on September 2, 2004

I hate to continue this thread derail, but I'd like to corroborate the JPEG-resaving posts, but with a couple caveats. Given the absensce of rounding errors and a good JPEG implementation, a JPEG image resaved over and over again at the exact same quality level should be if not very close exactly the same to the original JPEG image. If you change the quality between saves or make changes to the content of an image, all bets are off.

Following the same model as my mp3 experiments, I compressed the famous Lena image 1000 times over using Imagemagick's command line tool "convert." While the files differed in an exact binary comparison, the actual loss of image quality was either nil or imperceptible. Note that at quality=100, no quantization is done so no data is intentionally thrown out, making it extremely close to the original.

quality=100: Original - 100 generations - 1000 generations
quality=40: Original - 100 generations - 1000 generations

Once we vary the quality level, you will lose quality in multigenerational copies. I ran through 1000 compressions with a random quality variance of 20.
50 < quality < 70: Original - 10 generations - 100 generations - 1000 generations
80 < quality < 100: Original - 10 generations - 100 generations - 1000 generations

At the 1000 generation mark of the 50-70 set, we can really see the cute little 8x8 pixel blocks that JPEG works at. I hope this goes to clear some things out about JPEG recompression. If you keep the image exactly the same and re-save at the same quality level, you won't lose much if at all. But, why would you do that? Maybe if you wanted to crop an image exactly along those 8x8 blocks, or maybe if you just wanted to add text to a small portion of the image. Do any drastic changes, like resize the whole image, or change the quality level, and you will lose quality over successive recompressions. It'd be interesting to do some tests with constant quality level and changing things in the image like color levels, brightness, contrast, etc. Imagemagick can do it, but I think I've wasted enough time today on this.

Anyhoo, grumblebee, I hope we fixed your iTunes problem. :)
posted by zsazsa at 12:44 PM on September 2, 2004

Yeah, I think I have good enough info to solve the iTunes problem as much as it can be solved.

I don't know if the originator of a thread has the right to bless a derailment, but if so, I bless this one. The jpeg info is very interesting to me. Thanks for the experiments, zsazsa.
posted by grumblebee at 12:51 PM on September 2, 2004

By the way, your final two lowest quaility examples are really cool looking. I've never seen quite that look before, even using pixilate and noise effects.
posted by grumblebee at 12:54 PM on September 2, 2004

in a bizarre twist of something or other, your burning then ripping is exactly exactly what microsoft recommends for people who wish to use their music service with their Ipods.
posted by crush-onastick at 1:50 PM on September 2, 2004

Not sure if you got a definite answer, but using the Hymn to unprotected AAC to "Convert to MP3" in iTunes method does work without a hitch. Just make sure that in your Preferences you have your Importing settings how you want them (its AAC by default instead of MP3).

Also, I'm not sure why they didn't mention it in the Engadget How-To, but you don't have to use the command line with Hymn on Windows. No GUI yet, but just select your protected AAC files (multiple files at once, even), and drag them onto the Hymn executable. It will run the processes and you'll end up with unprotected copies in the same folder as the original files. Tada!
posted by shinynewnick at 7:41 PM on September 2, 2004