AAC Put To The Test

technology is sexy writes "Following the increasing popularity of AAC in online music stores and the growing amount of implementations in software and hardware, the format is now being put to the test. How well does Apple's implementation fare against Ahead Nero, Sorenson or the Open Source FAAC at the popular bitrate of 128kbps? Find out for yourself and help by submitting the results. You can find instructions on how to participate here. The best AAC codec gets to face MP3, MP3Pro, Vorbis, MusePack and WMA in the next test. Previous test results at 64kbps can be found here."

Comments

crap in, crap out

[larry bagina]

just remember, every codec depends on the quality of what it is encoding. I haven't heard any AAC encoded music myself (i use uncompressed wav or 256khz mp3 myself), but Apple allegedly uses the master recordings to encode their files.

Most mp3s or oggs you find out there are from someone's CD-Rom drive, who knows how the disc looked, or how much jitter there was. I have heard stories of people downloading songs to find a skip or two in the middle, or been an amalgam of two different files accidently spliced together.

I'd hazard a guess that most people that encode with ogg-vorbis do a better ripping and encoding job, though.

Re:crap in, crap out

[nattt]

Master recording? They'll use the CD like everyone else.

Jitter? You don't know what you're talking about. Jitter is a phenonema that occurs ONLY in the D to A converter. If you load a program from CD, do you get the wrong bytes because of jitter? If you're going to use an audiophool buzzword, at least understand what it's about beforehand.

Re:crap in, crap out

[73939133]

I haven't heard any AAC encoded music myself (i use uncompressed wav or 256khz mp3 myself), but Apple allegedly uses the master recordings to encode their files.

Unless you are psychic, you won't be able to tell the difference between an MP3 ripped from a "master recording" (whatever that may be) and an MP3 ripped from a CD. And unless you are an alien, a dog, or an infant, you are lucky to hear anything meaninful above 16khz, which means that 44khz sampling is plenty.

Most mp3s or oggs you find out there are from someone's CD-Rom drive, who knows how the disc looked, or how much jitter there was.

Yeah, those MP3s are even worse when people forget to clean and replace the stylus in their CD-ROM drive regularly. Those CD-ROM diamond styluses sure wear down fast. I expect you clean yours regularly, right?

Re:crap in, crap out

[evilviper]

I have heard stories of people downloading songs to find a skip or two in the middle, or been an amalgam of two different files accidently spliced together.

These artifacts are almost always the result of early P2P networks, that would download a missing piece of a file from anything that had the same name... Of course you can find these now, because even with the improvements, people often keep their old files.

I will admit that some pops were the results of bad audio rippers, but that was in the infancy of CD ripping. These days, the most basic software can produce a perfect rip 100% of the time, and has great default settings for encoding. The only thing a luser could do to screw things up is to change the quality settings (which few bother with) or screw things up if they transfer the file.

Face it, the problems with audio quality was the software, and it's simply that the old files were still around in force until recently. Now, even the biggest idiots can encode perfect quality files, and can transfer them over P2P networks properly.

An honest question - who cares?

[LeoDV]

This might get modded Troll, but it's an honest question. Whenever I rip a CD, I encode it into mathematically loseless MP3s, and with the cheapness of disk space these days, I can't stop being amazed at how many people don't do the same. If the quality can be compressed into something loseless from the original digital medium (the CD), then who cares if AAC sounds better than OGG sounds better than WMA sounds better than MP3 at 64 kb/s?

Please enlighten me, I'm actually, honestly, curious.

Re:An honest question - who cares?

[Alric]

I'm not sure what the original post meant, but from my days working in the psych labs, "triple blind" is a colloquial term for when the two parties are not aware of the test or the true nature of the test.

For example, I am the researcher, and you are the subject. I am giving you the Pepsi challenge. I do not know which container has Pepsi, and which one was Coke. I administer the test. However, Xavier, the research director has been slowly increasing the temperature in the room to observe if this affects your and my interpersonal communication.

1. You are ignorant of the test data.
2. I am ignorant of the test dat.
3. We are both ignorant of the true test.

MPEG2-AAC not too bad

[kungfoolouie]

I happen to own a Panasonic SV-AV30 (4-in-1), and music management app that comes with it has to options to save in MP3 or MPEG2-AAC. Lately, I have been transcoding the audio from mp3s and cd to 96kbps AAC and the results are surprisingly good. I play it in my car and have not really noticed a much of a difference.

Obviously, the tracks which were bad to begin with will be bad as AACs.

BTW, I have been playing/making music for 14 years and have a pretty good ear when it comes to tone and timbre. Hi-hats on CDs have always bothered me with the lack of warmth and fullness of timbre. So take my word for it if I saw it's not too bad :-)

Sigh. Not a way to get good results

[Anonymous Coward]

Please note that the survey's host makes no claims that what he's doing is in any way scientific. Keep that in mind. The reasons why the results are to be taken with a grain of salt:

1. There is no guarantee of clean data - the users are expected to generate their own files. MIstakes happen.
2. The type of user who participates in this (and more likely in the OGG vs AAC coming debate) may have some predisposed bias. There is no way to weed out any placebo effects.
3. There is no way to weed out folks who have tin ears. I don't want some idiot who loves dance forming an opinion about Bach not sounding "boomy" enough

This may fly in the face of the /. crowd, but an open call to the masses to submit their opinions is not science nor does it have any scientific meaning.

Not a good test of iTunes service

[benwaggoner]

It looks like they're working with 16-bit source, not the 24-bit source that most of the iTunes AAC files are ripped from. So this test, while certainly very interesting, won't be useful to determine the iTunes music store quality.

Re:I prefer analog

[afidel]

What you prefer the loss of the pits on your LP wearing as the needle passes through the grooves? Yeah spectral analysis shows that after three plays with a high end player the LP has already lost MORE dynamic range then a ADAT recording, and of course in hundreds of plays and a couple generations the digital copy is obviously superior, plus getting vinyl from mail order sucks, I know I DJ and the % of DOA stuff is way too high for my liking (especially if it's a white label or rare import, ususally means I get the insurance $ but never find the music again for a reasonable price). Analog has its place (like scratching, cd's just are not the same) but long term quality is not where it's at.

I care.

[crapulent]

I care because I have not fallen for the "golden ears" fallacy. To me, 192kbps ABR lame-encoded sounds exactly like the original. I don't have super expensive speakers attached to the computer, nor do I have a fancy sound card (Creative Live 5.1.) Storing music losslessly is a waste of space to me. Sometimes I like to share music files and it's a heck of a lot easier and others are a heck of a lot more interested in trading compressed music compared to lossless files. And I can put a heck of a lot more of them on a CDR. And should I wish to listem to them in my MP3 player with limited memory, I'm sure as hell not going to use a lossless format.

If YOU want to use up your hard drive space, internet bandwidth, and blank media with huge lossless encoded files, feel free. But don't get all smug and proclaim to not have any idea why anyone would not want to waste their resources.

Oh, and I'm not going to touch that "mathematically lossless" crap, others have covered that already.

Re:I care.

[Admiral Burrito]

I care because I have not fallen for the "golden ears" fallacy. To me, 192kbps ABR lame-encoded sounds exactly like the original. I don't have super expensive speakers attached to the computer, nor do I have a fancy sound card (Creative Live 5.1.) Storing music losslessly is a waste of space to me.

The only problem is, if MP3 or AAC or whatever lossy format fall out of fashion (due to patent or whatever), you could end up with a bunch of files you can't play on the latest gadgets and software. Then you need to re-encode them in whatever the new format, which will add additional lossiness due to the transcoding (unless you re-rip everything, which is a major pain).

If you use a lossless algorithm, you can re-encode to whatever you like. For example, it wouldn't be terribly difficult to take a losslessly-encoded file, decompress it, and run it through a fast MP3 encoder as part of the process of copying the file to your portable. Then if ACC or OGG or whatever displace MP3, you can just change the script when you upgrade your portable.

I agree about the "golden ear" fallacy. Some people avoid lossy because they want "perfect" sound. But there is no "perfect", really... the original recording required sound travelling through air, which is lossy. The recording equipment was also lossy, as is your playback equipment. Your ears and mind are also lossy. Very lossy, in fact... Your ears being lossy is why these lossy audio codecs work as well as they do (they "lose" the parts that your ears/mind would lose anyway).

Re-encoding

[cmason]

For what should be fairly obvious reasons, I'd rather see a comparison of encoders re-encoding AAC to MP3. I tried this several weeks ago using AudioHijack and the iTunes MP3 encoder, and the results were less than stellar.

I imagine that an encoder could be optimized for re-encoding. I wonder if anyone is working on this. I'd like to write a program which would automatically do this conversion in my music library, but currently I can't stand the loss of quality.

Re:Re-encoding

[cmason]

This is obviously true. However, the reason I want to do this is to play iTunes Music Store purchased music on non-Apple hardware. I have no source material to rip from other than the AAC track I download.

I think LAME actually does a pretty good job of re-encoding AAC to MP3. At least, I can't tell the difference (unlike when using iTunes to re-encode, where I most definitely could). This is good enough for me.

-c

Re:I prefer analog

[Achoi77]

You could always get a laser turntable if you don't want to scratch your record. Expensive, though.

not likely to make a difference

[Trepidity]

The quality loss in dithering 24->16 is much less than the quality loss in doing a lossy encode to 128kbps AAC, by at least an order of magnitude.

Re:Thank iTunes for the skips etc.

[lvdrproject]

Er? I'm not an "audiophile" or anything, but as far as i knew VBR is the best quality-for-size ratio you can get with MP3. I don't understand "cracking and whooshing". Can you explain? :/

AAC 5.1 surround sound work great in matroska

[ChristianHJW]

You question the use of AAC audio ? why bother, if we have MP3 for music ? Well, as a quality freak i will only use musepack ( MPC ) for audio compression, if ever, but for DVD backups with the DivX or XviD codec, i am using AAC as standard now. Why ? well, the new Nero encoder will allow you to create high quality, true 5.1 surround AAC audio with a bitrate of about 180 - 240 kbps, from 5.1 AIFF or WAV files. Use the matroska container and DirectShow parser filter ( http://www.matroska.org ) to store your DivX video with AAC 5.1 and the CoreAAC DirectShow decoder filter to playback on Windows. A sample file ( 10 MB ) in incredible video quality, plus some documentation how to play and make such files, can be found here : http://corecodec.com/modules.php?op=modload&name=P NphpBB2&file=viewtopic&t=328

Re:Oh Brother...

[2nd Post!]

The only reason Apple is using AAC is because it is an obscure format which tends to lock users into a Mac/iPod solution.

No, the only reason Apple is using AAC is because it's an open, documented, non vendor-locked format that cannot be simply hijacked and manipulated by, say, Microsoft.

AAC is cross platform; in fact, AAC is the logical successor to MP3, so everything you love or hate about MP3, ideologically, should apply to AAC. To think otherwise seems silly and ignorant to me.