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Hydrogenaudio AAC Listening Test Results
caffeine_monkey writes "Hydrogenaudio's AAC public listening test, previously posted on Slashdot, is now over and the results are in. The test compared five codecs at 128 kbps, including Psytel, Nero, Sorenson Squeeze, QuickTime, and FAAC. The winner? 'QuickTime is a clear winner, performing much better than the competition. Sorenson Squeeze, Psytel AACenc and Nero are tied, with Sorenson slightly higher than the others. Faac is clearly the worst.'"
woohoo
I knew that subject would get your respective attentions, but... the obvious question is, why wasn't WMA v8/v9 included in the test?
- Oisin
PGP KeyId: 0x08D63965
003 dnf8 oao
whoops
ZING
AAC is copy protected. Only use this if you want Apple to control all of your music. You should look at free formats like ZIP or JPG
...Ogg blah blah blah blah...
I have the Ultimate Guide
I'm not Seth.
Any particular reason they didnt include WMA? Its pretty widely known that WMA offers superior quality (and better compression). I guess they were just scared to confirm this fact.
While it may be relevant to have a comparison between different AAC encoders the trial would have much more relevance to real life if it had included ogg and mp3.
A little extra work for a lot more sense in the results.
Have fun
Xander
Slashdot Beta should die a painful death.
QuickTime won? Surely some mistake, QuickTime is a container format. It can't possibly win an audio codec listening competition, as it's not a codec. If the /. story is transcribed correctly, then that already trashes the credibility of this story.
Do not confuse FAAC and FLAC (the lossless audio format from Xiph).
Btw, why does this test compare only proprietary formats and not free (as speech) formats like Ogg Vorbis or FLAC ?
The following are actual quotes I've read from audiophiles on the net. Enjoy.
"Pulling harmonics together from a jumbled auditory stream to form a coherent harmonic envelope."
"Image outlines were sharply focused in space with believable palpability."
"There was plenty of bass detail to behold."
"The music flows with gusto and verve. It squeezes instrumental images into incredibly palpable outlines."
"...more muscle and definition, and a heart that is pure gold."
"Most preamps when pushed hard change their sonic signature."
"Harmonic colors were somewhat on the dark side."
"By using the $450 gold plated RCA stereo jumper cables for all line-level connections, and the newly available $1200 gold plated XYZ speaker wires, we were able to achieve a distinct improvement in highs and the deepest rich bass lows I have ever heard. A massive improvement over ordinary old copper."
"These cables deliver big time! The sound is surprsingly smooth and spacious, with particularly sweet upper octaves."
"If you connect a ground to the chassis of your power amplifer and use 4 gauge wire connected to a bucket of salt water with a copper coil in it, your mids and highs will be the sweetest you have ever heard. Works with car audio systems too. Place the bucket in the trunk and reduce speed on corners and when braking, to avoid spillage."
"Special wooden resonator disks made in Asia from a special tree, only found in one area. Placing these under EACH of your components, at strategic locations will remove 'unwanted resonances', and DRAMATIC improval tonal quality. The difference is astounding. These disks of wood sell for around $100 to $400 EACH (depending on size)." (See the top of this web page!)
"somewhat fuzzy portrayal of image outlines."
"Harmonic textures ebbed and flowed with startling dynamic nuances and the sort of liquidity and purity one only comes to associate with world-class audio products."
"Harmonic textures are painted slightly gray in color."
"Spatial detail was painted with a fine brush that readily resolved massed voices and the air around individual instruments."
"Image outlines, however, are more precisely focused within the soundstage and in general the Accordance is capable of sketching out a convincing 3-D acoustic impression."
"It felt like I had crawled into a warm and inviting sonic womb."
"Not content with straight S.E.X. (the single-ended experimenter's kit), the Doctor introduces the "69" tapered pipe loudspeaker. Sounds like a recipe for a mind-blowing sonic orgasm."
"The impression of speed and control was strong."
"Bass lines were fleshed out with excellent definition."
"It is less lush sounding than..."
"...force feeding the listener an earful of detail; more accurately, a barrage of in-your-face zingers that becomes almost an instant irritant."
"Each tube brand seems to have a unique flavor of its own."
"Certain busy passages of music get congested."
"... sounds either euphonic or bright."
"The Equilibre ($8,475) - nominally a 60-watt stereo amp."
"It could well explain the sweet sounds that come from using passive preamps straight into the power amplifiers."
"...with an easy-to-drive impedance magnitude."
"Rendition of harmonic colors was suave and smooth, with a believable sugar coating."
"Exposure of low-level detail, even in complex passages, without leaving anything to the imagination."
"The mids are vivid in spades with wave after wave of honey-coated harmonic bliss."
"The midbass region is "fun"
"the upper mids are a bit more laid back than I would like."
"the low bottom end is not there..."
I'm not Seth.
Though they ARE Apple and tend to exaggerate claims (rivals CD quality? Pssh... Ogg Vorbis can do better than AAC)
You are possibly the most stupid person in the entire universe.
For once, shut the fuck up about ogg please. It's an article about 4 different codecs on the same format.
DIE.
Would I be correct in assuming that it is the QuickTime codec that is used in iTunes? I can't imagine Apple would go to the trouble of writing two different codecs.
"Reality is merely an illusion, albeit a very persistent one " -Albert Einstein
Comparing high quality compressed audio. Hrm...so when is the RIAA going to hand these guys a C&D or a lawsuit?
Let's get one thing perfectly clear, I did not vote for George W Bush, and I do not endorse what he does or says.
"
That's right folks. There's the dark secret about your new darling audio format, and your favorite operating system. For as long as Apple controls the codecs, AAC will never come to Linux. I cannot emphasize enough how much of a fallacy it is to be lulled by the promises of commercial software. If this is not enough of a smack in the ass for you, I don't know what is.
They compared a constant bit rate encoding at one bit rate, and didn't compare it against mp3, mp3pro, ogg or wma?
Could they have found a way to make this test less interesting or useful? Who's the target audience here? The encoder developers? I'd have thought that they'd be doing their own tests.
Let's at least liven it up a bit. Guesses on the dupe story? I'm thinking seven hours, and Taco.
If you were blocking sigs, you wouldn't have to read this.
its being played inside of a tin can?
What I'm curious about is, there was some discussion before about the differences between the original AAC encoder that came with QT, and the newer one that now ships with QT 6.3 (and ties to iTunes). The original encoder was said to have sucked. This one, if I'm reading this right, is now very good...?
Anyways, I must have lead ears. I used to rip my MP3s at 160kbps, now I do 160kbit AACs, and cannot really tell the difference. AAC seems a tiny bit better maybe but could be a placebo effect.
If Jesus wants me it knows where to find me.
From Apple's AAC page
Because of its exceptional performance and quality, Advanced Audio Coding (AAC) is at the core of the MPEG-4 and 3GPP specifications and is the new audio codec of choice for Internet, wireless, and digital broadcast arenas. AAC provides audio encoding that compresses much more efficiently than older formats such as MP3, yet delivers quality rivaling that of uncompressed CD audio.
AAC was developed by the MPEG group that includes Dolby, Fraunhofer (FhG), AT&T, Sony, and Nokia--companies that have also been involved in the development of audio codecs such as MP3 and AC3 (also known as Dolby Digital). The AAC codec in QuickTime 6 builds upon new, state-of-the art signal processing technology from Dolby Laboratories and brings true variable bit rate (VBR) audio encoding to QuickTime.
From Via Licensing
MPEG-4 AAC has been specified as the high-quality general audio coder for 3G wireless terminals. Apple Computer has incorporated MPEG-4 AAC into QuickTime 6 and iTunes 4, as well as the latest version of its award-winning iPod portable music player. The Digital Radio Mondiale system (the next-generation digital replacement for radio broadcasting under 30 MHZ) builds on the audio coding of MPEG-4 AAC. These exciting platforms represent the state of the art in audio coding--and Via Licensing is pleased to offer the MPEG-4 AAC Patent License Agreement.
The MPEG-4 AAC standard incorporates MPEG-2 AAC, forming the basis of the MPEG-4 audio compression technology for data rates above 32 kbps per channel. Additional tools increase the effectiveness of MPEG-2 AAC at lower bit rates, and add scalability or error resilience characteristics. These additional tools extend AAC into its MPEG-4 incarnation (ISO/IEC 14496-3, Subpart 4).
A copy of the MPEG-4 Audio standard can be purchased from the ISO online store (search for "14496-3").
Makes me wonder why they didn't include Windows Media and Real Media codecs in the test.....
-- Sig
MIT and Boston College Fight RIAA
Somewhat offtopic, but what the heck.. Hydrogenaudio is using thttpd! Long live thttpd!
http://home.cfl.rr.com/happysurfer/audio_bs.htm
someone else on this has linked it. Please always include the link for our entertainment.
Its so fucking true! Everytime an audio format gets mentioned all the simpering open sores twats come out squealing 'what about OGG? pleeeeeeeeeeeeeeaaaaaaasee mummy pleeasssee dont ignore me'
SHUT THE FUCK UP ABOUT OGG YOU PASTY FACED FAT HIPPY CUNTS
" Its pretty widely known that WMA offers superior quality"
Actually, the tests that show this were at the 64kbs range which is not useful except for voice. The break-even point is 128, and above that sampling rate, virtually everything (including MP3) is superior to WMA.
So I guess if you want a good voice-streaming codec, WMA is your codec. But for music, it isn't very good.
But perhaps you're a person who primarily listens to books on tape or something like that?
You are possibly the most stupid person in the entire universe.
After the fucking squares who moderated you...
Actually by default records it inside a virtual tin-can. Without that, the RIAA would never have agreed to the iTunes software.
WAY back in the day Ken Thompson was interviewed for Wired and he played music on his computer using a lossy compression called PAC which he had coded in C from Fortran with the original developers. This was WAY before MP3.
Just a short time back, it seems, he claimed it was still way better than MP3.
How come it wasn't in this contest and in fact I cannot find anything more about it anywhere??
It's Christmas everyday with BitTorrent.
in my opining they all faacing suck
I didn't know his middle name started with a 'A'
I thought the minimum number of runs for statistical confidence in a test is more like 50, not between 11 and 18. I find it surprising that it should be that low, seeing that the call for subjects was posted on /.
Interesting results though.
"When a ball dreams, it dreams it's a frisbee"
Uhm, has anyone considered that this might refer to the AAC codec that comes with Quicktime? On the Mac platform QuickTime is the native audio/video solution, much like the Windows codec mechanism. QuickTime as a platform ships with bunches of codecs, among which an AAC one.
:)
The interesting thing here is that I've been told that the codec that iTunes uses for AAC encoding isn't very good and that Apple used a third-party codec to encode their iTunes Music Store tracks. Oh well, so much for unsubstantiated rumours.
And yes, there's a third-party Ogg Vorbis QT codec if you're that way inclined
So, if it were a comparison of MP3 encoders, would you also want a comparison to ogg or AAC? What's the point? It's incredibly useful to anyone who needs (or wants) to use AAC, and comparing to other codecs would only be irrelevant and a waste of time. If you feel left out, that's because it's not for you.
Perhaps you were looking for a "AAC vs MP3 vs Ogg listening test"?
...ask a stupid question, then reply with the obvious answer.
So one company has the best implementation of a mediocre, DRM-crippled, patented audio codec. So, why do I care?
And even if I gave in and were to buy AAC audio on-line and even if I could use the best AAC implementation and even if that were better than some other codec, I'd lose that quality anyway when converting that AAC audio format into a more usable format.
"mostly audiophile gear is a jerk-off session of wannabee music expert wealthy bast^H^H^H^H guys who can afford to spend large anounts of money on equipment"
And this differs from computer hardware discussions how?
How do you think Tom's Hardware looks to most people?
You were mistaken. Which is odd, since memory shouldn't be a problem for you
however, all of those quotations you've 'collected' are found at http://home.cfl.rr.com/happysurfer/audio_bs.htm
Pah! Balanced lines are crap. Before transistors, the concept was justifiable. Mixers were invariably passive, and it was common to use multi-ganged pots to attenuate both halves of the balanced line whilst correcting for the impedance change. Frequency equalisation networks also were passive. Amplifiers were mainly single-stage; pentodes for high gain, triodes for just about everything else, and required coupling transformers to unbalance the differential signal.
These days, it's possible to make such low-noise kit, and get away with ridiculously low impedances {just a few hundred ohms as opposed to a near-open-circuit} internally, that the balancing and unbalancing stages are actually the biggest noise sources in balanced kit. Unfortunately, there's too much legacy balanced kit out there; and probably always will be till digital finally buries it under a fixed and tolerable level of noise.
Je fume. Tu fumes. Nous fûmes!
Actually, one of the purposes of this test was to weed out the best AAC encoder for participating in a future test that will compare it to MPC, Vorbis, MP3, and WMA. The discussion of this test can be found over at the Hydrogenaudio forums.
Just how many more audio codecs do we need??
Cut to the chase please.. I use LAME at high enough bitrates to be pleased with the results. I don't care about squeezing bitrates down further while trying to get the best results possible. I'm happy with 'high' bitrates (160 or more) and can get 1000s of tracks onto harddisk based systems. AAC is of no concern, right? At higher bitrates the codec issues are different to those concerning small bitrates, are they not? I can carry on as before?! :o)
From the Aug 1995 Wired (http://www.wired.com/wired/archive/3.08/thompson. html)
Consider the music retailing system as it exists today. You go into a store, purchase a disc, take it home, play it, and put it on a shelf. It's no different from the way people bought records 70 years ago.
Now imagine something slightly more convenient: a music database on a computer, cross-indexed by artist, date, and song title. Imagine that when you click on a song, you hear it immediately, straight from your hard drive to your stereo.
There's only one snag in this scenario: Digitized music eats a huge amount of disk space. The sounds on just one CD require 600 to 700 Mbytes of storage. So Thompson looked for a way to compress music and conserve space.
But Thompson found the answer right next door to his workspace at Bell Labs. "The acoustic research department here has been doing pure research on and off since the '20s," he says. "That was when Western Electric used to do the soundtracks for movies. They told me they had a good algorithm for compressing music. I looked at what they had, and -"
He shakes his head ruefully. "They're acoustics people, not computer people. They were using Fortran. Original, monstrous Fortran. I reduced the algorithm's size by a factor of five and sped it up by a factor of hundreds and then started encoding music with it."
Most of the original research work was done by Jim Johnston, under the guidance of Joe Hall and Jont Allen, two other Bell Labs scientists.
Johnston freely admits that his early efforts were less than elegant. "It took me two years to develop the basic algorithm;
I was hacking it 95 ways because I was working in the dark. Then the Fortran was translated into C language, 5,000 lines became 26,000 lines - and Ken Thompson came along and assassinated the whole mess."
Collaborating with a young programmer named Sean Dorward, Thompson rewrote the code - it still performed the same task, but it ran in real time. In other words, the decompression program no longer took an hour or more to unlock two minutes of music; it could keep pace with the music, running in the background while the music played. Without this development, the system would have been unmarketable.
Sitting at his workstation under the watchful eyes of the pink plastic flamingos, Thompson turns back to his video monitor and clicks the mouse button. The crooning of the Everly Brothers lapses into silence. He scrolls through a huge list of songs, clicks on another at random, and something by Enya starts to play.
The original CD has been compressed and stowed on a massive storage system in the next room - a stack of 50 12-inch laser-discs able to hold a total of 300 Gbytes.
But the song could have been stored just as easily on the hard drive of a laptop - using Thompson's system, it has been compressed to less than 8 percent of its original size. (A Sony MiniDisc compresses music to 20 percent of its original size.) Nevertheless, the sound is still fresh and clean, indistinguishable from the original.
Apparently, you missed the discussions on whether the P4 or PPC 970 is faster.
Makes the audiophile rantings look sane.
Whilst the listening test is interesting, look at the styles of music tested:
1) "Rock"
2) Solo Harpsichord
3) Quiet intro with acoustic and electric guitars followed by loud metal riffs
4) IDM [??]
5) Electronic mix
6) Metal, complete with screeching vocals
7) drums and bass in the far left, guitar in the far right. Female vocal in the center.
8) rock/metal riffs
9) Drums and ride cymbals intro, followed by bass and female vocals.
10) Intro consists of guitar in far left with male vocal in center.
Hardly a broad range of music! This test tells me essentially nothing about which encoder would be best for piano music, orchestral music, opera, jazz, speech, etc.
Apples , i would imagine have much nicer audio hardware than your average PC. How can they be sure that the quicktime results aren't skewed by the nice speakers and soundcard on Mac's??
Electronic Music Made Using Linux http://soundcloud.com/polyp
What planet exactly have you been on the during the last decade?
(Hint: MultiMedia architecture invented at Apple in 1991, also the base format for MPEG4) more info..., even more info...
Yea, I used to drink a lot of orange juice but unfortunantly I damaged my esophogus from the resulting heartburn. Now I am forced to drink this stuff that doesn't have any taste called "water." No more cokes and coffee either. At least I don't have acid reflux anymore.
Wow...more useless audio formats compared....
When can we expect a test of 2400 baud modems to be completed? No, wait, I hear you. No fair saying the test is irrelevant because it doesn't include Cable Modems, DSL, or those flashy 14,400 baud US Robotics modems.
I think even if this WERE an article about comparing all these formats your post would probably be redundant.
The article claims the QuickTime audio format as a clear winner. Yet in most graphs the 95% confidence markers overlapped with other formats. Most statisticians would then say "Not Enough Data!!"
OK The results suggest that Quicktime was better but its not a clear winner until the 99% confidence intervals don't overlap, let alone the 95% ones. As one other poster said. You need a bigger sample size.
well, I guess the results make sense on this one, seeing as how apple is the foremost user of the AAC format. If the itunes music store was going to fly, the quality of their encoding had to be up there.
does AAC get much use outside of the apple world? I'm curious. As an apple user I have a degree of tunnel vision... Is AAC seen as an alternative to WMA for windows users or even MP3?
Could Jesus microwave a burrito so hot that he himself cou
The guy talks the talk, going into detail about ANOVAs etc., yet it's clear he needs to take a basic stat class. His conclusion is that Quicktime is the obviously superior approach. In fact, his ANOVAs expressly show that Quicktime is NOT statistically significantly superior to any of the other methods except for FAAC. Note that the confidence intervals are all overlapping. There's no there there.
Plus, what's with the separate comparisons and then the joint comparison? Is this an orgy of bad stats or something?
Possibly more important than the encoder for most people is the DECODER. Keep in mind you need software to do that, too.
Did most people just use Quicktime to play these? Might explain why QT did so well.
I have done many scientific blind ABX tests comparing lossy codecs to lossless codecs. I will not even think about using AAC until it sounds better than FLAC or Monkey's Audio. In my tests the .wav files sounded a little better than the FLACs and a lot better than the AACs. I made sure no replaygain or other things were enabled in FB2k. What we need is a lossless codec that is larger than the wav file, only then will it sound better.
The article states (near the bottom) that the files used in the test were encoded using iTunes' `best' setting, while iTunes uses the `better' setting. Presumably, this only affects the amount of time taken, since it's all 128kbps anyway.
Now, does anyone know how to encode using Quicktime's `best' setting? I have Quicktime Pro 6.3, which is supposed to have an `enhanced AAC encoder', but I see no difference in iTunes' preference panels. I've assumed that the encoder has been transparently upgraded, but have no way _knowing_ this to be the case.
Hope someone here can shed some light. And also, yeah, I can't tell the difference. I just wanna know.
Nonsensical metaphors from know-it-alls who half-understand what they're talking about...
First of all, AAC is developed by Dolby and Dolby patented the bulk of the technologies involved. Secondly, AAC is now part of the MPEG-4 standard controlled by the Moving Pictures Experts Group (MPEG), which Apple is a *member* and licenser.
Apple does not control AAC. There is nothing stopping someone from making an AAC encoder/decoder for Linux aside from the MPEG-4 licensing fee that Linux users are probably too cheap-ass to pay.
I think OGG as a format sounds the best out of the whole lot but until I can play it on my audiotron, there is no way i can convert, short of sticking a computer in my living room and carrying my laptop around a walkman. He are my two wishes:
Although this is offtopic somewhat, a lot of slashdot readers will find this interesting.
.ogg won every test but above 128 kb/s (kilobyte?) none of the codecs were clearly distinguishable from the original CD recording. Second best was AAC as far as I can recall and AAC was better than MP3 especially at the low bit rates.
The deeply respected German computer magazine C'T did a thorough, double-blind test of multiple codecs.
Germans are known for being thorough and this test proved that to me. They had studio technicians, musicians, a blind guy and a twelve year old (kids hear more sounds than adults). As I said it was a double blind test in a proffesional sound-shielded recording studio with both professional- and semi professional audio equipment and different kinds of audio.
To make a long story short,
It's free as in beer.
Just because a bunch of people got to togther and wrote their own source base does not mean the algorithms this code uses aren't covered by patents.
I don't like software patents either, but at least I understand them. Those who created Ogg Vorbis seem to have zero understanding of them.
There are three speed/quality settings in QuickTime. The first is fast and cheap, and really only meant for real-time broadcasting. For this, we're interested in "Better" and "Best" modes. The only real difference between then is when working with more than 16-bit source. Better uses every quality optimization technique that works when the source is only 16-bit. Best uses additional techniques that improve quality with higher bit sources (like 20 or 24 bit, common in audio mastering).
iTunes is tuned for CD ripping, so using "Better" mode by default is just fine.
AAC-LC can also decode at more than 16-bit in some implementations. This means it's possible to make a AAC-LC encode that is better than CD quality, if the source is more than 16-bit. I gather Apple does this with the iTunes music store, using better than CD quality masters for the encode when available.
My video compression blog
Actually, if you're doing low bitrate speech in Windows Media, you'll be a lot better of with Windows Media Audio 9 Voice. WMA is meant as a general-purpose codec. Low bitrate speech codecs are a different beast.
AAC-LC does somewhat better than stock WMA at low bitrate speech in my experience.
My video compression blog
The higher the data rate, the more transparent the encode, so differences between codecs will shrink. Since 160 MP3 sounds "close enough" to lossless for most listeners, there isn't that much room for a better codec to pay off. But while I can't really listen to 128 MP3 for for, 128 AAC-LC sounds great, even though headphones. And compare them at 96 Kbps at 44.1, the difference is huge.
My video compression blog
The problem with audio transmission standards is that they have NO built-in error correction, and operate at the limit of their bandwidth. So your nice, perfect square wave tends to get all muddy and round, like when you overclock your RAM too far.
People should forget about building better cables, and build a better communications protocol. Raw samples defeats the whole point of using digital comms.
A huge percentage of audiophile nonsense is focused on speaker cables, and thus far no double-blind test has shown a discernible difference between speaker cables, unless you are comparing with some particularly horrid wire you purposedly made as bad as possible.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
AAC is supposed to offer "Improved compression provides higher-quality results with smaller file sizes"
ok then why is when i convert a 44khz 128kbps CBR MP3 to a 44khz 128kbps CBR MP4/AAC that the file size is rarely smaller by a few bytes and usually larger by a few bytes?
Am i missing something? I'd like to convert my MP3's to AAC's if i could save space but that doesn't look to be the case on average.
MoRe... LaTeR... -=PJK=-
Just to make it clear why you can't do this: There is a certain incremental difference in subjective quality, that will cause listener A to rank something 4 instead of 3, for example. Will that same incremental difference in subjective quality case listener B to also rank something 4 instead of 3? We don't even know if the scale is linear, much less whether the different increments are even the same for different listeners.
Example: on the Kuro5hin blog site, if I really like a comment I will rate it 5. If I hate it, I will rate it 1. I never use the ratings in between. Thus, sometimes a 1 is bad, and sometimes a 1 is really bad. The same could happen here. Even if different listeners perceive similar subjective changes in quality, they might assign different changes in rank to those changes in quality.
God, this entire thing is bullshit, now that I think about it.
The biggest problem with AAC is that lack of support from the stereo device category. Maybe Apple should whip something up?
You know, what surprised me most about this report is the apparent relevence of Black Metal to the field of perceptual audio quality testing.
Sure, if you want to say "Codec X is a 4.8/5" then that's meaningless. However, if the SAME PEOPLE rate X at 4.8 and Y at 4.6, we can say that X is better than Y.
To restate, we can't know anything about the absolute quality, but the relative quality between codecs is what we're interested in.
Thanks,
Peter
What a glorious non-sequitur. You've demonstrated that you can't extract a ratio level of measurement (e.g. number of incidents of an occurrence) from an ordinal level of measurement (e.g. satisfaction ranking). What you've alleged is that the tester claimed that Quicktime was 2.45 times as good as FAAC (substitute another bogus number if you want). He did no such thing. He only relied on the idea that everyone in the testing group thought that 2 was worse than 3 and better than 1. Everyone in the group shared that thought. He's saying "four out of five testers prefer X to Y".
A great number of statistical functions can be performed on ordinal data sets, including averaging, ranges, and I believe standard deviations and degrees of significance. I'm pretty sure you can even code Yes/No questions into one and zero and perform them.
What you say about not being able to perform statistical analysis on subjective data is complete nonsense. Back to stats class.
Linux will support AAC as soon as a company or indvidual is willing to lisense the codec and write a encoder/player that uses it. Perhaps if more people purchased commercial software on Linux developers would be encouraged to create more of it.
If you mean the MPEG 4 consortium isn't going to open source their technology any time soon you are probably right. Apple, if you will recall, fought an agresive media campaign to get the lisensing terms down to a reasonable level. This delayed the release of QT6 by a few months, but enabled free non-profit streaming of the codecs.
This was talked about on Slashdot here back on July 18, 1999. There is mention of licensing by a company called Lydstrom that are no longer on the net so I assume they are dead. There is a legal filing from March of 2000 here from a company called e.Digital where they are licensing the PAC (or EPAC) technology from Lucent, but the rest of their site does not indicate their use of this in any of their products. The compression algorithm appears to be totally proprietary to Lucent, inherited from Bell Labs, so it's probably of no real interest to most Slashdotters.
Some days it's just not worth chewing through the restraints.
Look at some of the titles they picked: Artist: Cradle Of Filth Title: Beauty Slept In Sodom Artist: Opeth Title: Blackwater Park Artst: Tiamat Album: A Deeper Kind Of Slumber These three all had rather high scores with a lower standard deviation. A good percentage of listeners can't tell apart guitar distortion (especially really heavy ones) much apart from each other. In fact, metal is the hardest of all genres to compress with the best quality because of the high entropy (don't tell me double bass drums and shrill screams from some castrated puppy like Dani Filth don't have high entropy). I find it hard to believe that so many people could give such high marks (quite near the max possible) to metal without being a diehard metalhead (and even then some think the compressed ones sound better than the original). They are all good recordings, but the problem that I see with the selections is the lack of dynamics - the #1 problem in modern metal music. Opeth well... I'll take Maudlin of the Well (or whatever that band is now called) over them.
But will PAC be included in the next phase of the competition, which compares the best AAC encoder with at least the best MP3 encoder, the best Ogg encoder, and the best WMA encoder?
Will I retire or break 10K?
where's country and disco?
Country in the 2000s is just American pop sung by somebody with a "country" accent. Disco has become house, which could form part of the "electronic mix".
Will I retire or break 10K?
I may be late to add this, but HydrogenAudio has just begun the second testing phase. See the announcement page. "Building on the AAC at 128kbps test results, this test is meant to compare the AAC winner (QuickTime) against other popular compression formats: Musepack, Vorbis, WMA Pro and MP3." Submit your results by August 3.
For a real world multi-format test you might check out:
l
http://www.recordstorereview.com/misc/aacmp3.shtm