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AAC vs. OGG vs. MP3
asv108 writes "Yesterday, Apple unveiled their new music service claiming that the AAC format "combines sound quality that rivals CD." Here is a little comparison of lossy music codecs, comparing an Apple ripped AAC file with the commonly used MP3 codec and the increasingly popular OGG codec. Spectrum analysis was used to see which format did the best job of maintaining the shape of the original waveform." Wish they had WMAs in there too. And for the spoilage, it looks like OGG comes out on top.
"the increasingly popular OGG codec."
sadly, I don't think OGG is *currently* known to anybody except nerds or IT pros.
Most people who use ogg do not use it for it's quality. All that matters in that respect is that Ogg is comaprable to other formats at similar bitrates.
The important aspect of it is that it's free. There are no patents (at least as far as we know of) preventing anyone from using it, and it's made quite clear that the code can be included in open and closed source software without royalty payments.
I spent some time last night playing around with the new Music Store feature in iTunes 4. Besides the fact that iTunes crashed on me twice, and 3 never crashed on me, it seems like a very well put together feature.
What kept me from buying the dozen or so tracks I found that I thought were worth a buck a pop was the fact that my Rio Receivers need MP3 or, via "upgraded" software, FLAC, etc... Although the AAC->CD->MP3 route is possible, and I intended to buy a track and see how the quality comes out, has anyone seen anything about how the DRM works on the Apple files?
I'm wondering if there are any libraries out there for decoding them, even within the confines of the DRM... just so I can get them into either a raw data stream or something so I can play them on my Rio Receivers... I'd probably switch to buying all my music (where possible) from them, if thats the case... but if I can't get them into a format I can play using my existing equipment, I'll have to pay the five buck "CD"-tax to get them in a format I can rip to high-bitrate MP3.
I don't think graphs are all that useful for comparing lossy sound compression.
Microsoft likes to show how their wma looks better than the other compression methods... it does look beautiful in graphs, but it sounds all tinny and horrible.
I don't care if the compressed frequency response graph looks nothing like the original frequency graph, as long as my ears are unable to tell the difference between the two.
Will people please stop talking about Ogg as though it were an audio compression scheme. It is not - it is a wrapper format.
I don't care what kind of tests were done, but anything comparing Ogg to a lossy compression scheme is bound to be unfair, as the Ogg family includes a lossless encoding scheme. Not only does Ogg include FLAC and Vorbis, but it also includes Speex, targetted at voice, and Theora, a video codec.
So please, stop trying to compare Ogg to MP3. It's like comparing AVI or Quicktime to MP3.
To do a true test, you need to encode the files, decode them to PCM wav format, then burn to an audio CD. Then, you have to do a blind test with all of them. You also need to use a variety of source material, because different genres of music compress better under some encoders.
If you have to do all that to tell the difference, doesn't that kinda tell you something?
That's there value in ruling out variables when trying to objectively compare things?
Well then that bolsters my original reaction, which is that regardless of the original source of these 'test samples', you'll be hard-pressed to lease the master and rip directly to .ogg or .mp3 like Apple has done with the AAC's available off their service.
I hate Grammar Nazi's
Yes, until someone gets sue happy and starts suing MP3 and AAC users. Maybe it will happen, maybe it won't.
Look at GIF, JPEG, and PNG. GIF is used for its quality, JPEG is used for its size, PNG is used by geeks. Unisys started suing webmasters, now the patent holder for JPEG is ruffling feathers, PNG is slowly becoming the accepted format. All it takes is some greedy SOB to make Ogg an attractive format.
There is no reasonable defense against an idiot with an agenda
:wq
> Is it that difficult to grasp! Ogg is a container file! Vorbis is the audio codec!
IT DOESN'T F'ING MATTER!
Just like Linux isn't an OS, (it's a kernel) no one aside from you and some other geeks (not meant as an insult, I am a geek too, obviously) will ever convince others of the truth.
More importantly it doesn't even matter. The details are subtle and by continuing the geeky "I'm better than the stupid lusers" all you are doing is keeping Vorbis from becoming more popular -- people will become pissed off that they get hassled every time they mention it, and then ignore it in the future.
Can you point out one player? Because I've never seen them.
Yep. The 5GB iPod I bought over a year ago plays AAC encoded files (after installing the v1.3 Firmware Update), as do the other 700,000 iPods out there. Combine that with the new Apple music store, and overnight you've got a whole lot of AAC encoded music out there with hardware support.
AAC/MP3/OGG are all based on psychoacoustic models. Comparing their decoded spectrums is pointless. The spectrum isn't supposed to be faithfully reproduced. Frequencies that your brain wouldn't fully hear aren't fully stored.
The only value I can see in a spectrum comparison would be to find obvious errors in the encoder or decoder. Like the 16kHz spike in the Xing encoder. But how likely is that going to be these days?
The only proper comparison involves a good hi-fi, a sensibly furnished room, and a comfortable chair. It is called "golden ear" testing and it's the ONLY way to compare psychoacoustic models.
Or at least it's the only way until the research scientists work out how the human brain works.
My favorite part of this discussion is where slashdotters believe that they, the open source community and Ogg in particular are foremost in the minds of people like Steve Jobs as he unveils his new music service.
Get a clue already. Apple went with AAC because it's great quality, supports the (fairly mild and necessary to get the RIAA onboard) DRM restrictions for the service, and is a subset of the excellent MPEG4 video codec.
Even if Ogg is better quality at lower bitrate (a point that I am not convinced of, "waveform comparisons" notwithstanding), Apple has legitimate reasons for going AAC that have nothing to do with The Man trying to keep you and the open source community down. Jesus, it's not always about you, mkay?
You like your Macintosh better than me, don't you Dave? Dave? Can you hear me Dave?
Learn why you shouldn't use spectral analysis to determine lossy codecs' quality.
The most respected technique is double-blind testing using an ABX tool such as PC ABX, WinABX or ABC/HR.
More info on conducting blind tests can be found at the PC ABX site.
Use ISO 8601 dates [YYYY-MM-DD]
Modern compressions schemes are supposed to make sound that sounds as much like the original as possible, not looks like the original on an FFT.
The only way to test this is to use double-blind listening tests. The spectral analysis stuff is absolutely useless for finding out how good the music actually sounds.
autopr0n is like, down and stuff.
Even then you would probably have to be selective. Rich orchestral works (say, Janacek, Mahler, Sibelius) won't show an obvious difference, but something more spare (e.g. Debussy string quartet or a good recording of baroque strings) will show a big difference that should be evident even on poorer quality equipment.
CDs have flat sound to begin with when compared to analog masters. So in order to get "better than CD" quality you would have to rip from the master tape. Also, file size would have to be less than 60mb per song. (size of a 5 minute uncompressed song from a CD) :)
While most master-to-CD transfers sound fine, classical music tends to lose its "warmth." I am no audiophile but I noticed a big difference when I listened to Crux Shadows live and on CD. Speaking of audiophiles, by the time they can afford to buy their must-have equipment, they've already lost their hearing. Give them 128kps mp3 file stamped on vinyl and will swear it sounds better than your original CD
A decent, but simplistic article. Unless you're a fussy audiophile, this analysis should be sufficient for you.
[rant] I wish the author would present his graphs in a more readable way. A screen dump of Photoshop in WinXP is not a professional way to show data. It's ironic that while reviewing lossy audio formats he opts to use a lossy image format (JPEG) for the graphs. I had to double their size on my screen just to make some sense out of them. [/rant]
It's not difficult to gain better-than-CD quality. CDs have been around since the early 1980s, and their main drawback is that they have a low sample rate, 44.1KHz. This is why many sound engineers prefer vinyl. because it's an analogue format, vinyl has a potentially infinite sample frequency range (although it's obviously limited by the recording and playback equipment, and by the physics of the media itself). Apple has used original masters (not CDs) to create much of its song library, so all they have to do is encode at a higher frequency than 44.1KHz. At a guess, they're probably using 48KHz, which is on par with DAT and MiniDisc.
I'm not surprised that Apple is using AAC. For one thing, it is clearly better than the decade-old MP3 format in all respects, and the licensing costs are probably the same or better. Technically, it may not be as good as Ogg, but most people don't even know what Ogg is so it doesn't matter. As long as Apple can say "our format is better than MP3 and CD audio" (the two prevailing formats), they will have the attention of consumers. AAC is a more mature format than Ogg (Ogg isn't bad, but AAC is more tried-and-proven), and is probably more compatible with existing DRM technologies. DRM is important to keep the recording companies happy and to ensure that the files will only play on devices that Apple specifies (like on Macs and iPods).
A major stumbling block for Ogg is that until fairly recently it was necessary to use a floating point processor to play the format. In the arena of portable devices, only PDAs have floating point capability, which is why you can play Ogg files on your Zaurus and not on your iPod. AAC is already supported by many devices, so Apple has a larger potential market (although at present only iPods can play the files).
OLPC Australia
If the musicians like it that way, they should record it that way. Sound reproduction equipment should do just that -- reproduce as accurately as possible the sound on the CD (or other source)
If people deliberately want to alter the sound, that should be done by effect processing that can be turned off, but not built in by inherent limitations in the reproduction equipment.
Now, if you are interested in sound production, that is another matter entirely. The sound of a (say) guitar amplifier is as much a part of the musician's instrument as the guitar, though it would still be nice if a lot of that load could be taken off of unreliable power amplifiers and placed on reproducable, removable low level effects processing.
It's an easy install which the average Windows user would perform if so directed.
.ogg file that they've somehow come across and double-clicked on. At this point they will be out of their depth, they'll click on cancel and get on with their lives - ignoring .ogg files from now on, because 'they don't work on my PC'.
Why is everyone so determined to miss the point? Yes, there are a dozen ways of adding Ogg/Vorbis support to Windows. They vary in complexity.
Support is not available by default, therefore your average non-technical Windows user will get a window popup asking them which application they want to use to open the
Spectrum analysis was used to see which format did the best job of maintaining the shape of the original waveform
Will people ever stop doing that. It's complete bullshit and certainly not the way to evaluate a codec. These codecs use perceptual weighting of the noise. That means that the idea is to distort the signal as much as possible in any region of the spectrum where it won't be heard at a certain time. That means that you see a big distortion in the spectrum and think the codec is worse than the others when in fact it's better because it realized that it doesn't matter.
The only way to correctly evaluate a codec is to listen to it. I write codecs (see sig), so I know a bit what I'm talking about. I use spectral analysis sometimes, but only to identify problems which I've already heard before, not to say that my codec is good.
As a aside, I'd say it probably wouldn't be hard to write a codec that does better than any other on those spectrum analysis. They would sound like crap because their psycho-acoustic model would be all wrong.
Opus: the Swiss army knife of audio codec
Palm OS 5 PDAs (Zire 71, Tungsten T) only have integer ARM CPU's, and they play Ogg files just fine (running AeroPlayer or PocketTunes). And the Apple iPod uses a very similar ARM CPU core.