Where can I find some general information about AAC? IE, what's it's origin, does it have any licensing/patent restrictions like mp3, what's the best encoder/decoder, how does it compare to say, Ogg Vorbis, etc..

AAC was developed by the AudioCoding industry giants (FhG, Dolby, Sony, Nokia and AT&T, mainly), over the base of MPEG1 audio (mainly MP3).

Development started at the beginning of the nineties, and hasn't stopped yet - non-destructive improvements to the standard are still being added, and MPEG-4 Audio v3 is probably going to be standardized at Q1 2003, with improvements such as SBR (AAC+) and new profiles.



Actually, it's much worse than MP3.



The best encoder is supposedly FhG AACdemo 2.2, but you will have a hard time trying to find it around.

The best freely available encoder is undoubtedly Psytel AACenc 2.15

The best decoder is probably FAAD2. It's very fast and has excelent quality.



Depends mostly on the bitrate range, the sample, etc.
And, in AAC case, it depends a lot on the encoder used too.

Talking AACenc vs. Ogg, generally ogg wins by a large margin on low bitrates (AACenc isn't well tuned at those bitrates), and AACenc usually wins on high bitrates. But, as I said, depends a lot on the samples used.

Regards;

Roberto.

Edit: Good link to get more info:
http://www.audiocoding.com/wiki/index.php?page=aac

http://www.aac-audio.com/Licensing/

http://www.aac-audio.com/licensing/LicensingFAQ.html

12c for "Consumer Decoder" shoudn't effect hardware players pricing too much.

I was taught by my chemistry teacher that you can't say "a catalyst affects the reaction speed" because the catalyst doesn't have affections towards the reaction... so for non emotional things, you can only have effects not affects

Back to the original point... I am wondering how well AAC could be at the lower end? I know AACenc has been tuned to rival the best encoders at high bitrates, but.. could it rival OGG at low bitrates with the SBR + time spent tuning? If so.. I think it would come off as the best all round encoder to date

rjamorim says,

"The best freely available encoder is undoubtedly Psytel AACenc 2.15"

Is this available only for Windows Machines (as implied by the .zip and .exe endings on the downloaded files) or can it also be used on a Mac?

Currently, I'm encoding AAC files using QuickTime 6 Pro, but (especially if a later version has SBR) it might be useful to try the Psytel encoder, if it's possible.

And do you think AAC-with-SBR will be available anytime soon in QuickTime Pro, or other Macintosh encoders? (Audion, maybe?)

Mike

I doubt that AAC+SBR will be availible by Apple soon. Things go slow with Quicktime. And i don't think "new innovations" and Apple go well together. Heh, they'd like you to believe they're the first who offered "high quality" multi-channel AAC audio production. While the Psytel AACEnc command line demonstration was availible so long before. Also, AAC files encoded by AACEnc v2.15 have higher quality than files encoded by Quicktime in my opinion. You can also check a comparison between the two. Comparison of constant bitrate 128kbps encoded files: Psytel, Quicktime. Second comparison of 64kbps encoded files (no SBR): Psytel, Quicktime. I hear obvious differences between the audio files, and the AACEnc encoded ones sound better to me.
Oh and, AACEnc can't be used on a mac..

Is it true that there's not going to be another release of the Psytel AAC encoder? I think I read that on some thread..

That's something I'm wondering too... or at least, if 2.15 is going to be the last free version available?

It will be the last availible command line demo, yes.
A newer, improved AAC encoder by Psytel, well, now Ahead, will probably be availible with Nero. In what way (buying it seperately, included without need to buy) is not known.
Maybe someone knows and can tell us?

Ahead sucks balls.. they'll include a free demo with Nero, then they'll want you to buy it. It's a damn waste of money IMO because it's only a plugin. I wouldn't mind if it was a command line program...

Windows-only for PsyTEL AACEnc v2.15, and as far as I know Nero does not provide a Mac version of its burner software, so you can't use Ivan's updates of his encoder, even if they are available via Nero.



As far as I know, Apple uses the Fraunhofer AAC codec, but I'm not sure which version. Maybe you could look it up somewhere? Because the newest version (evaluation build from Aug 23, 2002) did sound very good in the 64 kbps c't listening test (for my taste), but your version is probably older than that.



Like I already wrote, AAC+ will probably take some more months, before it will be available for the public. And QuickTime may integrate it, too, but my guess is that Audion would be quicker than Apple, because they already have a deal with Coding Technologies for mp3PRO.

So you should ask yourself if you really need these low bitrates that AAC+ seems to be very good at (like 48 kbps), or if maybe 64 kbps is small enough for you, because then you can encode your analog tapes with mp3PRO, too. If you rather consider 80-96 kbps as a sufficient file size/bitrate, you should do some own comparisons between QuickTime 6 Pro and mp3PRO with Audion 3 (if you have access to this software), because normal AAC has its "sweet spot" at this bitrate (the best efficiency compared to other formats).

hans-jurgen says,


Would it be easy for Apple to incorporate a newer codec (like this one) into QuickTime6-Pro by just including it in a downloadable version-updater? Or is it more complicated than this?

Sorry, I don't know QuickTime and Apple's update policies. The best idea is always to ask the company to do something about it, if you are sure that the codec is outdated in your application - especially if you paid for it...