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Topic: Is AAC "transparent" at only 192 kbps? (Read 9093 times) previous topic - next topic
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Is AAC "transparent" at only 192 kbps?

Are these two quotes telling me that AAC is transparent at 192 kbps?

From AudioCoding.com's AAC page

Quote
Pros of AAC:

Transparent quality is possible (e.g. with the -extreme preset of PsyTEL AACEnc) which means that most of the test samples are indistinguishable from the original for most of the listeners (term defined by the EBU in 1991 and statistically implemented in their formal listening tests since then).


And then from their PsyTEL page

Quote
Preset "-radio -resample 32000" for low bitrate encodings at 70-80 kbps, equal to mp3PRO at 64 kbps (suitable for modem transfers, AACEnc only!)
Preset "-internet -resample 32000" for bitrates at ~100 kbps (most interesting for 8cm CD portables like the Philips Expanium 401, AACEnc only!)
Preset "-streaming" for competing with every other codec at ~128 kbps
Preset "-normal" for very high quality in the 160 kbps range
Preset "-extreme" for those seeking for that ultimate "transparency" and never found it at ~192 kbps
everything above for the absolute "peace of mind", if nothing else helps...


Is there a noticable improvement at 256 over 192? Unfortunately, I'm sick, or I'd do the listening tests myself, and I have about 20 gig of AIFF files on my computer I'd like to encode as AAC files because I need the hard drive space, but I don't want to sacrifice much (if any) quality. Thanks

Is AAC "transparent" at only 192 kbps?

Reply #1 –
AAC at 192kbps should be transparent on most samples. It would probably only fail on problem cases. (At least for me - YMMV)

Is AAC "transparent" at only 192 kbps?

Reply #2 –
For people using iTunes AAC; 192kbps isn't transperant. I'm not quite sure that even 320kbps is...

You should be aware that AAC artifacts aren't the same as MP3 artifacts; they're more similar to Ogg Vorbis artifacts. It's sort of like a more shallow sound.

Is AAC "transparent" at only 192 kbps?

Reply #3 –
I think the Psytel site is trying to say that you really should have found transparency by 192kbs, anything above that is really just academic changes for most of us.  I found it below 120kbs..  so really, it's a test of your own hearing
< w o g o n e . c o m / l o l >

Is AAC "transparent" at only 192 kbps?

Reply #4 –
Quote
I think the Psytel site is trying to say that you really should have found transparency by 192kbs, anything above that is really just academic changes for most of us.  I found it below 120kbs..  so really, it's a test of your own hearing

I think Hans-Jürgen wrote that text. So, these are only his opinions, really. (Although I share them)

Is AAC "transparent" at only 192 kbps?

Reply #5 –
Quote
Are these two quotes telling me that AAC is transparent at 192 kbps?

Frank Klemm's made a claim that a perfectly tuned AAC encoder could be transparent at around 120-130 kbps. It's just that no encoder's even close yet.

Is AAC "transparent" at only 192 kbps?

Reply #6 –
Hmm, so why don't we use AAC then? I mean for what do we need ogg? Before people switch from mp3 to ogg it would be much more wise to stick with AAC, right? Also, how is this possible? I mean the developers of lame; wma or ogg are already fiddling for years to reach that goal...
--alt-presets are there for a reason! These other switches DO NOT work better than it, trust me on this.
LAME + Joint Stereo doesn't destroy 'Stereo'

Is AAC "transparent" at only 192 kbps?

Reply #7 –
Quote
Hmm, so why don't we use AAC then? I mean for what do we need ogg? Before people switch from mp3 to ogg it would be much more wise to stick with AAC, right? Also, how is this possible? I mean the developers of lame; wma or ogg are already fiddling for years to reach that goal...

Well, the primary original purpose of the Vorbis codec was to be patent free and completely open (with "it's better than MP3" being a nice secondary benefit).  Thus it can be used anywhere without license fees; this is why it's quickly becoming a popular choice for audio in computer games (there's no reason for the game company to pay licensing fees for MP3 or AAC when they can use Ogg instead).

As for AAC vs. other formats, it'll take a while to see how it plays out.  It's probably the case that MPC on average is transparent at lower bitrates than AAC currently, though Frank Klemm's page seems to indicate that AAC is theoretically transparent at lower bitrates than MPC if it were tuned properly.  I don't think many people here seriously follow WMA, so there's probably not much comparison being done there.  As for LAME, the developers have been doing a great job there, but the MP3 format is saddled with a lot of baggage that simply makes it unable to compete with the newer formats past a certain level.  They do have *much* better tuning than all other codecs I know of though, which allows MP3 to be surprisingly close currently despite its inherent weaknesses.

Is AAC "transparent" at only 192 kbps?

Reply #8 –
Quote
Hmm, so why don't we use AAC then? I mean for what do we need ogg? Before people switch from mp3 to ogg it would be much more wise to stick with AAC, right? Also, how is this possible? I mean the developers of lame; wma or ogg are already fiddling for years to reach that goal...

Dou you like Fraunhofer encoder quality and possibilities? Or do you use LAME?
Fraunhofer made very small evolution (comparing LAME) and IMHO this situation will repeat on every commercial encoder. They will stop development after 70% of people say IT IS TRANSPARENT. I am not in that 70% (Note that almost all that 70% believe that transcoding makes music sound better  ). 2nd. I think Vorbis need us to continue development. If we all chose AAC-we will get AAC monopoly in some years(but maybe in 3-4 years people will completely forget about loseless compression  due Blue Ray and e.t.c?). I don't think it is good.
Ogg Vorbis for music and speech [q-2.0 - q6.0]
FLAC for recordings to be edited
Speex for speech

Is AAC "transparent" at only 192 kbps?

Reply #9 –
Quote
As for LAME, the developers have been doing a great job there, but the MP3 format is saddled with a lot of baggage that simply makes it unable to compete with the newer formats past a certain level.  They do have *much* better tuning than all other codecs I know of though, which allows MP3 to be surprisingly close currently despite its inherent weaknesses.

Please don't forget about LAME 4.0!!!
I If everything will go right it woulde be the fastest High Quality Codec.
I hope Takehiro will do it
Ogg Vorbis for music and speech [q-2.0 - q6.0]
FLAC for recordings to be edited
Speex for speech

Is AAC "transparent" at only 192 kbps?

Reply #10 –
Quote
For people using iTunes AAC; 192kbps isn't transperant. I'm not quite sure that even 320kbps is...

Out of curiosity, what's wrong with the iTunes encoder? It's the only one I have, so I don't have anything to compare it to. In the comparison test, it did pretty well, which can be found here. Does using the encoder from within Quicktime give any benefit, I know it offers many more options.

I'm not trying to archive original music here or anything, I'd just like to be able to listen to it on my NAD/Klipsh stereo system. And actually, my Sennheiser 600s and Creek OBH-11 are pretty damned revealing too. it sounds like 192 it is then, or does anyone think 256 would be worth the extra space? Thanks everyone, this place is awesome.

Is AAC "transparent" at only 192 kbps?

Reply #11 –
Quote
Out of curiosity, what's wrong with the iTunes encoder? It's the only one I have, so I don't have anything to compare it to. In the comparison test, it did pretty well, which can be found here. Does using the encoder from within Quicktime give any benefit, I know it offers many more options.

The main issue with the iTunes encoder is that it uses CBR, so there's some waste of bits. Other than that, I'd say it's pretty good at 128-192, but if you go above 192, LAME is virtually transperant anyway. The test you refer to used 128kbps; I've heard some samples from the iTunes music store, and although they sound good for 128, it's easy to hear that they've been compressed.

Is AAC "transparent" at only 192 kbps?

Reply #12 –
Quote
The main issue with the iTunes encoder is that it uses CBR, so there's some waste of bits.

Oh, thanks, that makes sense. I guess I'll live with the CBR/VBR issue, although it is a shame that Apple has put that limitation, unless I missed something, it doesn't even look like you can use VBR if you go through QT 6.2 Pro even , oh well.
Quote
Other than that, I'd say it's pretty good at 128-192, but if you go above 192, LAME is virtually transperant anyway.The test you refer to used 128kbps;

So, for 128-192 AAC is great, but above that, LAME will still beat AAC? So here's a question, which is better in iTunes between say 192-256, AAC or MP3? I'm not looking for ABX tests or anything, just some general opinions. I REALLY want to use iTunes out of convenience, so, even if LAME is better at say 192, I'm going to use iTunes AAC at 192.
Quote
I've heard some samples from the iTunes music store, and although they sound good for 128, it's easy to hear that they've been compressed.

I have to agree with you on that, it's kinda mixed actually, some sound pretty damned good, but others sound kinda bad. I think a lot has to do with the source. I've only bought a few of the exclusive tracks, many of which are live, and they don't all sound so hot, but overall it's impressive, they're almost all better than 128 MP3s.

Is AAC "transparent" at only 192 kbps?

Reply #13 –
Let's all encode in AAC in the hopes that when the AAC encoder achieves transparency (no problem samples) our old files can be transcoded to sound as good.

Is AAC "transparent" at only 192 kbps?

Reply #14 –
Quote
Let's all encode in AAC in the hopes that when the AAC encoder achieves transparency (no problem samples) our old files can be transcoded to sound as good.

you are kidding, arn't you?
--alt-presets are there for a reason! These other switches DO NOT work better than it, trust me on this.
LAME + Joint Stereo doesn't destroy 'Stereo'

Is AAC "transparent" at only 192 kbps?

Reply #15 –
Quote
So, for 128-192 AAC is great, but above that, LAME will still beat AAC? So here's a question, which is better in iTunes between say 192-256, AAC or MP3? I'm not looking for ABX tests or anything, just some general opinions. I REALLY want to use iTunes out of convenience, so, even if LAME is better at say 192, I'm going to use iTunes AAC at 192.

at around 192 - 256 kbps, i'd say lame aps and aac will roughly have the same quality. however lame is free and mp3 is still king of compatibility, which makes it more convenient for me.

Is AAC "transparent" at only 192 kbps?

Reply #16 –
Quote
Let's all encode in AAC in the hopes that when the AAC encoder achieves transparency (no problem samples) our old files can be transcoded to sound as good.

lol
WARNING:  Changing of advanced parameters might degrade sound quality.  Modify them only if you are expirienced in audio compression!

Is AAC "transparent" at only 192 kbps?

Reply #17 –
Quote
I REALLY want to use iTunes out of convenience...

Then do.

Is AAC "transparent" at only 192 kbps?

Reply #18 –
Thanks blessings, I'll check it out, although as we speak, i'm encoding all the AIFF files on my hard drive to 192 kbps AAC files. I did some listening tests today using the problem samples given in the Tech (AAC) forum, as well as the Chesky Ultimate Demonstration disc (one of the best recorded things I've ever heard, with little introductions before each track as to what to listen for), and most importantly samples from each of the genres of music I actually listen to. Thank you all for your help, this place is great.
 

Is AAC "transparent" at only 192 kbps?

Reply #19 –
If ripping to AAC in iTunes, you may want to use this:

http://www.malcolmadams.com/itunes/itinfo/...minempeg4.shtml

The iTunes default encoder is set to "fastest" quality rather than "best," independent of the bitrate.  There is no way within iTunes to change this.  This script will allow you to use the QuickTime Pro settings instead, which allows you to choose the "best" setting.  Does it make a difference?  Probably.  If you are going to re-rip a bunch of CDs to AAC, you may want to check it out first.

If this point has already been beaten to death, I apologize (I'm newb!).  Great forum, I look forward to mooching off the wealth of knowledge here (and hopefully throwing in a good point or two when I become more knowledgeable).

BTW, all my CDs were ripped in LAME alt-preset-extreme.  I have a hard time distinguishing those from AAC at the 160 bitrate (128 is a little more obvious).  I'll probably re-rip everything to AAC 160.  Gotta fit more tunes on my iPod while keeping them sounding nice!