OS X 10.6 "Snow Leopard" is out today and sports some changes to the AAC encoder. From what I've seen so far, the 'true' VBR mode settings give different bitrates than the previous version, where q127 files now end up being >320kbps most of the time. It seems ~q90 is the equivalent to the old q127. I'm not sure if there are any major quality improvements to the encoder though.

HE-AAC support is now included too, but not yet in iTunes.. Hopefully it's set to be included in the next version of iTunes, which according to rumors will be released in a couple of weeks. That's probably when Windows users will get the new encoder too.

It'd be fun to see some listening tests on both the new HE encoder and also the regular one to see how it compares to QT 7.6.2..

interesting,can't wait to try it out!

Does the iPod App from the iPhone support HE-AAC?

The new XLD version that just came out supports it already!

I have played around with it a little bit and made some interesting observations:

The new Quicktime includes the first AAC encoder that masters the infamous Emese sample transparently! For my ears at least. Nero was never able to handle it even at the highest bit rates and also LAME and Vorbis have always failed badly. This only works at the highest setting of Q127; at Q122 with only slightly less bit rate I can ABX it instantly, which is kind of strange. ABR 320 is also transparent.

I hope that Apple finally opens up true VBR AAC encoding to iTunes. I would have tested out their true VBR AAC encoder more if it wasn't such a pain to encode on Windows. I am interested to see how it stacks up against Nero AAC as I have always been forced to use their VBR_constrained setting. I wouldn't hold my breath for HE-AAC support in iTunes or on iPods though. Apple seems intent on allowing users to access high bitrates. After all, the iTunes Plus encoding standard (256kbps, VBR_constrained, "high quality" setting) is now the default ripping/encoding setting in iTunes. HE-AAC support would benefit iPod shuffle and iPod nano users as their players have limited capacities (I consider 16GB and less to be limited especially whenever there are 120GB players floating around for only $40-$50 more). We will see what Apple does once their September iPod event rolls around. The current rumor is that it will happen on the 9th of September but Apple hasn't confirmed anything and likely won't until next week.

The new Q127 might be a good candidate for my collection. Still I would consider a >300kbps average a huge waste and would not want that. So I checked if there's at least some degree of economical sanity left in this mode and fed it an old shellac recording, that used to average at ~101kbps with the old Q127. It comes out at ~155kbps now, which is a waste since the 101kbps was already perfectly transparent, but at least demonstrates that the new Q127 mode does not stubbornly push >300kbps bit rates. I'll post some new collection averages later.

Last time I tried Vorbis Aotuv at 192 kbits it did better job than any other encoder for emese sample.

I wouldn't use HE-AAC even if I'd have only 1GB DAP. The quality drop is too big.
At least LC-AAC 96 kbit/s with true VBR+best settings.
I don't think people would sacrifice quality that much. I've already done some test around new HE-AAC encoder. For my ears it's better than Nero at 64 kbit/s.

Apple claims that new HE-AAC encoder at 64kbit/s is comparable with LC-AAC 96kbit/s.
Of course, it's not true.

Better or transparent? With "failed badly" I meant the inability to reach transparency at any bit rate. I have never actually tried the Aotuv flavor, though.

From my 6+ years on a different set of iPod related forums, people don't care. Most people open iTunes, plop in a CD, rip it, and copy the tracks to their iPod. They also use the supplied earbuds with their iPod. They don't care about adjusting the bitrate, which audio format to use, etc. These are the types of people that probably can't discern a difference between a 64kbps HE-AAC file and the source lossless material. After all, 128kbps (iTunes AAC, Nero AAC, Lame mp3) is transparent to them. Couple that with the supplied iPod earbuds and noisy environments, that makes 64kbps HE-AAC actually sound pretty tempting. Most people want to fit more songs on their iPods over sacrificing space with higher quality. The forums contained a bunch of posts complaining about how their newly ripped songs won't fit on their iPod. In other words, after Apple made 256kbps VBR the new ripping standard setting in iTunes, people were complaining that their iPods ran out of space much faster than before (when 128kbps "CBR" was the standard). Either that or people will just crank the setting up to 320kbps and move on. There really are only a handful of people that take the time to conduct blind ABX tests and mess around with the iTunes CD import/encoding settings (aside from going all the way up to 320kbps).

That is why I feel that a good chunk of people may benefit from HE-AAC. They will be able to encode down to 64kbps and fit more on their iPod nano (the most successful of the iPod line). Now, whether or not these people take the time to educate themselves is a different matter. I am a little disappointed to see Apple playing the numbers game. Microsoft did that back when they updated WMA (way back during the Windows ME/2000 days) and said that a 64kbps WMA file was equal to a 128kbps mp3 file.

I'm expecting my copy of SL to arrive sometime later this afternoon, so I'm looking forward to getting to test out these new improvements (or at least, the higher quality settings available now)... until then, where would be the best place to find a quality vs. average bitrate breakdown for this latest Quicktime version? I was used to -q 120 yielding files with an average bitrate of ~160kbps before, so I'm curious what setting I'd need to use now to get an equivalent average bitrate.

(will post my results later today after I've had a chance to test out the new encoder for a bit... can't wait, I already noticed the addition of HE-AAC to XLD's options with the latest update, so this should be interesting )

OT: What does the OS have to do with the capabilities or the version of an encoder?

For "Snow Leopard", read "QuickTime X"; I don't think the latter's available separately yet.

My whole collection (Jazz, Classical, Rock, Electronic) average with the new Q127 setting turned out to be 302 kbps. That's way too high for my taste. I won't use it as default.

It's nice to see Quicktime being capable of handling Emese. Still 99% of my collection were perfectly transparent with the old Q127 setting at ~190kbps average. Substantially increasing the bit rate for 99% of my collection just to make 1% transparent eventually doesn't make sense to me.

Maybe they succeed at making the encoder smarter in the future. I think transparency could be maintainable at <=200kbps averages when the encoder is smart enough to scale up high enough, when needed, for samples as Emese.

PS: I think Quicktime X is just the new Player. The new tracks say they were encoded with Quicktime 7.6.3.

Transparency level is unique for each person. In my case Aotuv was transparent on 192 kbit/s for emese sample while rest of encoders weren't.

As per one of the Apple devs:

But those clueless/careless average Joes would have to update their firmware to enable HE-AAC support. You understand that's impossible for that kind of people, don't you?

Second reason why people wouldn't use HE-AAC for iPods is that there is only ~5% people using LC-AAC at low bitrate (=<80-90 kbit/s). Rest of people who use LC-AAC >90 kbit/s won't jump to 64-80 kbit/s. http://www.hydrogenaudio.org/forums/index....showtopic=72265 . If you analyze some numbers around bitrates over internet more than 95% didn't go lower than 128 kbit/s.

HE-AAC is a big NO-GO for music content on DAP. Its application is for low bandwidth.

I'm also wondering what Apple's plans for HE-AAC could be. They usually don't bring out stuff like this just for the cause of it.

Steve Job's next big "one more thing", after he has demonstrated the new "iPad" device, could be something like free 64/96 kbps HE-AAC streaming of the whole iTunes catalog with each one of those. With the usual upgrade option to iTunes Plus quality for $.99 each.

It would be the next logical step. Low quality music is available freely on the internet (legally & illegally), so why not make it also free on iTunes (or a low cost flat-rate) and use it as a comfortable sales channel for high quality tracks including HQ tags & digital artwork?

I can't find now link to news but I read that Apple adopt HE-AAC for radio streams, RSS and maybe postcards.


Apple HE-AAC is only up to 80 kbit/s. Not 96 kbit/s. Averagely at 96 kbit/s HE-AAC isn't better than LC-AAC.

How about finally offering the option to use iTunes to listen to all those internet radio stations streaming in HE-AAC? It is quite annoying having to launch a separate application just to listen to some stations.

I don't know any, are there many?

What do you mean, internet radio stations using HE-AAC? If I had to guess I'd say thousands. Tuner2 is a good start if you want to find them.

One of my favourites is Soma.FM's Secret Agent. I have to start up RealPlayer to listen to it with this link. I would much prefer if I could just use iTunes for it, just as I can for stations that still use MP3 streams (which are often too low-bandwidth for MP3 to sound half-decent). Internet radio stations have a good reason to use as little bandwidth as possible per individual stream which means HE-AAC is a welcome alternative to MP3. Good quality at a considerably lower bitrate.

I know Soma, but they also serve good quality 128kbps MP3. I wouldn't want to trade that for synthesized low bit rate HE-AAC. Are there really many stations you could not receive without HE-AAC support in iTunes?

Kind of off topic, but the original topic is from 2007 and I'd hate to bump it. Where can I find this infamous "Emese" sample?

Someguy21, you can grab the Emese sample over at this thread; Comparing two Nero AAC settings.

i wonder if this time around with iTunes 9 we'll finally put our hands on true vbr on Windows. It would be stupid if they don't.

There are times when it's nice to have the option of a lower-bitrate but still accpetable quality stream -- sharing the office wireless comes immediately to mind.

That is actually something that they can do. However, I think that Apple needs to change the way iTunes operates so that a large message comes up saying "Hey, your iPod's firmware can be updated! Do it!" The firmware update notifications are in small text so they tend to not see them.



No but they could. Still, those people would have to educate themselves on any new features added into iTunes/QuickTime and their iPods, test things out, etc.



I still think that people could benefit from HE-AAC on their iPod shuffle or nano. It could double, triple, or quadruple the amount of songs that their 4-8GB players carry around. Couple that with Apple marketing/word play and they could potentially carry around a bunch of tunes that would be high quality to them.

However, my main benefit of HE-AAC compatibility with iTunes is that I will finally be able to listen to the internet radio channels that I want to. There are a bunch of internet radio channels out there that are broadcast at 32kbps and 48kbps. They are terrible when playing inside of iTunes yet an HE-AAC capable program plays them back just fine (the differences are so bad that I can even ABX them on the cheap speakers in my HP Mini 110XP).

Here is a quality-vs-bitrate graph calculated from some samples. The quality range 0-95 of the new encoder seems to correspond to the range 0-127 of the old encoder.

I continued my tests with the new Q127 mode (~300kbit/s). The most problematic samples I have got: EBU SQUAM, Bibilolo, stuff from Kraftwerk & Tool, and whatnot, all perfectly transparent and not a single remaining problem track!

Can anybody confirm this with his ears? In my opinion the new QT AAC is now the best high bitrate codec available. Even lossyWAV still chokes on some samples.

Is the PTP sample transparent on the new true VBR mode? I found it to be really easy to ABX at iTunes Plus settings.

I found it actually damn hard with the iTunes Plus setting (256kBit VBR constrained, highest quality)! But maybe I'm not focussing onto what you are hearing, what is it and what position/range? Have you tried the same version as the Snow Leopard encoder (Quicktime 7.6.3) for the iTunes Plus encoding?

Give those a try, maybe we have finally both found an encoder that we can unconditionally live with.

Click to view attachmentClick to view attachment

Mainly problems appear at the start with the secend synth drum beat. This sample has artifacts all over the place with LAME V2 - V0 and 320 CBR and fails badly at any other Mp3 encoder.

I tried both samples and managed to ABX the iTunes Plus at 15/17 and faild to ABX the Q127 ATM. Mainly because am not focussing, but the new Quicktime encoder does make a huge improvement on this sample, which can be ABXable at any Mp3 encoder at 320kbps CBR.



Hopefully, so far the reported improvements clearly show that AAC still has plenty to offer. I wonder if Apple will port it to Windows or place it onto iTunes 9, which will be messy for foobar2000 and FLAC users though.

Thank you for your results, /mnt! I share your conclusions that this looks promising for AAC.

If Apple is still going to withhold this from the Windows platform with iTunes 9, it might not take forever until the Nero developers catch up. They have proven their skills time and again. Let's just hope that their employer still allots them enough time for this.

I think audiobooks could benefit from HE-AAC. It seems that the low bitrate of some audiobooks in iTunes is very annoying.

Fcuk the high bitrate, I just replaced my whole AAC collection with the new Q127 encodings! ~300 kbit/s is still about a third of my lossless average and thus the whole package still fits into an iPod classic.

And zero problem tracks (MP3 has 100's, Nero a few) means zero "lossless sorrow" - you know, the feeling, that albeit your ABX verified rationale that a lossy codec is fine for 99% of your material, this one special track might have sounded better, if you had just taken the lossless version with you.

Interesting - I can easily ABX emese at Q127:


Just to make sure we're on the same page, here's the "Tool" string from the m4a file as encoded by XLD and read in foobar2000:


and the "Encoder Quality" setting was at Max. I used fb2k to convert to WAV for the ABX test, but I could easily detect the same artifacts when listening in iTunes under Snow Leopard (and I triple-checked that I had indeed encoded from the original emese.flac, as opposed to re-encoding from an MP3 or some other bonehead thing like that).

HOWEVER, I cannot ABX the Show Me Your Spine sample at just Q90 (I CAN easily ABX LAME 3.98.2 V2), which is not too surprising as I've never been very sensitive to pre-echo artifacts.

Interesting! I think you have just better hearing than me regarding that specific kind of artifact.

What I usually hear with Emese is a quite loud chirping artifact. Nero has it, LAME is terrible, only with the new Q127 it is completely gone.

The artifact I'm hearing is small bursts of a "papery" kind of noise, dead center (i.e. not louder in one channel), and to me QT @ Q90 is actually WORSE than LAME 3.98.2 V2.

FWIW, I'm using Sony MDR-V6 headphones being driven by a Symetrix 304 headphone amp from an M-Audio Transit.

heh, i had somehow gotten it into my head that that was so obviously what it was developed for that it hadn’t occurred to me that anybody would try to use it for anything other than vocal recordings. [...until i started reading this thread, that is.]

I've been testing even further later these days and i just realized that even Q127 for me is not good enough (sounds flat to my ears),compared to Nero AAC q 0,95 for instance. I know Nero may have problems with some samples but i'm sure they will be solved in the next version,but now to my ears i feel more pleased listening to Nero AACs than Apple's ones. Please it's important to note that this is just an opinion of mine,nothing objective like ABX and stuff like that

Without blind testing such statements are meaningless. Sounding "flat" is no kind of artifact, that high bitrate lossy encoders would show, anyway. You can get all kinds of artifacts, but usually not that. Flat sound is a common "result" from non level matched tests.

Just give it a try, you don't need anything else than a full Foobar installation for a perfect ABX setup.

Sounding "flat" and "my ears are more pleased" really don't mean anything when describing an encoder. It is all placebo affect unless you actually conducted blind ABX tests. I imagine that most people would have a really hard time distinguishing QuickTime (at q127) and Nero (at -q0.95) from the source lossless material due to their extremely high bitrates. That is why blind ABX tests are needed in order to make such claims. Otherwise people can go around making all sorts of outrageous claims without any experience or tests.

Okay, most of this is new to me and I'm confused about something...

So now q127 TrueVBR averages 300kbs? I thought, with the previous Quicktime, when using q127 TrueVBR you were basically requesting that the optimum/best (however it should be worded) bitrate be used, no more, no less. So if the new q127 TrueVBR averages 300kbs doesn't that mean Quicktime is forcing an average bitrate instead of using only what is needed?

so itunes 9 + quicktime 7.6.4 has also been released to older version Leopard. I've seen that new true vbr is also on XLD in Leopard now

actually, my assumption is that what rpp3po was referring to was the overall average bitrate of an entire library of audio files... and based on even my own experience, I think it's safe to say that the average bitrates of individual files all but regularly fall around 300kbps (I've seen anywhere in the range of 150-350kbps average bitrates for some of my files during testing at -Q 127).

on a side note, @rpp3po- have you noticed that files with vastly different mixes in each channel (i.e., a majority of albums from the 60's and 70's, many classical albums, etc.) seem to have noticeably larger average bitrates than those with similar mixes in each channel? I've been trying to pinpoint exactly what sounds make the bitrate spike/drop, but so far the most frequent causes for this seem to be the stereo width and/or the difference between mixes in each channel... just thought I'd see if you'd noticed similar behavior with your audio files.

Regarding the ipod + HE-AAC discussion.. What I would like to know is whether those of us who have their library stored in lossless format and convert the songs to a lossy format only for portable players really need higher quality than HE-AAC has to offer. I mean yes the difference is there and it can be heard, but is it possible to distinguish the difference when you are outside on the road or in the gym etc? The only tests I've done so far are in complete silence. But I don't think that I would be able to tell the difference in a noisy enviroment.

I'm not sure but I believe that the HE-AAC format is the best for portable players since you can put more songs in your player and have a quality more or less the same in a noisy enviroment. What do you think?

I can confirm that.


Q127 was indeed intended to provide the optimum/best bitrate for all material. Before the last QT release the developers estimated that this setting, resulting in a whole collection average of about ~190kbit/s, was sufficient. My own testing confirmed this. Still very few tracks remained, that were ABXable, but not necessarily bad. So they included a mode, that vastly scales up the bitrate at the slightest doubt for the paranoid among us. You get the same perceptual quality (transparency!) for ~99% of your collection and <1% less ABXable samples, at the price of 1/3rd more overall bitrate. The old (~190) behavior is still in the code. Just use a lower Q value.



I haven't actually looked at what content causes what bitrate that much. I just went through some of my problematic tracks and evaluated if the new encoder is an improvement. One thing I noticed it that the new Q127 doesn't drop bitrate for classical music as much as other VBR encoders, when it is a high quality recording with content in the complete spectrum. Low quality monoaural tracks from the 50's indeed scale as low as 150 kbit/s (~100kbit/s with the old Q127).



HE-AAC does not target transparency! It just targets to be the better sounding "good enough" encoder for very low bitrates. For transparency >=128 kbit/s LC-AAC is still the much better choice.

Well I think its a weakness to have to use Q127 for codecs supposed to be transparent much lower. Not from a space POV, but from a quality control one. How can one conclude that Q127 is optimal ? AAC is a general purpose codec without specific *transparency* tunings for mid-high bitrates ??. I could be wrong but i think even vorbis is in a similar situation. There are quality settings that produce smaller~higher bitrate in the scale , Yet you don't know at what quality / bitrate a quality-control mechanism kicks in or works well for more difficult material. In that case raising the bitrate doesn't help much and you have to throw bits like crazy. its like saying back in the day that Musepack needed 'braindead' or quality 10 where in fact quality 5 (175 k) had enough control-mechanism for most material and quality 6 (205k) would provide extra safety margin.

When you look at the graph by Nao, the bitrate scales almost linearly. There is no specific point where a "quality control mechanism" would kick in. They just made 'insane' parameters available at the upper end and mapped the new range to the old 0-127 scale. I appreciate this. A lower Q value still gives you the excellently performing and sane ~190kbit/s average known from older versions. The new mode improves freedom of choice for HA nuts, who cannot be satisfied with 99% collection transparency and 1% sounding fine but failing direct A/B comparisons. Just because there is an insane setting available, doesn't mean that a sane ~190 average would be inferior.