Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music) (Read 27574 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #25
► Beyond 32 kbps FhG doesn't use Parametric Stereo anymore. For that reason ≥40 Kbps should have a more stereo bitrate-expensive strategy. Stereo image must be better but maybe, I don't know, to the expense of other issues.
From what I can recall, the transition point from Parametric Stereo to Stereo is 48 kbps for the Fraunhofer xHE-AAC encoder. My xHE-AAC Internet Radio streams are 40 kbps and I'm pretty sure they are parametric stereo. They do have perceptually excellent stereo imaging that to my ears is better than HE-AACv2 has ever had so it's possible it isn't parametric stereo.
I'm not surprised that xHE-AAC smoked Opus at low bit-rates. When I tested Opus vs. xHE-AAC my ears found Opus was unlistenable for music below 48 kbps and even at 48 was barely tolerable. I find xHE-AAC to be very listenable at 40 kbps and acceptable at 32 kbps.
I tried EZ CD Audio Converter in Windows 10 arm64 running in Parallels 16.5.0 and it works great! Bought the bundle including the tag editor. Now I can encode xHE-AAC outside of my live radio streams! The 64 bit version works best in my Windows 10 arm64 VM. It's possible Apple will add xHE-AAC encoding with macOS 12 but no guarantee that's happening. For now macOS only has decoding.
Thanks to some very smart friends I now have working web players for xHE-AAC with album art and ID tags! The players work great in Safari in macOS 11.x, iPadOS 14.x and should work in some Android browsers in Android 9 or newer. The players require a browser with MSE enabled which for now rules out iOS (maybe iOS 15 will finally enable it?).
Anyone with a qualifying system outside the US is welcome to try the new players. Sorry but to appease Sound Exchange the players are geo-blocked to USA IP numbers. Here are links to the stations:

CKLG, LG73, Max Radio, New West Rock and Uptown Radio.

Look for the "beta xHE-AAC player" links on each site to launch the new web players. I'm not aware of any other existing fMP4/HLS web players that can do album art and ID tags. These new players are a work in progress but I think they're far enough along in development to make them available here. Any feedback from the golden ears here appreciated!

Cheers,
Phil
Cheers,
Phil

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #26
@imacguru:

According to the last fb2k's decoder made by Kode54, Parametric Stereo is not used beyond 32 kbps CBR:

(tested with 3.5.3 version, EZ CDA Converter 9.3.1)

I'll take a look on those radios (I already tested them last year —it was the only access I had to low bitrate USAC at this time— and I think it was on your recommandations). Thanks for the info!

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #27
Nice test, Guru.

It would be even greater if HE-AACv2 encoder was there (and here is  a very high quality FhG Winamp HEv2 VBR encoder).

Yes, indeed. But I already had 7 pairs in this test. It makes 14 files to listen for each sample and 7 files to mark and to put in order. Adding HE-AACv2 would make 10 pairs. I think it's too much. The risk of ranking errors is also greater: less accurate results. Also add fatigue to the equation.

I see xHE-AAC as the successor to the AAC family (LC-AAC, HE-AAC, HE-AACv2). A bit like OPUS is the successor of VORBIS. The successors are supposed to perform better. I made a duel between those successors and discard the formats they replace.

I'm aware that HE-AACv2 is still highly interesting because it's widely supported (DAP, phones, TV, DVD/BR players, cars…). But as I said, it's too much work. A listening test between xHE-AAC, OPUS and HE-AACv2 at a single bitrate is of course more affordable. I would even discard OPUS from such opposition and let HE-AACv2 vs xHE-AAC fight together in a single duel.


Quote
Speaking of Netflix and low bitrates, an average speed of streaming right now is 3300-3400 kbps. https://ispspeedindex.netflix.net/global.  So xHE-AAC is useful for mobile connections  not so much for an average home wifi connection where Netflix still uses E-AC3 and AAC 128-768 kbps.
Also it's seems like Netflix concentrates more on DRC feature of xHE-AAC https://netflixtechblog.com/optimizing-the-aural-experience-on-android-devices-with-xhe-aac-c27714292a33

Yes it makes sense. My main usage of Netflix is on a tablet and on downloaded files (because streaming uses a lot of the available ressources in my house, and there are other users who needs bandwidth). I believe it's VP9 and image quality is great (outside some artifacts on dark scenes).
If I take as example a recent Netflix grain-free movie (The Devil all the Time—excellent book IMO), the downloaded file is 828 Mb for 138 minutes including two soundtracks. The average bitrate for 1080p is ~800 kbps (video+audio×2+subtitles). In this example, ~30kbps spared on one audio stream makes near 10% size reduction on this HD movie. Not fully negligible!

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #28
Hmm made some comparisons myself and on minimum bitrates xHE-AAC sounds much better indeed, but at 24kbps VBR I begin to prefer Opus...

Opus@24kbps VBR:
+ less pre echo
+ more high freqs
- narrow stereo image

xHE-AAC@24kbps VBR:
+ wide stereo image
- more pre echo
- less high freqs
- annoying short-delay-like artifacts

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #29
Except the encoder in EZ CD Converter is just a newer version of the same encoder in Winamp. But I guess it's pointless to see if anything has improved since then.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #30
kode54,
Do You mean  EZ AAC encoder or USAC one?
Because Winamp encoder was AAC encoder.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #31
Hmm made some comparisons myself and on minimum bitrates xHE-AAC sounds much better indeed, but at 24kbps VBR I begin to prefer Opus...

Opus@24kbps VBR:
+ less pre echo
+ more high freqs
- narrow stereo image

xHE-AAC@24kbps VBR:
+ wide stereo image
- more pre echo
- less high freqs
- annoying short-delay-like artifacts
Tastes and colours… :) Thanks for trying on your side.

But I'm curious: what do you mean by “annoying short-delay-like artifacts”? Could you give me a good sample that illustrate it?

Second question: when you say “less high frequencies” do you hear it? I checked on a graphical tool and xHE-AAC has a constant lowpass at ~17.5…17.8 KHz which seems pretty high and should be transparent for most users. Opus has a 20 KHz lowpass (but also 12 KHz on low energy part like on my sample named “Classical A.10. VA Placido Domingo [37.56.000 +30sec].wav”). I couldn't distinguish both encodings on lowpass (but Opus seems to have some additional noise or a kind of energy boost in trebles: is this kind of brightness you perceive as higher lowpass value?)

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #32
On Opus I have the same impression as you, there is additional noise at very high frequencies, but the differences are due to SBR which has an unfavorable and different ratio from 2:1 in VBR. Try to encode at 48kHz in CBR at 24kbps and you will hear much better because SBR will only be active above 12kHz.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #33
kode54,
Do You mean  EZ AAC encoder or USAC one?
Because Winamp encoder was AAC encoder.
Huh, I did notice that there are different AAC components in EZ CD Converter, but all of the AAC encoders appear to be different versions of the same ~2.5MB library. I guess that's because the LC/HE/HEv2 portion hasn't changed since last December.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #34
Tastes and colours… :) Thanks for trying on your side.
Yeah at these bitrates it comes down to what kind of artifacts are less annoying : ) At very low bitrates Opus has dropouts which to me are quite disqualifying. But they mostly disappear near 20kbps and then it is mostly noisy and monoish which I prefer over pre echo and ringing.

But I'm curious: what do you mean by “annoying short-delay-like artifacts”? Could you give me a good sample that illustrate it?
I attach a sample.
To me it sounds like there's intermixed another copy of some higher frequencies shifted by tens of milliseconds. It probably is a kind of ringing and/or pre echo artifact which in most codecs smears the transients, but here somehow also adds a shifted shadow?

Second question: when you say “less high frequencies” do you hear it? I checked on a graphical tool and xHE-AAC has a constant lowpass at ~17.5…17.8 KHz which seems pretty high and should be transparent for most users. Opus has a 20 KHz lowpass (but also 12 KHz on low energy part like on my sample named “Classical A.10. VA Placido Domingo [37.56.000 +30sec].wav”). I couldn't distinguish both encodings on lowpass (but Opus seems to have some additional noise or a kind of energy boost in trebles: is this kind of brightness you perceive as higher lowpass value?)
Yes, by high frequencies I don't mean barely perceivable high frequencies but rather those in trebles range - thousands of Hz but rather below 10k - they do seem more bright in Opus and I like it over more muffled xHE-AAC.
I haven't checked the graphics yet, just purely what I hear so far...

BTW kode54 I sometimes get console errors on xHE-AAC seeking in fb2k

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #35
Thanks for the sample. I agree that USAC doesn't sound great to me either. I have mixed feelings when I compare it to OPUS. The latter sounds muffled (despite it's high lowpass): I guess it comes from the reduced stereo. It also has audible grain/hiss on transients but in this case it doesn't sound really wrong.

On the other side xhE-AAC provides fresh air with larger stereo image. But on this kind of sample smearing is a real issue. In fact, it's a total mess here. This mess is not fully caused by smearing alone but also by a strange effect I couldn't describe nor explain. Your "shift" explanation makes sense to me and put words on what I hear. There also a metallic sound I dislike.

In this case OPUS sounds less wounded and I could be tempted to give to it a better score.
I checked my test's results: with eig sample (also electronic music) I also gave my preference to OPUS over USAC at 24 kbps.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #36
There also a metallic sound I dislike.
That's exactly what I mean by delay-like artifact. That's how you do cheap metallic/robot voice - apply very short delay effect to it so it sounds like talking in a pot (and that's probably how it was done in early analog era).
Still very impressive performance of xHE-AAC, nice to have a new contender at such low bitrates.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #37
Here is a pack of all 60 samples encoded in both OPUS 12 kbps VBR and Fraunhofer's xHE-AAC CBR 12 kbps. So everyone could take a look on how modern encoders sound at this very small bitrate — compression ratio is 1:117 for RedBook and 1:125 for 48KHz voice samples!).

Thank you very much for posting this. USAC is blowing my mind now - I can't believe what can be done at 12kbps. Genuinely surprised by some of these...

Given the bitrate, I would have said that Opus sounded ok, but my goodness USAC blows it out of the water.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #38
Probably a typo.
It says "CVBR preset 2 98.2 kbps".
Should be preset 3 (?)

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #39
Yes exactly. I can't edit the first post. It's preset 3. Thanks for reporting it.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #40
Yes it makes sense. My main usage of Netflix is on a tablet and on downloaded files (because streaming uses a lot of the available ressources in my house, and there are other users who needs bandwidth). I believe it's VP9 and image quality is great (outside some artifacts on dark scenes).
If I take as example a recent Netflix grain-free movie (The Devil all the Time—excellent book IMO), the downloaded file is 828 Mb for 138 minutes including two soundtracks. The average bitrate for 1080p is ~800 kbps (video+audio×2+subtitles). In this example, ~30kbps spared on one audio stream makes near 10% size reduction on this HD movie. Not fully negligible!
I see.
Anyway I think Netflix, Amazon Prime and others overcompress for mobile streaming.

I've just checked that movie and it streams HEVC 5800 kbps/ LC-AAC, stereo 128kbps on my laptop 1080p/HDR and it goes full 4K at higher rates on a Smart TV.
Yeah, if You are already in the bed and don't want to wake up anybody then mobile ~800 kbps with audio-30kbps is the last resort. But quality of audio/video streams isn't optimal.  :(


Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #41
Quote
At 12 kbps Opus is totally lost on music; it performs significantly better on voice but quality is not truly convincing. The overall result is very poor: sound is muffled, mono-ish, and there is often a bad amount of noise/grain.

That's why I tend to use a bare minimum of 13kbps for Opus (v1.3) when it comes to speech since, at least off the top of my head from my previous playing around with Opus on speech (on my Klipsch Pro-Media speakers, which are above average PC speakers), that any lower than 13kbps, the sound quality starts to decline much more rapidly (i.e. the minimal storage space gains are no longer worth any further decline in sound quality). it seems to clean up the muffled aspect a bit going from 12kbps to 13kbps as I think that's ultimately why I settled on 13kbps as a bare minimum on speech. NOTE: although if one wants to play it a bit safer they could try 16kbps or 24kbps or 32kbps as, off the top of my head, I can't see using any more than 32kbps with Opus for speech as I am of the mindset that I don't need near perfection on speech and would rather go for storage space efficiency.

so, at least in my opinion, don't use Opus any lower than 13kbps for speech as a general rule as I would say it's a good starting point for someone trying to find a really low bit rate to use on their speech encoding. I realize that it's possible, depending on the type of voice, that 13kbps might vary a bit. but still, it's probably not going to be bad enough for me to avoid if I want to store plenty of speech (especially if one is not too fussy on speech quality) and keep the file size minimal.

one last thing... at least based on 13kbps, I can't see Opus for speech only having a slightly higher score than music (i.e. call it roughly 1.4 vs 1.8 which is in the 'annoying' and 'very annoying' section of the 1-5 rating system used around here (although I get the OP used 12kbps and not 13kbps like I am generally referring to)) because of this obvious thing for me... speech is usable, unlike music @ 13kbps (NOTE: although considering the VERY low bit rate, the music could be worse ;) ) ; NOTE: I am not dissing the OP (as I thank the OP for the effort), just making a point is all. and....

...I would say Opus @ 13kbps is no worse than the 'slightly annoying' range on the 1-5 scale (i.e. (5)"Imperceptible", "Perceptible, but not annoying", "Slightly annoying", "Annoying", (1)"Very annoying"). because while you can notice the quality decline vs a higher quality source file, it's not a significant enough of a decline for me to flat out not use it and it's great for keeping passable sound quality speech at a very low file size, especially if you got a lot of speech (say many hours) to store as this greatly increases storage space efficiency.

or another way to put it... I would consider 13kbps to be more Thumbs Up than Thumbs Down for whatever that's worth, although 12kbps and lower I start to shift more to Thumbs Down than Thumbs Up for speech as a general guideline for those seeking to use the lowest possible speech bitrate.

p.s. so I think music, unlike speech, most people would tend to be more picky on obtaining a higher quality for that where as speech as long as it's clear enough and easy enough to understand what's being said, then it's 'good enough'. like I can easily tolerate speech quality that's noticeably lower than 'transparent' than I could with music where a little decline here and there can be okay but if it becomes more obvious I just tend to play it safer with a higher bitrate. for the record... I can easily use Opus @ 64kbps for music as while I can go lower to say 48kbps etc, it's no longer worth the minimal storage space savings for the sound quality hit (I think 64kbps Opus is a safe minimum for music for the common person in my estimations). so I am more of the mindset to use Opus @ 13kbps for speech (minimum) and 64kbps for music (minimum). like I have mentioned before with Opus on music, I think if someone is happy with MP3 @ V5 (130kbps), it's plausible Opus @ 64kbps will be good enough to (even though I was told a while ago that Opus @ 80kbps is more of a equivalent to MP3 @ V5, but I think the average person probably won't notice it even though those around here might etc).
For music I suggest (using Foobar2000)... MP3 (LAME) @ V5 (130kbps). NOTE: using on AGPTEK-U3 as of Mar 18th 2021. I use 'fatsort' (on Linux) so MP3's are listed in proper order on AGPTEK-U3.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #42
one last thing... at least based on 13kbps, I can't see Opus for speech only having a slightly higher score than music (i.e. call it roughly 1.4 vs 1.8 which is in the 'annoying' and 'very annoying' section of the 1-5 rating system used around here (although I get the OP used 12kbps and not 13kbps like I am generally referring to)) because of this obvious thing for me... speech is usable, unlike music @ 13kbps (NOTE: although considering the VERY low bit rate, the music could be worse ;) ) ; NOTE: I am not dissing the OP (as I thank the OP for the effort), just making a point is all. and....

No problem for me. Thanks for sharing your experience.
Let me correct I slight mistake: music was scored at 1.18 and voice/speech at 1.83. The gap is a bit greater than 1.4 vs 1.8.
With some samples I was also tempted to go below 0 for Opus 12 because sound was destroyed. Comments were rare on my logs for this test but here is one:
Example:
Quote
4L File: D:\ABXbitrate\very low bitrate opus vs usac\TEST\Classical D.01. Bach [0.00.000 +30sec].opus12.wav
4L Rating: 1.0
4L Comment: 0, or maybe -1!



...I would say Opus @ 13kbps is no worse than the 'slightly annoying' range on the 1-5 scale (i.e. (5)"Imperceptible", "Perceptible, but not annoying", "Slightly annoying", "Annoying", (1)"Very annoying"). because while you can notice the quality decline vs a higher quality source file, it's not a significant enough of a decline for me to flat out not use it and it's great for keeping passable sound quality speech at a very low file size, especially if you got a lot of speech (say many hours) to store as this greatly increases storage space efficiency.
I don't have any opinion for opus 13 kbps (and you're learning me something by saying that 13 kbps is really different than 12 kbps), but at 24 kbps the voice samples get a much more acceptable score (2,42). It corresponds to a bit more than slightly annoying quality. Opus 24 kbps has sometimes annoying issues (on sibiliant for example). But It was only ranked three time below 2.0: on the korean audiobooks (the only audiobook sample with some music in the background), and on two movies (orchestral music in the background).



Quote
p.s.  like I have mentioned before with Opus on music, I think if someone is happy with MP3 @ V5 (130kbps), it's plausible Opus @ 64kbps will be good enough to (even though I was told a while ago that Opus @ 80kbps is more of a equivalent to MP3 @ V5, but I think the average person probably won't notice it even though those around here might etc).

I made a similar conclusion last year while comparing OPUS/EXHALE at 64 kbps with LAME -V5 as high anchor:
https://hydrogenaud.io/index.php?topic=119333.0

Opus at 64 kbps got an higher score than LAME -V5 with 25 samples from bliiboard charts. But with classical music only Opus 64 kbps results were also far less convincing.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #43
Let me correct I slight mistake: music was scored at 1.18 and voice/speech at 1.83. The gap is a bit greater than 1.4 vs 1.8.

Yeah, my mistake ( so about 1.2 vs 1.8 ). I thought the center line was it when it was the one on the left.

I don't have any opinion for opus 13 kbps (and you're learning me something by saying that 13 kbps is really different than 12 kbps), but at 24 kbps the voice samples get a much more acceptable score (2,42). It corresponds to a bit more than slightly annoying quality. Opus 24 kbps has sometimes annoying issues (on sibiliant for example). But It was only ranked three time below 2.0: on the korean audiobooks (the only audiobook sample with some music in the background), and on two movies (orchestral music in the background).

I am sure my testing is not as thorough as yours since I was doing limited testing on some male voice (English) speech. so it's possible you might not get too much of a improvement had you switched to 13kbps instead of 12kbps as I think the main benefit is the overall speech clarity is improved (i.e. not as muffled). but if other aspects of the weaker sound bother you, then it might still score fairly weak for you etc.

because at least on what speech sound files I was playing around with (male voice (English)), 13kbps is what I consider a bare minimum usable bitrate (although it's possible sometimes I may opt for going to a higher bit rate), even though I obviously agree with you that bumping up bit rates higher is surely a safer bet across a wider range of voice samples since we are not running the bit rates on the edge at that point like we are in the 12-13kbps (and the like) range. but again, it probably boils down to the kind of voice one encodes and opinions vary on what sounds 'good enough' etc.

sure, I have went down to 12kbps before and I can still hear what's being said etc, so it's not like things completely drop of a cliff from 13kbps down to 12kbps on the speech I briefly tested, but there seems to be a bit more clarity in the overall speech sound at 13kbps which is ultimately why I drew the line at 13kbps as a bare minimum for me. NOTE: this is based on my Klipsch Pro-Media PC speakers.

so for you to be generally in the 1-2/5 range for your 12kbps speech testing... I feel, at least on the speech I was hearing at 13kbps, that your 1-2 scores might be a little low (but how we do those rating scales I am sure are going to vary a bit from person to person and it appears your using a wider range of samples to which will probably further lower the overall results vs what I did (but this is not a dis on you as I suspect this is probably expected since I was in a narrower/limited range of testing unlike you)) as if I had to pick a 1 through 5 with 5 being perfect and 1 being horrible, with no in-between scoring, I feel about a 3 sounds right if we want to keep things really simple on that 1 through 5 rating scale without details.

but since you tested 12kbps and to give a brief comment here from memory... on my 12kbps brief test a while ago, while I can't say I would go to a 1/5 score (since things are pretty much totally shot at this point and I am sure I could simply lower bit rate a fair chunk lower from 12kbps to truly get into the 1/5 score range), I might be closer to the 2/5 range at that point of my opinion of 12kbps on speech for Opus.

so we probably ain't far apart from my best guesstimate and, like I was saying, your testing a wider range of sound samples which will probably further lower your overall opinion of 12kbps vs what brief testing I did at 12kbps with male voice (English). so all-in-all, we probably ain't far apart (maybe some, but nothing major).

I might even say this... at least on the speech files I got, while if I went from say 13kbps to 24kbps I would probably get some level of sound quality increase, I am more of the mindset it's not enough of a difference and I would rather nearly split the file size in half by using 13kbps. but again, some might disagree with me and say it's worth the difference for about twice the file size. but like I mentioned before I try to minimize the file size as this way if I store many hours of speech audio, it's barely going to use any storage space. for example... one 2hr50min speech file of Opus @ 13kbps is only 16.6MB.

I made a similar conclusion last year while comparing OPUS/EXHALE at 64 kbps with LAME -V5 as high anchor:
https://hydrogenaud.io/index.php?topic=119333.0

Opus at 64 kbps got an higher score than LAME -V5 with 25 samples from bliiboard charts. But with classical music only Opus 64 kbps results were also far less convincing.

Given your test there it's almost like Opus is better in some ways (but you said Classical might slip up a little though) even though I realize that statistically they are tied. but just looking at the graph, Opus has about 2 samples that are below a certain point (call it about 3.5) where as MP3 has 10 samples. still, I imagine in general day-to-day real world use, both are probably good enough for many people.

also, if I am reading that chart correctly... it seems like Apple AAC @ 64kbps and MP3 @ V5 (130kbps) are statistically tied (but just barely). but personally I would not hesitate in choosing MP3 @ V5(130kbps) over AAC-LC(Apple) @ 64kbps since MP3 seems like the safer all-around choice. or another thing... I suspect ill be able to more easily ABX AAC-LC @ 64kbps than I could MP3 @ V5 (130kbps). not that this is saying much for AAC-LC since 64kbps is really starting to push it (as in straining that format) where as MP3 is still considered good @ V5 for the average person. but I guess that's where all of these a bit more modern encoders come into play in that anything from about 96/128kbps+ it don't matter too much on what you use for the common person. but if you stay around 64kbps and less, then AAC-LC/MP3 starts to fail compared to Opus (and the like).

thanks for the info.
For music I suggest (using Foobar2000)... MP3 (LAME) @ V5 (130kbps). NOTE: using on AGPTEK-U3 as of Mar 18th 2021. I use 'fatsort' (on Linux) so MP3's are listed in proper order on AGPTEK-U3.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #44
NOTE: this is based on my Klipsch Pro-Media PC speakers.

I did my evaluation on headphones (AKG q701 “Quincy Jones”) and laptop jack output. It may explain why I'm more annoyed by some issue.
I couldn't test on speakers: I removed them to please my wife  :-X

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #45
Thanks for doing this test! It got me curious about xHE-AAC and indeed, it works really well in many cases.

However, I can't make it perform better than Opus for mono voice/audiobooks at ~20-30kbps.
To me, Opus at 24k sounds better than xHE-AAC at ~28k, at least with the two clips I tried. The xHE artifacts are quite obvious and unpleasant.

I used exhale 1.1.5 from rarewares and settings 0 and b in foobar (I had to resample to 32kHz to make 0 work).
I'm not too familiar with exhale settings, so maybe I messed something up... anyway, I'm attaching all the samples, source flacs included.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #46
Thanks for doing this test! It got me curious about xHE-AAC and indeed, it works really well in many cases.

However, I can't make it perform better than Opus for mono voice/audiobooks at ~20-30kbps.
To me, Opus at 24k sounds better than xHE-AAC at ~28k, at least with the two clips I tried. The xHE artifacts are quite obvious and unpleasant.

I used exhale 1.1.5 from rarewares and settings 0 and b in foobar (I had to resample to 32kHz to make 0 work).
I'm not too familiar with exhale settings, so maybe I messed something up... anyway, I'm attaching all the samples, source flacs included.

Thanks for your interest :)
I admit that your xHE-AAC encodings don't sound great. Opus is indeed clearer and less distorted.
I joined xHE-AAC encoded with Fraunhofer's encoder. I must be completely tired because I can't get matching loudness  :o
Tell me if it sound better to your ear

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #47
Take a TV commercial that I leave you and try, if you do not feel the distortion and the bands removed, the encoder is not the only problem. However, I'm not happy with the result either, especially for the speech after the tenth and twentieth second.

Wave - xHE-AAC Fh - xHE-AAC Exhale - Opus

In my opinion the minimum bitrate is 36kbps, between 40 and 48kbps for Exhale. Since for xHE-AAC I can control Exhale better from the command line, deciding not to use SBR for example, it is my favorite when I check the quality. Opus is at its worst in the last few seconds.

 

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #48
Tell me if it sound better to your ear

I have listened to your files but in my opinion for the human voice alone xHE-AAC must go down to 32kHz sampling. For Opus it does not matter because nominally it remains at 48kHz, actually removing the content of the last band removes any signal above 15.625Hz and removing the previous one removes everything that exceeds 12kHz leaving you with excellent telephone quality.

Re: A Session In The Abyss: xHE-AAC vs OPUS at 12, 24 and 32 kbps (voice & music)

Reply #49
Take a TV commercial that I leave you and try, if you do not feel the distortion and the bands removed, the encoder is not the only problem. However, I'm not happy with the result either, especially for the speech after the tenth and twentieth second.
Is the USAC file made with Exhale? (I wonder because it's SBR without Parametric Stereo).
I listened to both encodings: OPUS has very agressive sibilants which makes the file hard to listen from beginning to the end (on headphones at least; I tried on my laptop sluggish and pathetic speakers it just sound fine :)) ). Voice is also metallic from time to time with this OPUS 24 kbps encoding.

USAC sounds here much less agressive to my ears but sibilants are not fantastic. From second 10 there's also some additional noise on voice that degrades the clarity. It's not enjoying but I'd say it sounds acceptable (much more than OPUS).