Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

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Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

2021-05-01 17:35:21

Abstract:
Personal blind sound quality comparison of the Opus and the exhale xHE-AAC (USAC) encoders.

Encoders:
The latest versions as of 2021 April were used.
The official build opus-tools-0.2-opus-1.3 was used as the Opus encoder.
The exhale-V1.1.4-cc4151b9_x64 was used as the xHE-AAC (USAC) encoder.
According to the developer, there are no quality change between the 1.1.4 and the exhale 1.1.5.

Opus Settings (~70kbps):
opusenc --bitrate 62 in.wav out.opus

xHE-AAC Settings (~70kbps):
exhale was tested with and without the SBR encoding.
exhale c is the setting with the SBR encoding.
exhale 1 was tested with both the 32kHz and 44.1kHz input.

refalac64 in.wav --rate 32000 -D -b 32 -o in-32kHz.wav
exhale 1 in_32kHz.wav out.32000Hz.nosbr.mp4
exhale 1 in.wav out.44100Hz.nosbr.mp4
exhale c in.wav out.44100Hz.sbr.mp4

Opus Settings (~86kbps):
opusenc --bitrate 80 in.wav out.opus

xHE-AAC Settings (~86kbps):
exhale was tested with and without the SBR encoding.
exhale e is the setting with the SBR encoding.
exhale 2 in.wav out.44100Hz.nosbr.mp4
exhale e in.wav out.44100Hz.sbr.mp4

Sample tracks:
15 sound samples from Kamedo2's samples.
12 sound samples from IgorC's samples.
Total 27 diverse music and speech sound samples.

Hardware:
Sony PSP-3000 + RP-HT560.

Results:

Tracks list:

Conclusions & Observations:

Despite the low bitrates, Opus was rated more than 3.0 on most tracks.
The rate of the exhale was also high, if the best setting was picked.
Using about 16kbps higher bitrate significantly improved the sound quality (p=0.000).
In the ~70kbps exhale settings, converting the input sound into 32kHz before the exhale encoding had better effect on the output quality (p=0.003).
In the ~70kbps exhale settings, using SBR feature may improve the output sound quality, but we cannot be certain from this test alone (p=0.057). Using the 32kHz sampling rate without the SBR feature is more reliable way.
In the ~86kbps exhale settings, using SBR feature may degrade the output sound quality, but we cannot be certain from this test alone (p=0.084).
It is unclear whether opus was the winner, on both ~70kbps settings (p=0.076) and the ~86kbps settings (p=0.111), if the exhale was allowed to change the sampling rate into 32kHz and disable the SBR settings.

Anova analysis:

Code: [Select]

FRIEDMAN version 1.24 (Jan 17, 2002) http://ff123.net/
Blocked ANOVA analysis

Number of listeners: 27
Critical significance:  0.05
Significance of data: 0.00E+000 (highly significant)
---------------------------------------------------------------
ANOVA Table for Randomized Block Designs Using Ratings

Source of         Degrees     Sum of    Mean
variation         of Freedom  squares   Square    F      p

Total              188          38.85
Testers (blocks)    26          13.54
Codecs eval'd        6          10.78    1.80   19.28  0.00E+000
Error              156          14.54    0.09
---------------------------------------------------------------
Fisher's protected LSD for ANOVA:   0.164

Means:

opu80k   xh80k2   xh88ke   opu64k   xh64k3   xh64kc   xh64k1   
  3.92     3.79     3.64     3.57     3.43     3.34     3.18   

---------------------------- p-value Matrix ---------------------------

         xh80k2   xh88ke   opu64k   xh64k3   xh64kc   xh64k1   
opu80k   0.111    0.001*   0.000*   0.000*   0.000*   0.000*   
xh80k2            0.084    0.012*   0.000*   0.000*   0.000*   
xh88ke                     0.424    0.011*   0.000*   0.000*   
opu64k                              0.076    0.005*   0.000*   
xh64k3                                       0.286    0.003*   
xh64kc                                                0.057    
-----------------------------------------------------------------------

opu80k is better than xh88ke, opu64k, xh64k3, xh64kc, xh64k1
xh80k2 is better than opu64k, xh64k3, xh64kc, xh64k1
xh88ke is better than xh64k3, xh64kc, xh64k1
opu64k is better than xh64kc, xh64k1
xh64k3 is better than xh64k1

Raw data:

Code: [Select]

opus.62k	exhale.1_32kHz	exhale.1	exhale.c	opus.80k	exhale.2	exhale.e
%feature	5	 	 	 	SBR enabled	 	 	SBR enabled
%feature	6	48kHz(fixed)	32kHz	44.1kHz	44.1kHz	48kHz(fixed)	44.1kHz	44.1kHz
%feature	7	Opus	xHE-AAC (USAC)	xHE-AAC (USAC)	xHE-AAC (USAC)	Opus	xHE-AAC (USAC)	xHE-AAC (USAC)
%feature	8	≒64kbps	≒64kbps	≒64kbps	≒64kbps	≒80kbps	≒80kbps	≒80kbps
%genre Kamedo2's 15 sample
2.400	3.400	2.800	3.200	3.100	3.800	3.500	
2.900	4.100	3.100	3.300	3.500	3.800	3.200	
3.200	3.400	2.700	3.800	3.900	4.200	3.700	
3.100	3.600	2.900	3.400	3.700	3.900	3.800	
4.200	3.200	2.800	3.100	4.300	3.400	3.800	
3.800	3.600	3.900	2.800	4.100	3.700	2.800	
3.900	3.300	2.900	3.400	3.800	3.500	3.500	
3.500	3.400	3.200	3.300	3.900	3.800	4.100	
2.900	3.500	3.400	3.200	3.600	3.900	3.800	
3.500	3.200	2.600	2.800	3.700	3.600	3.300	
3.500	2.900	2.700	2.800	3.900	3.700	3.100	
3.700	3.500	3.200	3.300	3.800	3.600	3.900	
3.600	3.400	2.900	3.900	4.200	3.700	4.300	
2.900	2.700	2.600	2.700	3.800	3.600	3.300	
3.100	2.800	2.700	2.600	3.700	3.400	3.300	

%genre IgorC's 12 sample
4.100	3.500	3.600	3.100	4.200	3.800	3.200	
4.400	3.100	3.700	3.200	4.200	3.800	3.500	
4.100	3.900	3.500	3.100	4.300	3.800	3.300	
3.400	3.700	3.200	3.800	3.700	4.200	4.100	
3.300	2.900	2.800	2.900	3.900	3.700	3.100	
4.100	3.500	3.600	3.700	4.300	3.900	3.800	
3.800	3.200	2.800	3.600	4.100	3.400	3.700	
3.600	3.400	3.100	3.700	3.600	3.800	3.900	
3.900	3.600	3.900	3.900	4.200	3.700	4.100	
3.200	3.700	3.500	3.400	3.600	3.800	3.900	
4.200	4.100	4.000	4.100	4.300	4.400	4.200	
4.200	3.900	3.700	4.000	4.400	4.300	4.100	

%samples	41_30sec	Perc.
%samples	finalfantasy	Strings
%samples	ATrain	Jazz
%samples	BigYellow	Pops
%samples	FloorEssence	Techno
%samples	macabre	Classic
%samples	mybloodrusts	Guitar
%samples	Quizas	Latin
%samples	VelvetRealm	Techno
%samples	Amefuribana	Pops
%samples	Trust	Gospel
%samples	Waiting	Rock
%samples	Experiencia	Latin
%samples	Heart to Heart	Pops
%samples	Tom's Diner	Acappella

%samples	01 castanets	inst.
%samples	02 fatboy_30sec	Techno
%samples	03 eig	Techno
%samples	04 Bachpsichord	inst.
%samples	05 Enola	Techno
%samples	06 trumpet	inst.
%samples	07 applaud	Live
%samples	08 velvet	perc.
%samples	09 Linchpin	Rock
%samples	10 spill_the_blood	guitar
%samples	11 female_speech	Speech
%samples	12 French_Ad	Speech

Bitrates:

Code: [Select]

opus.62k	exhale.1_32kHz	exhale.1	exhale.c	opus.80k	exhale.2	exhale.e
%bitrate
73541	87569	80218	81199	95249	96833	104028
82934	68322	70776	58106	103687	85669	82409
70562	78701	76656	67404	90624	93945	93430
67597	75989	72969	68502	86942	88539	90542
83964	72871	72271	69271	107602	89230	95502
65405	76979	77163	64635	83760	90984	87770
67762	67039	63194	61219	84811	77129	84183
73479	78271	75570	71365	94913	91817	97155
72357	87082	84782	72109	92233	99839	95125
72197	72303	70099	67653	92551	85964	94803
63895	72056	70826	65889	83000	85863	88973
72916	76197	74314	68295	93070	90621	92831
67815	72736	69377	67638	86549	84703	92090
67855	72474	70436	63394	87487	85528	83817
68512	71395	69441	64523	82994	85566	90219
78994	77419	76047	69405	103220	90768	94019
90460	88465	89677	79211	117074	104521	100253
82867	81995	78370	75990	107081	95468	107020
86735	84614	87039	68243	109700	104426	87674
69926	73064	72773	64572	89108	88835	86566
83625	67835	69040	57987	106781	85543	87132
75347	79339	75534	72506	95983	92273	97080
69710	81516	75998	86717	91347	92649	109027
59436	62915	61911	62957	75877	76115	85728
75511	77804	77281	65768	95042	91216	87071
56687	57407	55188	59437	67418	70100	85110
73034	71268	69321	69985	93052	85483	95719

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #1 – 2021-05-01 19:38:44

Impressive test Kamedo2. Very nice work!

At ~64 kbps I very recently got the same conclusion:

Quote from: guruboolez on 2021-04-27 15:16:38

These results can also be compared to my personal test done last year between 32 KHz and 44 KHz at 64 kbps. 32 KHz was better to my taste. Today, Exhale with SBR probably sound as good if not better (with a plain and full frequency sound due to SBR).

• In other words there's an audible bitrate starvation for exhale at 64 kbps that either resampling to 32 KHz or SBR technique solves (with some drawbacks: preecho and smearing).

• Opus is statistically tied but seems stronger. Sharp attacks samples like castanets.wav or eig.wav help to widen the gap between the two formats.

• It could be noted that exhale c is a bit under 64 kbps. On my big table exhale c is 60.9 kbps while exhale 1 is 64.7 (and Opus -62 should be ~64.5 kbps). So exhale c is both better and smaller than exhale 1 (and is also smaller than 1 resampled to 32 KHz). I wouldn't bother anymore with 32 KHz resampling but rather keep SBRed Exhale at ~64 kbps and below. It could make the encoder a bit more user friendly at least on a GUI side (a bit like EZ CD Audio converter is doing).

80 kbps results are also very interesting.
• SBR seems to show some limitation here and exhale's starvation is clearly less obvious with non-SBR settings (from exhale 1 to 2 : +0.61 point ; from opus 62 to 80: +0.35; exhale -c to -e: +0.30). 80 kbps is clearly a mixed zone for Exhale and it's unclear if SBR is better or not. It can also be a matter of subjective taste.

• Between Exhale and Opus: Exhale -2 gets the highest mark on a sample (4.40) and Opus the lowest one (3.10). On the whole picture Opus performs very well. On my table Opus -80 reaches 83.5 kbps and Exhale -2 79.5 kbps. A score of 3.80…3.90 is quite good, more than acceptable, especially for a trained user like you kamedo2. A good listening experience, with minor issues and a lot of saved space.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #2 – 2021-05-03 07:16:50

@Kamedo2 Excellent work! I was also wondering what is the difference in quality between SBR vs Standard mode. I must admit that I hoped for further improvement when using SBR mode at 80k. Probably not as relevant as it is for 64k or lower.

@Kamedo2 @guruboolez

Is this test at 64k - 80k also relevant when using bluetooth device such as headphones/speakers or is better to use higher bitrate source which is better at transcoding when using bluetooth device? Should 80k be of acceptable quality also for bluetooth?
As I understand, no matter which format/codec is used, transcoding to bluetooth codec always occur.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #3 – 2021-05-03 16:54:36

Quote from: synclagz on 2021-05-03 07:16:50

@Kamedo2 @guruboolez
Is this test at 64k - 80k also relevant when using bluetooth device such as headphones/speakers or is better to use higher bitrate source which is better at transcoding when using bluetooth device? Should 80k be of acceptable quality also for bluetooth?
As I understand, no matter which format/codec is used, transcoding to bluetooth codec always occur.

Common Bluetooth codecs offer very high fidelity. So you can safely ignore the fact that your 80k file will be transcoded to SBC, AAC, or aptX.
However, because the storage is so cheap now, I find no reason to dive into the 80kbps, when I know that the majority of the score will be less than 4.0, unless I am in a desperate effort to save space. Maybe I will use 128kbps (exhale 5, or opusenc --bitrate 128) in your scenario.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #4 – 2021-05-04 08:06:29

@Kamedo2
Thanks for explanation.
Which audio player can play sbc directly?

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #5 – 2021-05-06 23:16:27

Thank You, Kamedo2. Intersting and useful test.

So as of SBR performance in exhale encoder:
48 kbps : SBR is clearly better.
60-64 kbps: Guru prefers SBR, Kamedo2 doesn't. Draw (1:1). SBR and no-SBR are on par.
80 kbps and higher: It's clear that SBR doesn't bring any quality gain. And , in fact, SBR is even inferior in more samples than non-SBR.

TL;DR: Use SBR at 48 kbps, and maybe at 60 kbps if your music isn't full of transients (electronic) and disable SBR at higher bitrates.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #6 – 2021-05-07 00:51:45

Also probably Opus has an advantage over exhale because the former was tested in VBR mode while the second only has CVBR mode.
Opus VBR admits 2x variations for max bitrate (target bitrate 80 kbps, peak 160kbps) while exhale's CVBR, iirc, ~ 1.25x ( maybe somewhat higher with SBR(?) ).

Though CVBR is more suitable for streaming at restricted bandwidth.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #7 – 2021-05-07 09:02:35

So it will be like this.
* Opinion is mixed on this range.

Target bitrate	Best command line	MOS reported by testers
36kbps	exhale a in.wav out.mp4
48kbps	exhale b in.wav out.mp4	3.03, guruboolez
60kbps*	exhale c in.wav out.mp4	3.34, Kamedo2 3.52, guruboolez
64kbps*	refalac64 in.wav --rate 32000 -D -b 32 -o in-32kHz.wav && exhale 1 in-32kHz.wav out.mp4	3.43, Kamedo2 3.05, guruboolez
80kbps	exhale 2 in.wav out.mp4	3.79, Kamedo2
96kbps	exhale 3 in.wav out.mp4	4.15, Kamedo2 4.37, IgorC
112kbps	exhale 4 in.wav out.mp4
128kbps	exhale 5 in.wav out.mp4	4.39, Kamedo2
144kbps	exhale 6 in.wav out.mp4
160kbps	exhale 7 in.wav out.mp4
176kbps	exhale 8 in.wav out.mp4
192kbps	exhale 9 in.wav out.mp4	4.86, IgorC

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #8 – 2021-05-07 18:44:08

Quote from: synclagz on 2021-05-04 08:06:29

@Kamedo2
Thanks for explanation.
Which audio player can play sbc directly?

I don't know of any. foobar2000 v1.6.4 for desktop can't.
SBC isn't really designed for a static storage.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #9 – 2021-05-07 19:20:11

foobar2000 for desktop can play sbc with foo_input_ffmpeg+ffmpeg
Also, any player that can use LAV filters

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #10 – 2021-05-11 20:08:15

Quote from: synclagz on 2021-05-03 07:16:50

@Kamedo2 @guruboolez

Is this test at 64k - 80k also relevant when using bluetooth device such as headphones/speakers or is better to use higher bitrate source which is better at transcoding when using bluetooth device? Should 80k be of acceptable quality also for bluetooth?
As I understand, no matter which format/codec is used, transcoding to bluetooth codec always occur.

During the last two weeks I used my smartphone to stream xHE-AAC stream over bluetooth: on my car, but also on earbuds. I only add xHE-AAC encodings on my phone for pop/rock/metal albums (no classical music so far). And the bitrate was… 24 kbps (twenty four, yes—with Fraunhofer's encoder). I know it sounds totally silly but I was really curious to check how it sounds in real life and not only on ABC/HR tests. More than 400 GB are available on my phone+SD card so I have no space issue.

So how does it sound: If I wouldn't replace my FLAC with xHE-AAC at 24 kbps encodings for archiving purpose I must say that with this kind of music sound quality is really great to my ears, especially while listening in the car. I really had a lot of pleasure while listening these albums. Some constant issues are slightly audible but I quickly forget them (precisely because those issues are constant and not erratic). I caught two or three strong and ugly artifacts—which is a ridiculously small amount at this insane bitrate. Just to give an idea: one hour of music only needs 10 MB. As a consequence 1000 hours of music can be stored in a fraction of a SD card or internal memory (10 GB).

My phone feeds my earbuds over bluetooth with AAC and my car with SBC. I don't think it significantly affects sound quality.

So to answer your question: 80 kbps is more than an "acceptable" basis for BT streaming

NB: as a consequence of this unbelievable experience I've started today a listening test in order to compare OPUS and xHE-AAC at 12, 24 and 32 kbps

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #11 – 2021-05-12 10:32:02

EDIT: I checked this morning what I put on my phone and it wasn't xHE-AAC at 24 kbps (FhG's encoder VBR 0) but at 35 kbps (VBR 1). It's a bit less extreme

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #12 – 2021-05-12 20:25:49

Quote from: guruboolez on 2021-05-11 20:08:15

So to answer your question: 80 kbps is more than an "acceptable" basis for BT streaming

Amazing.

Kudos to all the scientists, mathematicians, and coders who have gotten us to a place where such low bitrates sound so good. It's almost magic. You people are wizards!!

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #13 – 2021-06-07 18:17:24

Quote from: guruboolez on 2021-05-11 20:08:15

During the last two weeks I used my smartphone to stream xHE-AAC stream over bluetooth: on my car, but also on earbuds. I only add xHE-AAC encodings on my phone for pop/rock/metal albums (no classical music so far). And the bitrate was… 24 kbps (twenty four, yes—with Fraunhofer's encoder). I know it sounds totally silly but I was really curious to check how it sounds in real life and not only on ABC/HR tests. More than 400 GB are available on my phone+SD card so I have no space issue.

So how does it sound: If I wouldn't replace my FLAC with xHE-AAC at 24 kbps encodings for archiving purpose I must say that with this kind of music sound quality is really great to my ears, especially while listening in the car. I really had a lot of pleasure while listening these albums. Some constant issues are slightly audible but I quickly forget them (precisely because those issues are constant and not erratic). I caught two or three strong and ugly artifacts—which is a ridiculously small amount at this insane bitrate. Just to give an idea: one hour of music only needs 10 MB. As a consequence 1000 hours of music can be stored in a fraction of a SD card or internal memory (10 GB).

My phone feeds my earbuds over bluetooth with AAC and my car with SBC. I don't think it significantly affects sound quality.

NB: as a consequence of this unbelievable experience I've started today a listening test in order to compare OPUS and xHE-AAC at 12, 24 and 32 kbps

Given your post here... I played around with a few music tracks a moment ago with the FhG(Winamp) encoder through Foobar2000 at 24kbps and I got to say I pretty much agree with you as it's usable (and impressive given the really low bit rate!) as I can't say I notice any really obvious flaws on the overall sound on the brief test just sitting back and listening on my Klipsch Pro-Media speakers.

doing the same with Opus @ 24kbps I can tell FhG @ 24kbps is clearly superior at these bit rates, at least based on a rock song and some others I briefly tested. although Opus encodes much faster than FhG, about 20-25x for FhG and about 80-85x for Opus on my i5-3550 using Foobar2000 under WINE on Linux Mint v20.1-Cinnamon. NOTE: I wonder how that effects smart phone battery life as I would assume Opus is more CPU efficient. because if using FhG has a noticeable effect in battery life being shortened ill probably just stick to Opus at 64kbps. but if FhG is about the same or not much worse, then it's possible Ill seriously consider using it, especially on certain music etc.

also, at least on the song I was testing (a rock song) briefly to ball park things... FhG @ 24kbps (the songs is 24kbps since it's CBR) seems roughly comparable to Opus @ 40/48kbps (the songs bitrate here is 42/50kbps) as when I tried Opus @ 24kbps/32kbps, I definitely prefer FhG over those as the overall sound is more stable and not as easy to notice as it's only once I bumped the Opus file to 40/48kbps it cleaned up the more obvious stuff and seemed similar to FhG @ 24kbps. but generally speaking... I avoid Opus any lower than 64kbps as while 40kbps/48kbps ain't too bad, I would rather spend the extra bitrate to clean up the sound a bit to be on the safer side and 64kbps is still pretty low on file size already.

I tried going to 16kbps with FhG, but there is too much of a sound quality hit at this point. although considering it's only 16kbps, it's impressive. so, at least based on the preset options with FhG in Foobar2000, 24kbps is the bare minimum for music in my opinion.

so at this point... ill probably encode a fair amount of my music to FhG @ 24kbps to try listening to on-the-go for smart phone use (with Foobar2000 mobile version) just to see how it sounds when just listening to it in real world situations like you did. currently I have been using Opus @ 64kbps in recent memory on a smart phone.

so at least for me and based on some quick testing with Opus... for those trying to go for as minimal file size as possible without effecting sound quality TOO much, I think 40kbps or 48kbps is a bare minimum (assuming we are testing by 8kbps increments (i.e. 24kbps/32kbps/40kbps/48kbps etc)). but like I say, I tend to personally go with 64kbps minimum as at 48kbps, only 16kbps more (i.e. 64kbps) and should give a decent all-around boost to sound quality across a wider range of music as I figure going any higher than 64kbps, one is best off going straight to 96kbps and forget about it as the quality is more than high enough at 96kbps on Opus.

with all of that said... I figure if I am going to use something besides Opus @ 64kbps on a smart phone for example, I would probably at least want to split the bit rate in half (or get a decent bump up in sound quality at same bit rate) to consider something else and in this regard FhG @ 24kbps is solid storage space savings, especially if someone has a lot of songs to store and are using a typical smart phone that might only have something around 8-16GB of internal storage which it seems many of the more budget smart phones are in that ball park.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #14 – 2021-06-07 20:21:36

Quote from: ThaCrip on 2021-06-07 18:17:24

Given your post here... I played around with a few music tracks a moment ago with the FhG(Winamp) encoder through Foobar2000 at 24kbps and I got to say I pretty much agree with you as it's usable (and impressive given the really low bit rate!)

Thanks for sharing your feelings

Just to clarify: you are talking about HE-AACv2 at 24 kbps (with Fraunhofer's encoder included in Winamp), right? And just to be sure, you know it's not the same as xHE-AAC, which is a different format (and probably a better one than HE-AACv2 at this bitrate)?

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #15 – 2021-06-08 07:43:45

Quote from: guruboolez on 2021-06-07 20:21:36

Quote from: ThaCrip on 2021-06-07 18:17:24
Given your post here... I played around with a few music tracks a moment ago with the FhG(Winamp) encoder through Foobar2000 at 24kbps and I got to say I pretty much agree with you as it's usable (and impressive given the really low bit rate!)
Thanks for sharing your feelings
Just to clarify: you are talking about HE-AACv2 at 24 kbps (with Fraunhofer's encoder included in Winamp), right? And just to be sure, you know it's not the same as xHE-AAC, which is a different format (and probably a better one than HE-AACv2 at this bitrate)?

Yes, your right.

but I incorrectly assumed you were referring to HE-AACv2 given you mentioned 24kbps etc since from what I can see in Foobar2000, the lowest selectable bit rate on Exhale (using exhale-V1.1.6-b11042a0) is 48kbps with the 'xHE-AAC with SBR' option as just the standard 'xHE-AAC' bottoms out at 64kbps.

so I would imagine if it's possible to go lower than 48kbps, one probably needs to use that 'custom' option somehow?

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #16 – 2021-06-08 12:06:19

Exhale is a different xhe-aac encoder. It doesn't go below 38...40 kbps on 2CH/44100Hz.

Fraunhofer's encoder has more options, and allow much lower bitrate. It's this encoder I've tested

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #17 – 2021-06-08 13:04:18

Quote from: guruboolez on 2021-06-08 12:06:19

Exhale is a different xhe-aac encoder. It doesn't go below 38...40 kbps on 2CH/44100Hz.

Fraunhofer's encoder has more options, and allow much lower bitrate. It's this encoder I've tested

I assume the Fraunhofer encoder is not usable with Foobar2000?

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #18 – 2021-06-08 14:18:20

Quote from: ThaCrip on 2021-06-08 13:04:18

I assume the Fraunhofer encoder is not usable with Foobar2000?

No, it doesn't work outside EZ CDA Converter (commercial, but 14 days free trial if you want to test it)

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #19 – 2021-06-08 19:14:22

Quote from: guruboolez on 2021-06-08 14:18:20

Quote from: ThaCrip on 2021-06-08 13:04:18
I assume the Fraunhofer encoder is not usable with Foobar2000?
No, it doesn't work outside EZ CDA Converter (commercial, but 14 days free trial if you want to test it)

Looks like ill be sticking with Foobar2000 for now (even if I wanted to use it, I would have to load it in a Windows VM on my Linux machine since apparently that won't work on WINE). thanks for the info though.

on a side note, with Foobar2000... I was playing around with HE-AACv2 on Apple and it's a bit weird compared to FhG as FhG seems to work more like what it says at those really low bit rates. because on Apple I try using 24kbps or 32kbps and the actual bit rate of the file is always about 32kbps and that's with CVBR or CBR or ABR modes on Apple. but I can say the Apple encoding at these lower bit rates is clearly faster than the FhG, but at least FhG is bitrate accurate unlike Apple as FhG actually works when I set it to a specific bit rate, like 24kbps CBR for example FhG is truly that where as Apple is pretty much 32kbps even when I select 24kbps. but on Apple vs FhG when setting Apple to 32kbps CVBR the output file was 33kbps where as the FhG VBR1 on the same music file (FLAC source of course) is 36kbps. plus, I noticed that FhG files are 'SBR+PS' where as Apple has just 'SBR'. but I guess the bottom line is... if I want anything under 32kbps I have to use FhG.

Re: Personal Blind Listening Test of Opus and the exhale xHE-AAC encoder

Reply #20 – 2021-06-09 11:30:04

Quote from: guruboolez on 2021-05-11 20:08:15

So to answer your question: 80 kbps is more than an "acceptable" basis for BT streaming

I didn't saw this earlier.

Excellent news. That means that SBC is very "neutral" in transcoding and probably wont introduce new / strong artifacts.

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