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Lossy Audio Compression => Opus => Topic started by: EekWit on 2017-09-13 20:46:14

Title: Point of transparency of Opus 1.2
Post by: EekWit on 2017-09-13 20:46:14
Has anyone done listening tests to find the point where Opus 1.2 becomes transparent to him/her personally? Can this be done using abx?
Title: Re: Point of transparency of Opus 1.2
Post by: halb27 on 2017-09-13 21:09:17
Yes, I've done some ABX listening tests to find out about my point of transparency.
--bitrate 96 is transparent to me for the vast majority of even critical samples. If you ignore these you can go even lower.
There were samples that weren't totally fine using --bitrate 96. With one exception even they were transparent using --bitrate 128.
The exception was a harpsichord sample, harp40_1. Even this is acceptable using --bitrate 140. harpsichord music can be a special problem to other lossy codecs as well, for instance mp3. As long as you aren't much into this genre I would ignore it when it is about struggling for transparency. As you know what are harpsichord music tracks you can use very high bitrate for these.
Title: Re: Point of transparency of Opus 1.2
Post by: EekWit on 2017-09-16 13:06:05
Yes, I've done some ABX listening tests to find out about my point of transparency.
--bitrate 96 is transparent to me for the vast majority of even critical samples. If you ignore these you can go even lower.
There were samples that weren't totally fine using --bitrate 96. With one exception even they were transparent using --bitrate 128.
The exception was a harpsichord sample, harp40_1. Even this is acceptable using --bitrate 140. harpsichord music can be a special problem to other lossy codecs as well, for instance mp3. As long as you aren't much into this genre I would ignore it when it is about struggling for transparency. As you know what are harpsichord music tracks you can use very high bitrate for these.
Thanks for your reply. I actually have a few CDs of harpsichord music in my collection and I had noticed that the FLAC files are unusually large compared to other genres. If you don't mind me asking, do you listen to opus on a portable device? If so what is the device and what player do you use?
Title: Re: Point of transparency of Opus 1.2
Post by: halb27 on 2017-09-16 21:36:26
I am waiting for my favorite Poweramp smartphone music player to support Opus and especially Opus replaygain. Until then I stick with mp3 @ higher bitrate..
I also use a Sansa Clip+ with Rockbox, and I think I can use Opus here right now. But I do want my lossy  music collection to be playable on both devices.
Title: Re: Point of transparency of Opus 1.2
Post by: IgorC on 2017-09-16 22:20:09
Here is Spotify mostly but  I have a several albums on my smartphone  in Opus@128kbps. Didn't notice any failures because I listen mostly rock, metal, alternative music etc... No tonality (like classic music) no problem for Opus.  
Player foobar2000 mobile http://mobile.foobar2000.com/. Everything works great.
Title: Re: Point of transparency of Opus 1.2
Post by: Klimis on 2017-09-17 00:06:51
I am waiting for my favorite Poweramp smartphone music player to support Opus and especially Opus replaygain.
You'll have to wait long for that one. Seems like they have implemented it on dev builds since late 2012 but it is yet to appear on normal builds because devs are sleeping (?). Anyway since Lollipop Android supports natively opus but AFAIK poweramp is not using any of the native decoders and API implementations for sound so you're out of luck.
Title: Re: Point of transparency of Opus 1.2
Post by: halb27 on 2017-09-17 10:24:46
Okay, thanks, I will try foobar mobile and the dev version of poweramp.
Title: Re: Point of transparency of Opus 1.2
Post by: Klimis on 2017-09-17 14:43:29
The dev builds of poweramp are not available to the public. Your only option is Foobar.
Title: Re: Point of transparency of Opus 1.2
Post by: halb27 on 2017-09-17 22:42:10
Okay, so just foobar. Thanks.
Title: Re: Point of transparency of Opus 1.2
Post by: Swug on 2017-09-18 02:06:24
The dev builds of poweramp are not available to the public. Your only option is Foobar.

Opus works on the beta Version 703, you can get it from the Poweramp forum or after signing up for the beta on Google Play here (https://play.google.com/apps/testing/com.maxmpz.audioplayer)
I haven't tested replay gain though and the Bitrate shown if you enable the option seems wrong
Title: Re: Point of transparency of Opus 1.2
Post by: noiselab on 2017-09-18 06:49:15
I was also trying to find safe bitrate for mobile use for Opus. http://wiki.hydrogenaud.io/index.php?title=Opus says 96kbps is "Full bandwidth stereo music, good quality approaching transparency", so I just went with 96kbps just to be safe. I never noticed any artifacts at 80kbps though, though I haven't tried to find any either.

For Android, AIMP also seems to support Opus and ReplayGain. So I've been using both AIMP and Foobar2000 Mobile, since both are efficient and have broad compatibility. Curious to know which is better with battery life though.
Title: Re: Point of transparency of Opus 1.2
Post by: itisljar on 2017-09-18 11:49:01
I tried it and for me it's 80 kbit. I am using opus with my h265 encodes of video material, but not yet for music.
Title: Re: Point of transparency of Opus 1.2
Post by: Funkstar De Luxe on 2017-09-18 13:35:01
I'll be honest, I struggled to ABX at 64kbps. 80kbps is enough for me.

God damn Opus is an amazing codec, I hope it continues to improve - although I have no idea how much further it can be pushed. I remember thinking transparency at 128kbps would be an amazing achievement.
Title: Re: Point of transparency of Opus 1.2
Post by: bstrobl on 2017-09-18 14:39:30
Opus definitely does a great job at 64kbps, hope future encoders become even better at that bitrate to the point where I can simply reencode to that.
80kbps is pretty much my limit as well, can't be bothered listening to killer samples all the time. 96kbps gives a good buffer for nearly all tracks.
Title: Re: Point of transparency of Opus 1.2
Post by: jaybeee on 2017-09-19 20:24:52
God damn Opus is an amazing codec, I hope it continues to improve - although I have no idea how much further it can be pushed. I remember thinking transparency at 128kbps would be an amazing achievement.
isn't it just :-)

I think the biggest thing right now is getting it supported in software and hardware so it can be used more widely. It seems to be the way forward.
Title: Re: Point of transparency of Opus 1.2
Post by: IgorC on 2017-09-19 20:42:10
It's interesting to observe that 4 members have mentioned  Opus@80kbps as point where is hard to spot artifacts for them.
Opus ~80 kbps is roughly equivalent to LAME ~130 kbps (V5)  which lands in an "excellent"  area of quality (MOS 4.5+) http://listening-tests.hydrogenaud.io/sebastian/mp3-128-1/results.htm

So one could say that Opus 80 kbps is "excellent" at least for an average listener.  It's clear that an experienced listeners can spot artifacts at much higher rates.

I never noticed any artifacts at 80kbps though, though I haven't tried to find any either.

I tried it and for me it's 80 kbit.

I'll be honest, I struggled to ABX at 64kbps. 80kbps is enough for me.

80kbps is pretty much my limit as well, can't be bothered listening to killer samples all the time.
Title: Re: Point of transparency of Opus 1.2
Post by: eahm on 2017-09-19 23:31:19
I've been using Opus 1.2.1 @~64 on iOS foobar2000.
Title: Re: Point of transparency of Opus 1.2
Post by: includemeout on 2017-09-21 11:39:06
I think the biggest thing right now is getting it supported in software and hardware so it can be used more widely. It seems to be the way forward.
By the time Opus finally gets widely supported by car stereo manufacturers I'm in.

Though I may turn the tables on my own as soon as I finally upgrade my smart phone to one with external storage support, who knows.
Title: Re: Point of transparency of Opus 1.2
Post by: jaybeee on 2017-09-21 15:43:59
I think the biggest thing right now is getting it supported in software and hardware so it can be used more widely. It seems to be the way forward.
By the time Opus finally gets widely supported by car stereo manufacturers I'm in.

Though I may turn the tables on my own as soon as I finally upgrade my smart phone to one with external storage support, who knows.
funny you mention cars, as I did also type it in my original post before editing it out. Wouldn't that be great to have that support in cars. But I guess with streaming being "the future", then the digital files most people have is still mp3.

I'd like to see car manufacturers simply make the car stereo easily accessible to a variety of media devices; 3.5mm jack, usb connection, maybe allow CD playback still that supports lossy files such as mp3s and opus... hell, even data-DVD support to playback lossy files. The headphone jack and usb support would be easy and I've seen some cars with that in as standard; but not enough.
Title: Re: Point of transparency of Opus 1.2
Post by: Klimis on 2017-09-21 16:45:05
Actually, I believe I said that already in an other post but Chinese car stereos, mostly those cheap ones on ebay have a tendency to support open source codecs. Even though mine didn't advertise that it did, it supports APE, FLAC, OGG and OPUS. If you happen to own one of those I would suggest you to do a test. While on the outside some of them may look identical the internals might differ and they may support more or less codecs than the ones that they advertise.
Title: Re: Point of transparency of Opus 1.2
Post by: includemeout on 2017-09-21 18:36:28
Actually, I believe I said that already in an other post but Chinese car stereos, mostly those cheap ones on ebay have a tendency to support open source codecs. Even though mine didn't advertise that it did, it supports APE, FLAC, OGG and OPUS. If you happen to own one of those I would suggest you to do a test. While on the outside some of them may look identical the internals might differ and they may support more or less codecs than the ones that they advertise.
My case is quite probably hopeless: mine's a Pioneer. ::) 

The only time I saw that sort of behaviour in a branded device, was with a Sony blu-ray player which, though not mentioned on the box, played FLAC files flawlessly - though it required some trickery.
At that time, someone's pointed here on HA that, due to it probably running Android on its firmware, the ffmpeg library was quite probably kicking in when fooled to play the unsupportedlossless format.

Title: Re: Point of transparency of Opus 1.2
Post by: includemeout on 2017-09-21 18:39:01
I'd like to see car manufacturers simply make the car stereo easily accessible to a variety of media devices; 3.5mm jack, usb connection, maybe allow CD playback still that supports lossy files such as mp3s and opus... hell, even data-DVD support to playback lossy files. The headphone jack and usb support would be easy and I've seen some cars with that in as standard; but not enough.
I wouldn't place any bet of most of those media formats you mentioned ever being supported by a single brand new device at this day and age though.
Title: Re: Point of transparency of Opus 1.2
Post by: doom-drone on 2017-09-24 12:56:20
I don't use lossy since my DAP has 400GB of space. But from testing opus when i had a phone with 128gb memory, it was 160kbps with one album needing 448kbps.
Title: Re: Point of transparency of Opus 1.2
Post by: OgGy on 2017-09-25 10:38:36
Did some Foobar2k ABX testing using the "Bachpsichord" and "Applaud" samples:

Bachpsichord sample*
   Opus@64kbps          : Guessing Probability 0.0%
Applaud sample*
   Opus@64kbps, @96kbps : Guessing Probability 0.0%
   Vorbis@112kbps       : Guessing Probability 0.0%
   AAC-LC (fdkaac 0.6.2, libfdk-aac 3.4.12, VBR mode 4) : Guessing Probability 0.0%
  
*Test logs attached.

The artifact heard is noise like "a puff of steam" :
Reducing_noise_due_to_microattacks (http://wiki.hydrogenaud.io/index.php?title=Recommended_Ogg_Vorbis#Reducing_noise_due_to_microattacks)

Is the issue with Block Switching (see link above and below) adressed in Opus or this artifact due to other issues ?
Block Switching Issue (https://hydrogenaud.io/index.php/topic,60956.msg641135.html#msg641135)

I thought FDK AAC @145kbps would do better but the artefact is audibly similar but a bit less pronounced...
Title: Re: Point of transparency of Opus 1.2
Post by: Funkstar De Luxe on 2017-09-25 11:25:08
Actually, I believe I said that already in an other post but Chinese car stereos, mostly those cheap ones on ebay have a tendency to support open source codecs. Even though mine didn't advertise that it did, it supports APE, FLAC, OGG and OPUS. If you happen to own one of those I would suggest you to do a test. While on the outside some of them may look identical the internals might differ and they may support more or less codecs than the ones that they advertise.

I have owned two Chinese headunits (Android 4 + 5), and both were fucking horrendous. Constant issues with both software and hardware. Neither unit was what I would consider cheap, being around the £250 mark. The sounds quality was some of the worst I've eve heard (no, I didn't ABX).

The problem with using a non branded unit as suggested is that you get hardware which (in my opinion) has very little testing, and low test standards. The software is always junk. The reason good manufactures are limited to a small amount of formats is two reasons:

1) They are limited by available chips sets which are automotive grade. The Chinese ones tend just to use phone / tablet innards.
2) They need to limit the amount of support cost for the unit. I'd guess more formats means more customer support calls.

I've now moved to a Sony Apple Car Play unit now, which is of course, super limited in what it supports. But what it does, it does well.

Attached is a picture of the first Chinese unit I had. Looked ok, worked horribly.

Title: Re: Point of transparency of Opus 1.2
Post by: halb27 on 2017-09-25 22:06:59
Did some Foobar2k ABX testing using the "Bachpsichord" and "Applaud" samples:

Bachpsichord sample*
  Opus@64kbps          : Guessing Probability 0.0%
Applaud sample*
  Opus@64kbps, @96kbps : Guessing Probability 0.0%
Well, the more interesting question (at least to me) is: what an Opus bitrate setting does it take to have a) applaud, b) barpsichord being transparent to you.
Title: Re: Point of transparency of Opus 1.2
Post by: Funkstar De Luxe on 2017-09-26 09:59:14
Could someone please point me to where I can download these 'killer' samples? I'd like to try some ABX myself.

Also, OgGy, what made these so easy to identify? Is it pre-echo, hf roll off, something else?
Title: Re: Point of transparency of Opus 1.2
Post by: OgGy on 2017-09-26 10:54:53
You can download them here:
killer samples (http://lame.sourceforge.net/download/samples/)

The artifact is like some high frequency aliasing, steam puff ?

Anyway, as from opus@112kbps it becomes more difficult to ABX the samples, please find the results attached.

Title: Re: Point of transparency of Opus 1.2
Post by: Funkstar De Luxe on 2017-09-26 15:44:22
You can download them here:
killer samples (http://lame.sourceforge.net/download/samples/)

The artifact is like some high frequency aliasing, steam puff ?

Anyway, as from opus@112kbps it becomes more difficult to ABX the samples, please find the results attached.



Thank you!
Title: Re: Point of transparency of Opus 1.2
Post by: halb27 on 2017-09-26 22:01:21
... Anyway, as from opus@112kbps it becomes more difficult to ABX the samples, please find the results attached.
Thank you for testing.
Intereting as you get at 7/8 even @160 kbps with the applaud sample. Would you call the issue negligible at this bitrate? (I'm on holidays ATM and can't try for myself).
Title: Re: Point of transparency of Opus 1.2
Post by: Klimis on 2017-09-26 23:22:02
Actually, I believe I said that already in an other post but Chinese car stereos, mostly those cheap ones on ebay have a tendency to support open source codecs. Even though mine didn't advertise that it did, it supports APE, FLAC, OGG and OPUS. If you happen to own one of those I would suggest you to do a test. While on the outside some of them may look identical the internals might differ and they may support more or less codecs than the ones that they advertise.

I have owned two Chinese headunits (Android 4 + 5), and both were fucking horrendous. Constant issues with both software and hardware. Neither unit was what I would consider cheap, being around the £250 mark. The sounds quality was some of the worst I've eve heard (no, I didn't ABX).

The problem with using a non branded unit as suggested is that you get hardware which (in my opinion) has very little testing, and low test standards. The software is always junk. The reason good manufactures are limited to a small amount of formats is two reasons:

1) They are limited by available chips sets which are automotive grade. The Chinese ones tend just to use phone / tablet innards.
2) They need to limit the amount of support cost for the unit. I'd guess more formats means more customer support calls.

I've now moved to a Sony Apple Car Play unit now, which is of course, super limited in what it supports. But what it does, it does well.

Attached is a picture of the first Chinese unit I had. Looked ok, worked horribly.


These weren't the ones I was referring to. Anything Chinese Android based is terrible. What I was referring was basic 1DIN car stereos that go as much as 20 bucks on Ebay. I got one that actually plays all those formats I mentioned OPUS included, but an identical looking one that a friend of mine got didn't.
Title: Re: Point of transparency of Opus 1.2
Post by: OgGy on 2017-09-27 09:17:46
... Anyway, as from opus@112kbps it becomes more difficult to ABX the samples, please find the results attached.
Thank you for testing.
Intereting as you get at 7/8 even @160 kbps with the applaud sample. Would you call the issue negligible at this bitrate? (I'm on holidays ATM and can't try for myself).


Well @160kbps it is almost negligible but it suprises me how difficult it is to encode.  If I'm not mistaking the Opus Encoder uses only short blocks so that should not be the culprit ?
Title: Re: Point of transparency of Opus 1.2
Post by: includemeout on 2017-09-28 21:57:50
The reason good manufactures are limited to a small amount of formats is two reasons:

1) They are limited by available chips sets which are automotive grade. The Chinese ones tend just to use phone / tablet innards.
2) They need to limit the amount of support cost for the unit. I'd guess more formats means more customer support calls.
Boy! I'd love to know why chip sets manufactures insist on supporting almost-defunct (and, at least over here, unpopular) WMA and not AAC or Vorbis instead.
Title: Re: Point of transparency of Opus 1.2
Post by: Funkstar De Luxe on 2017-09-29 12:47:05
The reason good manufactures are limited to a small amount of formats is two reasons:

1) They are limited by available chips sets which are automotive grade. The Chinese ones tend just to use phone / tablet innards.
2) They need to limit the amount of support cost for the unit. I'd guess more formats means more customer support calls.
Boy! I'd love to know why chip sets manufactures insist on supporting almost-defunct (and, at least over here, unpopular) WMA and not AAC or Vorbis instead.

Because these were likely the prominent formats when the chipset was validated. Besides, no one in the real world knows what Vorbis is. These people are trying to sell mass market products, not appeal out out lying audio nerds like us.
Title: Re: Point of transparency of Opus 1.2
Post by: includemeout on 2017-09-29 23:01:33
Boy! I'd love to know why chip sets manufactures insist on supporting almost-defunct (and, at least over here, unpopular) WMA and not AAC or Vorbis instead.

Because these were likely the prominent formats when the chipset was validated. Besides, no one in the real world knows what Vorbis is. These people are trying to sell mass market products, not appeal out out lying audio nerds like us.
I guess it's something along those lines, and yes, you were right in pointing out Vorbis lack of consumer outreach.

But let us not forget that, outside Windows Media Player, WMA is not that popular either. So I wonder if there's also Microsoft's own doing in keeping such a supersed format alive for so long.
Title: Re: Point of transparency of Opus 1.2
Post by: EekWit on 2017-10-04 09:49:22
How does transparency of opus at 96 kbps compare against vorbis at 112 kbps (nominal bitrate in both cases)? I know this varies from person to person, but I would like to know forum members' opinions on this.
Title: Re: Point of transparency of Opus 1.2
Post by: includemeout on 2017-10-04 10:30:53
How does transparency of opus at 96 kbps compare against vorbis at 112 kbps (nominal bitrate in both cases)? I know this varies from person to person, but I would like to know forum members' opinions on this.
You'll learn with time (the sooner the better, so, in case you haven't yet, you should read this community's TOS (https://hydrogenaud.io/index.php/topic,3974.html) ASAP) that, the very scientific empirical method which HA abides by (unlike the average "feel the force, Luke" audiophile website) will show you that, asking about whether a listening test comparing this or that format has ever been carried out (which, in your case, a simple search will tell you in a jif) - or even better: conducting yourself an ABX listening test - are totally valid under said guidelines - more specifically TOS #8.

Other than that, and hopefully, you'll grow accustomed to the fact that, over here, opinions regarding anyone's perception of quality are utterly worthless (because, let's face it, they're just that), unless properly corroborated by the afore-mentioned tests' results. 

So much so that any answer to that, without said results, would mostly be in direct conflict with TOS 8 - not to mention a contracdition per se, since, as you mentioned yourself: it "varies from person to person".
Title: Re: Point of transparency of Opus 1.2
Post by: EekWit on 2017-10-04 11:34:29
How does transparency of opus at 96 kbps compare against vorbis at 112 kbps (nominal bitrate in both cases)? I know this varies from person to person, but I would like to know forum members' opinions on this.
You'll learn with time (the sooner the better, so, in case you haven't yet, you should read this community's TOS (https://hydrogenaud.io/index.php/topic,3974.html) ASAP) that, the very scientific empirical method which HA abides by (unlike the average "feel the force, Luke" audiophile website) will show you that, asking about whether a listening test comparing this or that format has ever been carried out (which, in your case, a simple search will tell you in a jif) - or even better: conducting yourself an ABX listening test - are totally valid under said guidelines - more specifically TOS #8.

Other than that, and hopefully, you'll grow accustomed to the fact that, over here, opinions regarding anyone's perception of quality are utterly worthless (because, let's face it, they're just that), unless properly corroborated by the afore-mentioned tests' results.

So much so that any answer to that, without said results, would mostly be in direct conflict with TOS 8 - not to mention a contracdition per se, since, as you mentioned yourself: it "varies from person to person".

Hmm. Maybe I asked the wrong question.

What I should have said: "I know this varies from person to person, but I would like to know the results of forum members' personal listening tests."

FYI I checked to see if relevant public listening tests had been carried out and they haven't. This is hardly surprising considering I am asking about a specific pair of codecs at non-identical bit rates.

I could carry out ABX tests of my own and maybe I will. However, I would also be interested to see some kind of a sample of results across different people.
Title: Re: Point of transparency of Opus 1.2
Post by: itisljar on 2017-10-08 07:30:29
I guess you are asking if the point of transparency of Vorbis is 112k for peope who consider Opus transparent at 96 kbit.
I can tell you for me, I'm 42 yrs old, and last time I've tested other codecs (mp3, aac, voris) the point of transparency was at 128k. That was few years ago, and I haven't tested them since, I am happily using them at slightly bigger bitrate (usually VBR which ranges from 100 to 150 k). Two months ago I've tested Opus, and it was seemingly transparent even at 64 k, and as safety net I've been encoding it at 80 k. But I am using it only for recorded movies and tv shows, which have mixed speech and music. For that it's more than perfect... for me :)
Title: Re: Point of transparency of Opus 1.2
Post by: ThaCrip on 2017-10-15 07:55:49
Playing around with some 'QUICK ABX testing' on my PC, which has Klipsch Pro-Media speakers(which are better than average PC speakers for sure(i have had them since the early 2000's)), i started off at 32kbps and then went to 48kbps and then stopped at the 64kbps setting in that, without actually finishing a ABX test, i simply did a QUICK test without spending too much time and it seems once i hit 64kbps i lose confidence in being able to more easily notice the FLAC file vs the Opus 64kbps file by simply clicking back and fourth between Sample A and Sample B to where i can tell it's noticeably more difficult once i hit that point to where i lose confidence in claiming i can quickly spot the FLAC and Opus file without actually completing a ABX test.

so in other words... once i hit the 64kbps setting it's not easy for me to detect artifacts anymore, especially when spending little time without focusing TOO much on things. because as others have mentioned once you start to strain on finding artifacts that's probably a good general guideline of a minimum bit rate you would consider using for general listening to the music straight up to enjoy it. because it appears some people around here can go beyond 128kbps Opus occasionally but i figure at that point you got to be more in that hardcore nitpicking level to where it's almost a non-issue when just straight up enjoying your music if by some chance some minor artifact turns up very briefly on a random song you got as to me it's not worth loading up on excessive bit rate just to 'maybe' clean up that semi-rare artifact that turns up if say the vast majority of music is either transparent or close to transparent to most people at say 96-128kbps range.

so given that info... i suspect ill be very similar to those who mentioned the 80kbps being hard to spot artifacts crowd of people that IgorC mentioned in here. who knows if there would be much of a difference for me if i tested with headphones. even if there is, i can't see myself going all that much higher with the bit rates in Opus especially assuming what was mentioned in this topic that Opus @ 96kbps is 'approaching transparency' is a good ball park figure.

p.s. for whatever it's worth ill be 38 years old later this month.
Title: Re: Point of transparency of Opus 1.2
Post by: francesco on 2018-02-11 08:14:21
hi
may i ask you about your settings?
do you use vbr or cbr
thanks

Title: Re: Point of transparency of Opus 1.2
Post by: IgorC on 2018-02-13 20:18:58
Nowdays there is no reason to go with CBR or ABR (unless for very particular reason like radio streaming with limited network speeds)

VBR is highly preferred for last 10+ years
VBR is both, more bitrate efficient and higher quality (true for any good lossy codec)
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