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MQA Deep Dive - I published music on tidal to test MQA

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GoldenOne

GoldenOne

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Thread Starter #21
Fair point re DSD being open source, though I still don't believe it serves a purpose in playback, its intended as a recording medium

Not saying MQA aren't a bit shifty, what company that is trying to sell something isn't.
Yeah, I agree with you regarding DSD and personally have not found many situations where there was a DSD version that was definitively better than available PCM ones. (Usually if this was the case it was also because the DSD version was a different master).
However it is sometimes a useful tool to get better output from a mediocre dac as the oversampling and modulation from some dedicated software tools are better than the ones in some lower end dacs.

But my view is that DSD isn't being pushed upon us, doesn't cost anything, and I can still obtain HiRes PCM/DXD of the content instead of DSD if I wanted.
With MQA none of those are true. Its costly, and I cannot use native HiRes as an alternative. (Its aggressive expansion to encompass even 16/44.1khz content is also beyond frustrating)

The diff between 11-13khz is interesting, but still not conclusive. You don't know which is "correct", just that there is a diff, what if you 44.1 file was downsamples with an algorithm that caused this? Or the fact that the MQA file started with a different bitrate master?
Also potentially true, but again the fact that we cannot test ourselves by producing an MQA version of a file to compare, nor fully unfold one without having to record in the analog domain (immediately making things more tricky and adding a LOT of variables) makes it difficult.
I'll have a look at the 2lno files and repeat some of the same tests on those later. I remember coming across it previously but if I remember correctly there was something different about those files compared to other available ones. I'll double check though cause I can't remember what the issue was.


As for software that an do the unfolding:

https://code.videolan.org/mansr/mqa/

Although last time I looked, only the first unfold worked correctly, the second unfold produced garbage.
I'm recording the first unfold from Roon's output as roon is certified by MQA themselves and widely used (could also in theory use the tidal player itself but I don't have it installed and wanted to use the same player for local files for sake of consistency).

The second unfold is a bit tricky, because its only done on hardware. This seems to be an arbitrary restriction and i'm sure there is likely someone clever who may be able to reverse engineer or modify a product such as this MQA addon card: https://www.sonnet-audio.com/Accessories.html , in order to obtain a digital, fully unfolded copy.

You could record the analog output of an MQA dac, but then its tricky to find a situation where you can get a fair test, as even in devices which are using the same DAC, such as the D90 and D90 MQA, other components on the digital input side differ. And most MQA dacs don't have an option to force them NOT to unfold MQA. So you cannot record the analog output of a non-unfolded MQA file from that dac as it will always unfold it.


My predicament is that in Canada there are no alternative hi-res streaming services so I've got to learn to deal with MQA for now. My hope is that eventually they go out of business and it becomes public domain and or eventually the'll be a more fleshed out version of mansr's code and we can all just use MQA without a special dac.
Yeah hopefully it becomes more prevalent. I imagine spotify announcing their lossless tier will mean a LOT of people will join or switch to that.
 

nimar

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#23
The second unfold is a bit tricky, because its only done on hardware. This seems to be an arbitrary restriction and i'm sure there is likely someone clever who may be able to reverse engineer or modify a product such as this MQA addon card: https://www.sonnet-audio.com/Accessories.html , in order to obtain a digital, fully unfolded copy.
Thats just what mansr had done, using a linked lib from the bluos firmware IIRC. There's no technical reason the last unfold has to be done in hardware, that is something that MQA is untruthful about. There aren't any analogue circuits converting MQA, its just software running inside your DAC, and as such it can run outside of your DAC. What might be true is that they decide what filtering to use based on the hardware but I find that somewhat unlikely.

Re recording analogue output, I was thinking along the lines of using the same DAC, eg. D90 MQA you mention, and comparing unfolded file MQA 24/88 file vs the same PCM 24/88. Though as already stated even this isn't conclusive.
 

mansr

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#25
As for software that can do the unfolding:

https://code.videolan.org/mansr/mqa/

Although last time I looked, only the first unfold worked correctly, the second unfold produced garbage.
It works for "rendering" to 176.4/192 kHz but not higher rates. I still haven't looked into why it's failing. Older versions of the Bluesound library work correctly.
 
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#26
I did subscribe to Tidal's high fidelity service with MQA for a period of time. I have an Asus SMF computer in my stereo setup. I purchased a new DAC that supported MQA. The setup did not work reliably and I suspect the DAC was the problem. The decoding was partly done in the TIDAL player and partly in the DAC. I won't specify the name of the DAC because I only have a suspicion that was the issue and the product comes with great reviews otherwise.
I was able to get full credit for the DAC and went back to normal streaming fidelity using my Audioengine D1, which has worked like a charm for several years providing acceptable quality. I still believe discs, especially SACD and Bluray Audio are the way to go for the best in sound fidelity. But being able to stream almost any album ever recorded at any time does have an irresistible charm. I stream about 10-20% of my listening time.
Suffice to say I won't try higher bit rate streaming any time soon.
 
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GoMrPickles

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#27
Do we need another MQA thread? The effort they put into preventing any verification of any of their claims should be enough reason to just ignore them. When supposed engineers lie to customers they get fired.
I think it's nice to have short threads that summarize things. The post you linked to was ~6000 words, excluding footnotes. It's great to have brief (this) and highly detailed (that) content, for different audiences. Frankly, if you're wondering, "Should I get an MQA DAC?", this post is as informative as the other, much longer post.

Of course this thread is apparently about DSD now so who cares.
 

Lsc

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#28
Qobuz - sound quality may be better but for whatever reason the songs seem too “fast”. And the interface is too fat for my older laptop and not that it’s not intuitive but dreading creating playlists again.

So going back to Tidal. Whether MQA is crap or not, Tidal sounds better than Amazon music to be and just a shade behind Qobuz.
 
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#29
With the frustrating addition that if you are a Tidal user, even if you have no MQA dac, and use the "Hifi" streaming quality setting, MQA encoded/lossy files will still be served to you.
Would you please clarify this? If I understand correctly you are saying that, without an MQA DAC, if you play a "Master" release with Streaming Audio Quality set to HiFi (or are playing through the browser interface that does not support Master quality) then you will be served the MQA and not the 16/44 FLAC?

It's not clear how this is demonstrated by your experiments. I am under the impression (please correct me if I'm wrong) that a standard 16/44 FLAC is served with the HiFi quality setting, even if the release is a "Master" release.

Also, FWIW I think it's important to note that your experiment uses a 16 bit MQA file, so it's no surprise that it's inferior to Redbook without at DAC.
 
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GoldenOne

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Thread Starter #31
Would you please clarify this? If I understand correctly you are saying that, without an MQA DAC, if you play a "Master" release with Streaming Audio Quality set to HiFi (or are playing through the browser interface that does not support Master quality) then you will be served the MQA and not the 16/44 FLAC?

It's not clear how this is demonstrated by your experiments. I am under the impression (please correct me if I'm wrong) that a standard 16/44 FLAC is served with the HiFi quality setting, even if the release is a "Master" release.

Also, FWIW I think it's important to note that your experiment uses a 16 bit MQA file, so it's no surprise that it's inferior to Redbook without at DAC.
On tidal an album/track can often have two releases. One labelled as "Master" and one without. Sometimes there is only one, sometimes not.
If the track is labelled as "Master" in the tidal UI, then regardless of your streaming setting, you will receive the MQA encoded file, at least in this instance (which means its likely not the only one).
1617113878931.png

MQA is 44/16 FLAC, its not a new format, they just claim that they have encoded and can "unfold" extra information from it. How they are doing this they've not given any information on. And given as so far there has yet to be a test done by anyone showing that to be remotely true, it seems likely the answer is that its actually nonsense.
(More than happy to be proven wrong, it'd be VERY easy for MQA to do so, but the fact that they have not, and moreso that they go to such lengths to make it difficult to test yourself suggest that they can't)

I'm not quite sure what you meant by the last statement but yeah, MQA is 16 bit, and gets "unfolded" to 24 bit.
1617114117325.png
 
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#32
The only good thing about MQA is that the MQA releases from Universal Music (Master on Tidal) don't have watermark that existed on lossless/HiRes from other service. But Universal Music seems suspend the watermark action for new releases after 2015-2016 (2015 for DG, 2016 for Decca), so MQA has lost their only genuine advantage now.
 

dmac6419

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#34
I figured that given how aggressively Tidal has been expanding their use/incorporation of MQA, and there seems to be an awful lot of debate about whether or not MQA is good or lives up to the claims, and not much testing going on, (including lack of evidence from MQA themselves), I should try to remedy that.

TLDR: MQA isn't lossless, is arguably worse than normal flac, and is seemingly nothing more than a (quite effective) scheme to generate licensing fees. With the frustrating addition that if you are a Tidal user, even if you have no MQA dac, and use the "Hifi" streaming quality setting, MQA encoded/lossy files will still be served to you. And the only way to avoid that being to switch to Qobuz


This post is intended to answer test and answer a few questions about MQA, namely:

1) Are MQA releases the same master as non-MQA?

2) If you don't have an MQA dac, is standard FLAC and MQA-FLAC the same / does MQA provide a benefit even on a normal dac?

3) Is unfolded MQA lossless or as good as native HiRes?



This is normally quite tricky to test because MQA ensures that there are no native HiRes releases for tracks that are released in MQA on tidal. So you cannot directly compare them. However, there are a couple which seem to have slipped by.

Absofacto's "Thousand Peaces" for example has ONE of the songs in 96khz on qobuz (the rest are 44.1) and 88.2khz via MQA on tidal. I initially tested this, however it turned out that the Qobuz redbook and tidal redbook versions were different, meaning they are using different masters and could not be directly compared.

Answer 1: MQA/Masters SOMETIMES uses a different master source. Meaning the file formats themselves cannot be compared as the information itself is different. This is likely done to give the impression of sounding better even though it's nothing to do with the file format.



So then, we need a different test track/album. Sam Smith's "The thrill of it all" however was ideal. It has a native 24 bit 88.2khz version on qobuz as well as the standard 44.1khz release. And on tidal there is also a 44.1khz release and can be 'unfolded' to 88.2khz via MQA. Meaning we can compare identical sample rates.

The first thing to do was to check whether the Tidal and Qobuz redbook/non-MQA files were actually the same. ie: Are tidal and qobuz using the same master for the song. To do this I downloaded the Redbook 16 bit 44.1khz version from Qobuz, and then the same from the release on tidal that was not marked "Master".

Deltawave showed that these two files were 100% absolutely bit for bit identical. So we can conclude that Tidal and Qobuz are using the same master for the song. Perfect.

View attachment 120198

Next, I downloaded the "Master"/MQA release, but without any MQA unfolding. ie: keeping it as a non-MQA dac owner would be playing it. Both these files are 44.1khz, but are not the same. In fact they are only 0.43% bitperfect with a 40dB null (24 bit accuracy is 146dB) We can see that the master is clearly the same as the majority of the track is identical, but the MQA version has a significant amount of high frequency noise compared to the lossless FLAC.



(Y axis is frequency, X axis is time. Green means that part is the same, purple/red means it is higher or lower in level and different from the original)

Answer 2: If you do not have an MQA DAC, MQA should be avoided, the content is NOT the same as the lossless original, and has more high frequency noise.


So then, now we need to see what happens if you unfold the MQA version to 88.2khz and compare it with the native 88.2khz version. I did this by using Roon, which has MQA decoding support, and recording bitperfect output, then comparing against the native hires 88.2khz version from qobuz.

Now things are really quite messy. The unfolded version differs significantly from the native hires, with again a lot more high frequency noise, as well as a band from about 11.5khz to 13.5khz where content differs a concerning amount in this specific instance.



Therefore

Answer 3: No, MQA is NOT lossless (a claim which MQA has recently removed from their marketing material), and even when unfolded does not match native HiRes content. I would love to test a full decoder/renderer, but MQA does not allow any "Full Unfolding" device to have a digital output. (Gee I wonder why that is, it'd sure be a shame if someone were to so easily be able to record and disprove the marketing claims.)

Additional arguments:

  • MQA is actually probably worse than native playback. MQA makes it basically impossible to obtain a "normal" and MQA version of the same hires file. BUT, Stereophile did manage to convince them to send an MQA encoded single-impulse file. Their testing showed three things:
    1 - Playing back an MQA encoded file on a non-MQA dac caused issues, and created an asymmetric impulse response.
    2 - Playing it back on an MQA capable dac, it was minimum phase, not linear.
    3 - Playing back a NORMAL, non-MQA encoded impulse response file, with the MQA filter turned on on the DAC, produced an IDENTICAL result to the MQA file, suggesting that MQA is nothing more than a basic minimum-phase upsampling filter in this situation, and absolutely nothing to do with the source file. https://www.stereophile.com/content/mqa-tested-part-1
    There is significant evidence from multiple third party sources to show that MQA has all sorts of problems. http://archimago.blogspot.com/2018/02/musingsmeasurements-on-blurring-and-why.html


  • MQA incurs an additional cost to you. You are paying for the licensing fees that are tacked on to products to get MQA support, and at every other step in the process. A good post from the manufacturer Linn is available here: https://www.linn.co.uk/blog/mqa-is-bad-for-music Given as we have now demonstrated that MQA is NOT a substitute for native HiRes content, its hard to argue that MQA is doing much more than charging you for a sub-par version of something you already had (native hires music). If you want the best quality, demand native hires releases, not licensed, closed-source, proprietary compression. Schiit audio has also spoken on it: https://www.schiit.com/news/news/why-we-wont-be-supporting-mqa


  • MQA IS NOT sourced from a HiRes master. Even if you are happy with it not being lossless, it is not actually even compressed from a HiRes source. Neil Young removed his music from tidal when after providing 44.1khz masters, Tidal suddenly released MQA versions, which would have been created simply by altering/upsampling the original. He did NOT provide them with HiRes masters to release in MQA, and you can read about this here: https://neilyoungarchives.com/news/1/article?id=Tidal-Misleading-Listeners
    "Tidal's master is a degredation of the original to make it fit in a box that collects royalties. That money ultimately is paid by listeners, I am not behind it. I am out of there. Gone. My masters are the original."
    MQA is at least in some situations simply an upsampled version with a licensing fee slapped on.....


  • There is ZERO proof of any of MQA's claims. There is absolutely zero evidence to support any of their marketing, claims that they can fit 24 bit 192khz content into a 16 bit 44.1khz file, and in fact, all objective evidence and testing so far (including this post) conclude that MQA's claims don't make sense at all. The claims they make would be VERY easy to demonstrate and prove if they were true....
    Most MQA content cannot be obtained in native HiRes anywhere. And they do not allow any "full unfolding" device to have a digital output to prevent anyone from recording or testing the result.


Thanks for reading, hopefully this helped some people!
What are your technical,professional qualifications are you an engineer of some sort or just a listener?
 

abdo123

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#35
@GoldenOne

The files you used in your tests, were they 24-bit MQA (~16 bit PCM, ~8 bits encoded) or the 16-bit 'MQA CD' (13 bits PCM, 3 bits encoded)?

your latest comment confused me.

just because the initial track before MQA encoding was 44.1/16 doesn't mean that the FLAC container after encoding is also 16 bits.

Could you explain what this means?
you will probably find the answer in my comment above. MQA CD is lossy in the bits that matter.
 

mansr

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#36
The files you used in your tests, were they 24-bit MQA (~16 bit PCM, ~8 bits encoded) or the 16-bit 'MQA CD' (13 bits PCM, 3 bits encoded)?
Where does this idea about the bit allocation come from? It is wrong. Starting from the top, the vast majority of MQA files look like this:
  • ~13 bits meaningful PCM data
  • ~2 bits (shaped) dither noise
  • 1 bit MQA metadata + some data
  • 8 bits MQA data, not present in 16-bit files, ignored if missing/damaged
The split between PCM/dither and MQA is not fixed, though. The non-MQA part can occupy anything from 8 to 15 of the top bits regardless of the container size. If fewer than 15 bits are used for PCM, the lowest bits in a 24-bit container are unused.

A large number (50% or so) of the MQA streams on Tidal are made from 44.1 kHz masters. The are still delivered as 24-bit MQA. The only conceivable purpose of using MQA for these is obviously to obfuscate. A plain FLAC from a 44.1/24 master is smaller than MQA of the same.
 

abdo123

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#37
Where does this idea about the bit allocation come from? It is wrong. Starting from the top, the vast majority of MQA files look like this:
  • ~13 bits meaningful PCM data
  • ~2 bits (shaped) dither noise
  • 1 bit MQA metadata + some data
  • 8 bits MQA data, not present in 16-bit files, ignored if missing/damaged
The split between PCM/dither and MQA is not fixed, though. The non-MQA part can occupy anything from 8 to 15 of the top bits regardless of the container size. If fewer than 15 bits are used for PCM, the lowest bits in a 24-bit container are unused.

A large number (50% or so) of the MQA streams on Tidal are made from 44.1 kHz masters. The are still delivered as 24-bit MQA. The only conceivable purpose of using MQA for these is obviously to obfuscate. A plain FLAC from a 44.1/24 master is smaller than MQA of the same.
after the decode, how many bits of PCM do you end up with?
 
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GoldenOne

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Thread Starter #38
What are your technical,professional qualifications are you an engineer of some sort or just a listener?
I don't have professional engineering qualifications. But you don't need a degree for this kind of testing.
@GoldenOne

The files you used in your tests, were they 24-bit MQA (~16 bit PCM, ~8 bits encoded) or the 16-bit 'MQA CD' (13 bits PCM, 3 bits encoded)?

your latest comment confused me.

just because the initial track before MQA encoding was 44.1/16 doesn't mean that the FLAC container after encoding is also 16 bits.



you will probably find the answer in my comment above. MQA CD is lossy in the bits that matter.
Its MQA CD. I'm not aware of any files that come as MQA 24 bit 44.1khz other than the demo file provided by 2lno. Everything on tidal is 16/44.1, and so testing was done with that given as that is what is being served to everyone.

Additionally, reports about what bit depth MQA uses for the file vs "extra information" vary. Last I saw was them claiming they use '15.85 bits' for the main file. Though again, they've not provided any evidence or explanation for this either.

Additionally, I just did a further test by truncating the bottom 3 bits of both the redbook and MQA files, and they still exhibit large differences. So that doesn't seem to be the cause.

EDIT: Just to clarify, the files that tidal serves are 16/44.1 in all cases i've found. MQA then 'unfolds' them to 24 bit and higher sample rates
 

mansr

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#39
As far as I've been able to tell, all MQA files on Tidal are 24-bit. Many of them are, however, made from 44.1 kHz masters, quite pointlessly.
 

abdo123

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As far as I've been able to tell, all MQA files on Tidal are 24-bit. Many of them are, however, made from 44.1 kHz masters, quite pointlessly.
That’s has been my experience with Tidal too. The vast majority of MQA tracks are in 24-bit FLAC containers.

I have no idea how he ended up with all tracks he tested being 16 bit.
 
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