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

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Can we all please stop "MQA = DRM meme? It's honestly ridiculous.

Are you good with crippleware?

Are any or all MQA devices able to select an alternate reconstruction filters?
Are any platforms other than Roon allowed to apply PEQ/REQ?

- Rich
 
Simple proof: Listen to the attached files.
Suppose we are downsampling a file to 12kHz sample rate, then the file should be filtered in a way that there is no content >= 6kHz before decimation. Due to the low 12kHz sample rate, everyone must be able to hear a faint tone in the attached "impulse long linear.wav" and "impulse long minimum.wav", but not in "impulse short linear legal.wav" and "impulse short linear illegal.wav".

"impulse short linear illegal.wav" is named as such because the stopband is >= 6kHz before decimation. After decimated, aliasing will occur down to about 5kHz. I aware that some people tend to use imaging and aliasing interchangeably, it can cause confusion, so here is an explanation:
https://www.audiosciencereview.com/...u-m4-audio-interface-review.15757/post-504008

However, 44.1kHz sample rate is the lowest norm for music distribution, so people needed to be able hear the same effect at around 22kHz, and the audio content itself also need to contain strong signal at this frequency region. Also, the "long" files can only happen on something like a chord DAC, for typical DAC chips, the "short" files are the norm.

Therefore it is all about frequency domain.

In the case that anyone interested in trying these things out with real music rather than an impulse, @KSTR provided an interesting listening test here:
https://www.audiosciencereview.com/...ike-if-we-were-bats-listening-examples.23776/

People who spread FUD about "ringing" and "time domain accuracy" don't even listen to these kinds of music. First few seconds from OST CD attached.
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MQA content is distributed with no copy protection. I see no reason for the labels to bring any kind of DMCA claim against you or even want to be involved. The business end of this will be patent and copyright infringement of the code, not the content.

This will help you to understand that access controls and copy protection are not exactly the same thing.

https://www.dmlp.org/legal-guide/circumventing-copyright-controls

Note that I'm not asserting that the DMCA is applicable in the case of MQA. I make no such claims either way. Rather, that it takes someone who understands the case law to render any kind of useful opinion on this subject, not a layperson like you or me.

Meanwhile, your prediction of what the labels will and won't do is hardly comforting. Corporate intellectual property owners have a long history of asserting digital copyright violation and DMCA violations, even when a violation would probably not be determined in court. That is because individuals can't afford to spend $150K or more to defend their usage.

I recommend the EFF or the works of Lawrence Lessig as useful resources for learning more about that history.
 
"Appears" is the key word here. A bunch of guessing on Archimigo's part with incorrect assumptions. I just analyzed the spectrum of this 88 kHz. Here is the scan of the first minute or so of this track:
...
I went to look for the original master and nothing beyond 44.1 kHz/24-bit is available. This support the notion then that the roll off is correct around 22 kHz and what is after is noise shaping.

You are wrong, Amir.

For starters, Archimago's source file was 44.1kHz, MQA-encoded. He wrote that clearly here https://audiophilestyle.com/ca/reviews/mqa-a-review-of-controversies-concerns-and-cautions-r701/.

That recording, regarded at 44.1kHz, rolls off at 21kHz and that's it. You claim to have investigated an 88.2kHz version and found the same roll-off. Fine. That just shows that your 88.2k version is an upsample of the 44.1, i.e. fake hi-res, an upsample done outside any MQA regime.

When you play the 44.1k MQA stream through Tidal, with Tidal MQA unfolding enabled, then Tidal generates a 88.2k stream, with the spectrum as demonstrated by Archimago, and by many others (by using digital capture after Tidal, obviously, and not some external ADC with all the errors that one can introduce).

The ultrasonics above 23kHz truly are images of the original <21kHz signal. They are there because MQA clearly specifies the reconstruction filter for CD-rate material, and we have known for years now that this is a very short, leaky filter, a filter that exactly produces what has been seen by Archi.

If you took the same 44.1k MQA stream and sent it, unmodified, to an MQA DAC, then its analogue-domain output would look the same.

I wonder what the fuzz is all about, because this really is no news.
 
The steeper the FIR filter the more taps you need, the longer your impulse response is..
You need proof for that?
I don't know what specific tradeoffs the GP was referring to in the following:
And slow filters absolutely trade of frequency for time.
but to me, optimal time domain response is not a "slow" filter. Optimal time domain response gives the fastest rise and fall times possible while still guaranteeing no overshoot or undershoot. This optimal time domain response is realized by a Gaussian filter which is usually implemented as an FIR. As with other types of FIR, the quality of the approximation increases with the number of taps and corresponding increase in impulse response length.
 
Archimago's source file was 44.1kHz, MQA-encoded. He wrote that clearly here https://audiophilestyle.com/ca/reviews/mqa-a-review-of-controversies-concerns-and-cautions-r701/.

That recording, regarded at 44.1kHz, rolls off at 21kHz and that's it. You claim to have investigated an 88.2kHz version and found the same roll-off. Fine. That just shows that your 88.2k version is an upsample of the 44.1, i.e. fake hi-res, an upsample done outside any MQA regime.

There are three MQA versions of this album on Tidal - two 16 bit, one 24-bit. Which version did Archimago and Amir analyze?

John Atkinson
Technical Editor, Stereophile
 

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That's probably not correct re. public domain decoder. This is strictly MQA patent issue.

And in case of the current public domain decoder developed by @mansr , they chose not to legally pursue this matter.

Assuming his decoder reads on MQA's GB patents, his activity should not be considered illegal. European patent law typically limits patent infringement to commercial activities (e.g., selling the decoder). It would be a different matter here in the U.S. where infringement could also extend to non-commercial use.
 
This will help you to understand that access controls and copy protection are not exactly the same thing.

https://www.dmlp.org/legal-guide/circumventing-copyright-controls
It may help you to read it: "You may come across digital works that contain copyright controls, such as digital rights management (DRM) technology or a software copy protection system. "

We are no talking about digital works that have DRM or content protection. As I explained, the MQA file is transmitted in the clear and can be readily copied with no restrictions whatsoever. Therefore there is no intent on the part of content owner to protect said file.

Note that I'm not asserting that the DMCA is applicable in the case of MQA. I make no such claims either way. Rather, that it takes someone who understands the case law to render any kind of useful opinion on this subject, not a layperson like you or me.
You are the lay person, not me. I spent a lifetime meeting with record label executives and their lawyers as they attempted to force operating systems/players to limit playback of their content. Most of their execs come from licensing department so are lawyers as well. I have explained repeatedly how Steve Jobs convinced them to distribute their content without any copy protection. And how you can go to sites like HDTracks, and download millions of high-res audio tracks with zero content protection in your favorite (non-MQA) format.

As a business policy then, labels do not care about content protection. Yet you want to imply they would care that someone has built another decoder for MQA where their content is no more at risk than it was before? Talk about reach and lay debating tactics.

Meanwhile, your prediction of what the labels will and won't do is hardly comforting. Corporate intellectual property owners have a long history of asserting digital copyright violation and DMCA violations, even when a violation would probably not be determined in court. That is because individuals can't afford to spend $150K or more to defend their usage.
There is no digital copy protection issue for content here. There hasn't been one, there will not be one. As a lay person you can imagine anything you want but don't drag me into it. I know the reality, you don't.

I recommend the EFF or the works of Lawrence Lessig as useful resources for learning more about that history.
I wouldn't. Lessig went through a painful battle with the labels which he lost when labels cared about content protection and cared a ton. Since then Lessig has become enemy of anything related to copy protection. So if you want to read a one-sided argument, sure, go ahead and read it. But even he wouldn't tell you that you have a case here when the content itself lacks any form of copy control or protection.

All of this misses common sense. MQA would be the entity that would have a claim here and I am sure they can hire enough lawyers to make your life hell if they wanted. If the labels were upset, they would probably push MQA to do this enforcement since it would be free to them and MQA would have the real case.

That said, if MQA becomes wildly popular, open-source versions will be developed quick and get distributed like wild fire. No one will be able to stop them. Your commercial software won't be able to use them for liability reason but you all who are fans of open source and such will have no trouble decoding MQA.

Really, if you are a lay person with no knowledge of the law or industry, I suggest not even engaging in this topic.
 
The next step in audio realism will be 3D audio which is highly reliant on DSP processing for most environments.
One of the dumber plays by MQA was insisting on a leaky reconstructing filter and it seemingly restricting DSP processing.

I don't see MQA muscling in on Atmos audio.
Dolby initially tried to restrict Dolby sources to their upmixer to (IMO) squeeze out the competition, DTS and Auro-3D.
They backed off that and thanks to Audioholics for their push-back.
Dolby to Restrict Non-Native Upmixing on Atmos Based Products | Audioholics

Atmos audio at Redbook or better resolution would be a nice addition.
Movies can have excellent sound tracks with greater dynamics the DR constricted music.
Although, recent titles are employing steep bass limiting starting at 30 Hz.

- Rich
 
Are you good with crippleware?

Are any or all MQA devices able to select an alternate reconstruction filters?
Are any platforms other than Roon allowed to apply PEQ/REQ?

- Rich
I don't see my MQA DACs as crippled.

Some do have alternative filters for non-MQA playback (UDP-205, M2TECH, D90), others don't (Liberty).
 
I don't see my MQA DACs as crippled.

Some do have alternative filters for non-MQA playback (UDP-205, M2TECH, D90), others don't (Liberty).

Unless you pay the royalty, the DAC playback MQA encoded titles are crippled, thus crippleware.

- Rich
 
Unless you pay the royalty, the DAC playback MQA encoded titles are crippled, thus crippleware.

- Rich
Sure, there are many such things, Dolby for example. But we don't seem to have passionate discussions about that, only MQA.
 
Sure, there are many such things, Dolby for example. But we don't seem to have passionate discussions about that, only MQA.

Dolby adds value and does not restrict DSP and other post processing while increasing costs.
Multi-channel audio from music streaming is new and welcome.

MQA degrades quality and restricts while increasing costs.
There is nothing added by MQA.

Both have marketing, but MQA is blowing epic levels of smoke, well you know where.

- Rich
 
Dolby adds value and does not restrict DSP and other post processing while increasing costs.
Multi-channel audio from music streaming is new and welcome.

MQA degrades quality and restricts while increasing costs.
There is nothing added by MQA.

Both have marketing, but MQA is blowing epic levels of smoke, well you know where.

- Rich
Fine, but obviously many audiophiles feel that MQA adds value to them and are willing to pay $0-100 extra for it.
 
Fine, but obviously many audiophiles feel that MQA adds value to them and are willing to pay $0-100 extra for it.

I am not sure the audiophile community is a bastion of rational behavior.

Since disk space and bandwidth are not a problem, there is no justification for MQA, unless you buy into leaky filters and increased THD/decreased SINAD.

- Rich
 
I am not sure the audiophile community is a bastion of rational behavior.

Since disk space and bandwidth are not a problem, there is no justification for MQA, unless you buy into leaky filters and increased THD/decreased SINAD.

- Rich
There is no need to save anyone :). People will make their own, adult decisions.
 
Are you good with crippleware?

Are any or all MQA devices able to select an alternate reconstruction filters?
Are any platforms other than Roon allowed to apply PEQ/REQ?

- Rich

When MQA first came out, I used get weird stuttering/artifact issues when applying PEQ/REQ to MQA streams. More recently, I haven't had any issues applying PEQ/REQ using Audirvana, BruteFIR, etc. Is this not everyone's experience?
 
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