MQA - A clever stealth DRM-Trojan (CCC talk)

Discussion in 'Audio Hardware' started by Ric-Tic, Mar 12, 2018.

  1. John Schofield

    John Schofield Forum Resident

    Still LMAO SqishySounds! Thanks for injecting some humor.
  2. TarnishedEars

    TarnishedEars Forum Resident

    Seattle, WA
    That is one possible interpretation. But I'm not sure if it is necessarily the correct, or the only interpretation. My interpretation is that they are referring to all of the phase shifting which is produced by various low pass filtering techniques which are applied on both the recording and on the playback sides of the chain. Phase shifting by definition is going to result in some very slight relative timing differences at various frequencies. So this is what I suspect that they are going after. Now whether this is either important, or audible is a whole separate argument...
    Last edited: Mar 12, 2018
    tmtomh and Kiko1974 like this.
  3. Kiko1974

    Kiko1974 Forum Resident

    That's why Hi Res uses high sampling rates, what effects can have those filters on the audio range when sampling at 176.4 or 192 Khz?
    harby likes this.
  4. Erik Tracy

    Erik Tracy Meet me at the Green Dragon for an ale

    San Diego, CA, USA
    The gist of the presentation in the opening post is that Hi Res is much ado about nothing audible - higher sampling rates and bit depth over redbook are useful for archival purposes only and have no audible ramifications for end listeners.

    So...take that for what it's worth.

    The deblurring/time smearing claims by MQA seem to be all about 'special sauce' filtering in the analog domain.
  5. cdash99

    cdash99 Forum Resident

    I've found that this GIF has other uses in my professional endeavors.
  6. tmtomh

    tmtomh Forum Resident

    TarnishedEars is correct: MQA "deblurring" is about correcting for phase shifts cause by filters in the digital equipment in the recording and playback chain. It has nothing to do with jitter reduction (no offense intended to Rolltide - just saying).

    The problem is that it only works if:
    1. The components used in the chain are known (for example, what ADC was used during recording? What microphone preamp?)
    2. The chain itself is simple (for example, not a multitrack recording where different individual tracks were recorded at different times and places with different ADCs and mics/preamps)
    So if you have a typical album based on a multitrack mixdown, then deblurring is impossible, because the deblurring filter necessary to compensate for phase shifts from the recording equipment chain on one track could be different, and working at cross-purposes, from the filter needed to compensate for phase shifts from recording equipment chain on another track. Imagine trying to apply a deblurring filter to, for example, Beck's Odelay or even Morning Phase. Which of the multiple different ADCs used for the multitrack tracks, at different sample rates (and therefore requiring different filter frequencies), would be the "right" one to compensate for when applying after-the-fact filtering during remastering of the two-track stereo mixdown? It makes no sense.

    This is putting aside the fact that for a large proportion of recorded music in existence, it's impossible to even know for sure what equipment was in the recording chain.

    Even for recent remasters/reissues of classic material, what exactly was the ADC used when the original analogue tapes were digitized? And what small armies of people at MQA and the record labels are being paid to research the provenance of the 10s of thousands of albums that are supposedly in the pipeline to be released in MQA versions?

    Now, in fairness to MQA, I will say that there is one key aspect of MQA DRM that, while the worst from a consumer point of view, does have some theoretical merit: The final "unfold" of MQA files happens only during hardware playback, because theoretically MQA applies a final digital filter customized to whatever DAC the MQA file is playing through - and of course MQA cannot know beforehand what DAC you will be playing their files through.

    But again, the problem is that deblurring filters to compensate for digital equipment used in recording and playback are conceptually an interesting idea, but in practice impossible to implement because no one will ever have enough knowledge of or control over the recording and playback chains to make such filters effective.

    So what you get is an MQA file that you can freely copy and back up and play on non-MQA devices - but you cannot copy and back up and play the full-resolution, unfolded and decoded musical content. You get that only during playback - and that is a form of DRM.

    It's as if CDs stored music in, say 13-bit, 32kHz form, and the full 16-bit, 44.1kHz resolution were "encapsulated" in an encrypted data stream in the 13th bit. Only when playing the CD in your CD player, with a proprietary, licensed chip inside it, would you get to hear the full 16/44.1k file. You could rip and copy that file and put it on your other devices - but if those devices were not licensed, then they'd only play back the crippled 13-bit, 32kHz version. That's what MQA is (except of course the relevant bit depths and sample rates are different).

    And in that context, when MQA must know the severe, show-stopping practical limitations of their deblurring system, it is in my view dishonest of them to keep promoting deblurring (and the DRM that goes along with it) the way they have.

    Finally, it is important to know that several major labels have purchased what is reportedly a 21% ownership stake in MQA. That means the labels get a chunk of the licensing fees that MQA charges for MQA-certified ADCs and other studio equipment, as well as the licensing fees they charge DAC manufacturers. And they also get a chunk of the fees MQA charges Tidal and other companies that buy MQA versions of the music in the record labels' catalogues. And the equipment licensing fees are free from any artist royalties.
    Last edited: Mar 13, 2018
  7. TarnishedEars

    TarnishedEars Forum Resident

    Seattle, WA
    Very well stated tmtomh. The only point which I you might have missed is that many recording have been deliberately made to sound exactly the way that they do; warts and all. And even if MQA works exactly as advertised (doubtful IMO), it may be that this deblurring process actually changes the sound of some recording in such a way that the end result is not what the producer originally intended.
  8. Rolltide

    Rolltide Forum Resident

    Vallejo, CA
    None taken. What you describe is far dumber then jitter. I'm almost hopeful this leads to a new era of audio virtue-signalling:

    "Why the turntable, Chauncey? I thought you were a digital guy!"

    "It's the temporal blurring on my digital files. Now that I know what to listen for, I just can't get over how awful it sounds. Its like when I suffered from the hash and grain, but at least in that case I could solve it by buying an Esoteric-Binford 9000 CD player. But this? This I dunno. I just dunno."
  9. ZenArcher

    ZenArcher Forum Resident

    Durham, NC
    It seems to me MQA prevents the use of bass management, digital volume control or equalization, or indeed any kind of processing by the consumer? And if an MQA track is streamed to various points in the home, wouldn't every single endpoint device need to be licensed and MQA-compliant for full resolution? If my understanding is correct, these are huge issues.

    The technical and sound-quality arguments don't sound compelling to me. It would, however, create a new revenue stream for labels which would offset their poor financial performance of late. If I could be assured that artists would be the primary beneficiaries, I might almost be ok with it. Somehow the artist always gets the short end of the stick.
  10. missan

    missan Forum Resident

    I think there is no harm in MQA, as long as there is a SQ benefit for the customer.:biglaugh:
    quicksrt and gabbleratchet7 like this.
  11. tmtomh

    tmtomh Forum Resident

    Your understanding is basically correct.
  12. Dr Tone

    Dr Tone Forum Resident

    Calgary, AB
    I'm quite certain the majors are using a standard MQA profile and an automated process when pumping out the MQA. So the original mastering engineer is not involved in the MQA process. Not sure how they feel this is "authenticated" in way or form.
  13. tmtomh

    tmtomh Forum Resident

    Exactly. It's a minimum-phase filter and not much else.
  14. TarnishedEars

    TarnishedEars Forum Resident

    Seattle, WA
    I think that this would only be an issue if your MQA capable DAC also contains your room correction. If your MQA DAC's output is fed into a processor which contains your room correction, then this should not be an issue.
  15. Waynefi

    Waynefi Confused over the confusion ?

    Northern Ohio
    I have tried my hardest to not really care, but it's hard to not say anything. I really do not look at MQA as anything more then a way to stream HiRez files form a source like Tidal, I really cannot understand why anybody cares. I have an MQA device to decode MQA from Tidal. Comparing SQ of a redbook on Tidal verse a HiRez MQA title on Tidal, the HiRez version usually sounds better, just like it generally should. I really do not care how MQA accomplishes this. If we could easily all stream 24/192 files from Tidal or anybody else, without MQA, then why aren't we ? It is a way to hear HiRez version of an album, without buying it. If I really like it, I then can buy the SACD, previous DVD-A, or a HiRez download from AS or HD. Or just listen occasionally to a cut or two from the Tidal MQA.

    To me it is a streaming issue from a source like Tidal, if you don't want the option, don't buy that option on the products you own. There are all kinds of variously priced MQA capable units available. There is all kinds of music you can stream without it. I hear some paranoia that MQA will be everywhere, and you will be forced to have it, to listen to any music ? If so that would be bad, but to me far fetched. I really cannot find a reason there should be any fighting about it ? I enjoy it for streaming , but would not see any reason to buy and MQA download.
    Last edited: Mar 14, 2018
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  16. ZenArcher

    ZenArcher Forum Resident

    Durham, NC
    But isn’t about 99 percent of these functions performed today in the digital domain, before the final DAC stage?

    I’m also assuming it’s hoped that MQA will eventually be built into integrated amps and receivers. Is the idea that these functions will now be done in the analog domain? If even possible, that’s an enormous step backwards.
  17. TarnishedEars

    TarnishedEars Forum Resident

    Seattle, WA
    I doubt that very many people running HT receivers as their primary source will even know what MQA is, much less care. MQA seems to me to be getting marketed to audiophiles who care about very subtle sound quality differences that normal people aren't even aware of. And the vast majority of these people run separates in my experience.

    So I don't think that HT receiver owners are the market segment which this technology is being marketed to. And MQA encoded files will still play through such a receiver, just not in an unfolded form.

    And I'm not sure if such devices exists yet or not, but it is theoretically possible to insert a room-correction processor in-line with a digital stream along the lines of an SP/DIF stream between a streamer, a computer, or a CD player's digital output and, before your discrete MQA DAC. Or the analog outputs of an MQA DAC could be fed into the analog inputs of an HT receiver/Pre-processor which features room corrections.
    Last edited: Mar 14, 2018
  18. Claude Benshaul

    Claude Benshaul Forum Resident

    There is a potentially big issue with those of us using a PC to play and DSP. Room correction might not be an issue since it can be done in the analog domain (probably), but volume leveling is, in my opinion, a critical part that won't co-exist with MQA.

    Anyway, that isn't going to be solved on this forum or in any other place where music lovers are exchanging ideas, as MQA demonstrated many time that they are not interested in conducting dialogues with end users. What I find rather hilarious is that after the posts exchange between @LeeS and @Archimago about the neuroscience behind MQA, it turn out that it's based on research that has limited, if any, relevance.
  19. Shiver

    Shiver Forum Resident

  20. Waynefi

    Waynefi Confused over the confusion ?

    Northern Ohio
    Well I am still confused ? DSP, HT Receivers , surround sound, computers. Do we have a way to stream 2 channel 24/192 files from on line from a source like Tidal realistically without MQA ? If somebody finds a cost effective way to do this without MQA it will go away.

    Folks this is a way to stream on line 2 channel HiRez files, that is it as far as I am concerned. If you want to hear it properly, you need properly equipped device to do this. I do not see it any different then being forced to buy a SACD, DVD-A, Blu-Ray capable players if you want to use that software. Just like those players, and the MQA decoder you do not have to have any of that to listen to music. I have enjoyed most of the Tidal MQA titles I have listened to, just like I listen to DVD-A, SACD and HiRez downloads I buy from HD and AS.

    I still ask why all the paranoia ?
    gabbleratchet7 likes this.
  21. It already is possible to stream 24/192 from an online source without MQA. Qobuz is one service that can do it. 24/192 FLAC or ALAC is about the same bitrate as 1920x1080 HD video from Netflix. If you can stream full HD video from Netflix you can stream 24/192 audio. The bandwidth isn't a problem now, and bandwidth will only get easier and more available as time moves forward. The bandwidth necessary for 24/192 and 24/96 for stereo audio is easy.

    I can even stream 24/192 to myself using my home network. I can set up JRiver Media Center's Media Network to privately stream audio to me when I'm away from home. It can do high-res 24/192 streaming. I can go to a coffee shop, get on their wi-fi and stream high-res to myself if I want. It works. And no need for MQA to make that possible. 10 years ago MQA would have solved some existing bandwidth challenges for high-res audio streaming. But now? No. The introduction of MQA is 10 years too late to be relevant for solving the high-res streaming problem.
  22. wgriel

    wgriel Forum Resident

    bc, canada
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  23. Waynefi

    Waynefi Confused over the confusion ?

    Northern Ohio
    Yes and Qobuz is not here yet, it is supposed to but I will believe when I see it. I understand some get Qobuz through some work around , but until it is here officially I am not interested worrying about it. Not to mention the price of the premium service for unlimited HiRes streaming looks to be pretty expensive. So as I said, we do not have this service officially in the US to stream 24/192 files. If it gets here, and it is a good, whatever happens to MQA will take care of itself, as long as the price is not overly high compared to Tidal. I am ready with my system for both. Like I said why all the paranoia ?
    billnunan likes this.
  24. ZenArcher

    ZenArcher Forum Resident

    Durham, NC
    As you have not educated yourself on this topic, I suggest reading Archimago's article referenced above. You may not agree, but you will understand the issues from one perspective.
    rednedtugent likes this.
  25. The reason we don't have more high-res audio streaming right now is that the streaming services and labels don't wanna. High-res audio streaming has been technically possible for many years. When it became practical for Youtube and Netflix to stream 1920x1080 HD video it became equally possible and reliable to stream 24/192 audio. 24/96 audio is half that bitrate, so is even easier and more reliable to stream. Yet the labels and services were still unwilling to stream 24/96 lossless audio even though the video services were streaming video at higher bitrates. The problems for streaming high-res audio aren't technical, they're business. The labels and streaming companies just don't wanna do it. That's not a technical issue. We've had the technical ability to stream high-res audio for well over 5 years. If we'd have just known to click our heals three times it would have been here already. I had the home bandwidth to stream high-res audio 10 years ago. Lossless high-res audio streaming is no longer a technical problem. MQA hasn't changed that.
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