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

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Grooved

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This, I think is another problem with MQA. Before MQA we could (mostly) assume that a flac file contained lossless audio, but now, because they chose to use flac a container, we cannot anymore :-(
Right, but from my POV, I'd not use the "lossless audio" argument like that, more than there can be a difference in sound.
I say that because I think most higher than 16/44.1 content is available onyl if the production uses higher than that, and moist of the time, it's not to provide a better sound by offering a Hi-Res version, it's just that the production chain uses this sample rate because it was a need to work correctly (for example depending on any plugin used). Some work at 44.1, some at 48, some at 88.2... because they hardware works best at this frequency, and that's all. If for someone, it's 88.2, then you get a 88.2 master file in the end. But once again, we can't generalize
 

gatucho

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edahl post: 754804 said:
We agree about that!


It's not really being pushed down anyone's throats though?

Except that IT IS! At least it is by Tidal, since now I cannot choose red book FLAC for tracks with "master" tag. Only way to avoid MQA is to use lower quality streaming (ACC). That's the part of "pressing our noses so we open the mouth" of pushing MQA down our throats.
 

Tks

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I seriously don't understand why would they ever do this. they still have to host two different files for the same track (as Hi-Fi is without the tagging).

there is not a single reason i can think of why this would be a good idea.
They have not. I have offered to do tweaked testing based on some of the criticisms in their original response but I've not heard anything.

I have had contact from a few manufacturers though with some.....interesting information regarding how mqa has forced manufacturers to alter their products before they'd be allowed to implement mqa.

I need to get a couple things verified but there may be a followup video at somepoint.

Sounds good, I thought since you were silent for a bit, maybe you were in backroom talks with them or something. Pretty unfortunate that they've decided to cuck back into the shadows again. As for that follow-up from manufacturers, that sounds very interesting. I never imagined MQA was anything more than an add-on. Though I do recall a bunch of MQA DAC reviews here causing issues with bugs of normal operation (like the MQA portion not diengaging fully or just cause weird glitches). So aside from the the annoying stipulation about having digital-out, I didn't imagine manufacturers had to contend with anything other than marketing departments stipulating that getting the MQA certification is something engineering needs to take into account.
 

KeithPhantom

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that by definition replaces the original noise floor with real information dithered as to still appear as noise to a normal DAC
What? 1. You can just dither a 16-bit file and get about 20-bit ENOB and this is more useful than generating useless ultrasonics that most likely are not correlated with the original signal. 2. Your process affects the noise floor of the recording and you cannot recover this by unfolding. Trading noise floor performance for unhearable ultrasonics is not what I call a fair trade. I don’t think anything MQA reconstructs is useful, since all focuses in frequencies above 20 kHz, where there’s not much content either way.

you will get gigantic differences: that noise floor which you are expecting to find as an exact copy doesn't exist anymore in MQA
No, the noise floor increases and you create garbage at >20 kHz. And if you’re going to say that you can use NS for MQA, the same is applicable to regular FLAC.

gain space for real information in what's garbage in the source file).
Don’t you think the designers of the CD standard and posterior formats waste preciousamounts of information just in noise? Also, define “real information”.

As a crude analogy, I t's like these test are comparing a file copy of a bunch of data done from an old, highly used hard disk, to a fresh new one. Files copied are "lossless" (that's what MQA claims, I agree, rather carelessly); then Archimago and GoldenEar are not looking if those files are identical (the music) but comparing each sector of each disk against the other. The first one, with all file fragmented and rest of old files deleted (the noise floor) is obviously different form the contiguous files encountered in the new disk. This new disk also doesn't contain all the garbage of those hidden erased files from the old one. Thus, it is "lossy"!, I will close my Tidal account!! They are lying to me!!! I may even build a case for seeing them!!!!
The files aren’t lossless at all. Even when unfolded, they should be bit perfect to the original recording (the intent of the artist), but they aren’t. They even have issues in the main audio band (20 Hz-10kHz).
 

Rusty Shackleford

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To the extent the argument is that MQA is going to take over the world and will get rich from it, you have to explain why you are perfectly OK with companies who have already done that times 1000. If you are an Apple customer as I noted, you have already lost any argument as to why what MQA is doing is a bad thing. Clearly far more bad things are Ok with you so opposition to MQA must have other reasons.

Apple's business practices have nothing to do with MQA. This is whataboutism. The "other reason" to oppose MQA is that it claims to be lossless, and it isn't. It claims to be superior to PCM, and it isn't. It's a fraud.
 

Grooved

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You are welcome to open a new thread with a specific drill down topic. Keeping it on track and subject focused is the problem. I am willing to give it a go if the Member who makes the new thread helps keep the conversation on point. ;)

Thanks for the suggestion, I will think about it, my main concern is that I don't have a fix "available time" for that which mean I can be out of the thread for several days...
I find MQA interesting despite the "false" claim, from them or from providers, but the main thing I don't get is how you can say that you deliver what the artist/enineer want you to listen when they are working and creating and so listening on PCM (or DSD), and not via an MQA realtime processing.
The point I also find important is that we are comparing a thing that is a format+processing (the folded version is not as good as the unfolded one) to other formats not linked to a processing.

Anyway, before starting any new thread, I think this video can help understanding some things on sampling rate at the production stage, this can explain why when your working environnement is different and may need a higher sample rate, we end up with a 96kHz file in streaming service, but not because 96 was SOUNDING better than 48. It can also be usefull in the analysis later :
 
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gatucho

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I'm debating. Whats missing in this discussion is an objective test of the noise added to 44.1 by downfolding realistic but aggressive ultrasonics. I spent years in the lab testing lossy codecs, and @amirm is right, high level ultrasonic tone bursts or square waves will tell you nothing about the ultrasonic noise that is actually folded into the audioband with real music. This may not be a huge issue to audibility and may just look like excessive dither. We don't know.

Tidal also has the best android eq through uapp, and the best quality lossy encoder so I will probably keep it for those.

But it royally sucks that Tidal is selectively but increasingly ripping us off by delivering 13 bit files as lossless.

That's a slippery slope. Then we should be able to validate the user of "lossiER" codecs as ACC if most people can detect in blind tests. OK, so all the apeal of lossless and Tidal has gone down the drain then... For MANY years the main appeal of Tidal was the availability of lossless CD quality Flacs (at least to me and Im sure that for many others). It isn't like their library, interface, etc is top notch, really.

"best android eq through uapp": OK I also like that one! However, it is useless when decoding MQA due to "bit perfect" requirement, so... MQA again spoils good things in exchange for I dont know what...

This: "it royally sucks that Tidal is selectively but increasingly ripping us off by delivering 13 bit files as lossless."
 

ebslo

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I seriously don't understand why would they ever do this. they still have to host two different files for the same track (as Hi-Fi is without the tagging).

there is not a single reason i can think of why this would be a good idea.
To make sure the master version sounds better than the hi-fi. Effectively, they are surreptitiously degrading the "flac" so that when the "master" MQA is partially un-degraded by unfolding, the "master" sounds better.

Slightly less cynical reason, maybe they save storage by having the server strip the MQA flags on transmission.
 

amirm

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Does that mean that selling $500 speaker cables is OK because some sell $50000 speaker cables?
No. It means if you are happily buying 50000 cables, you don't get to complain about the 500 ones.
 

symphara

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I suppose FLAC supports optional blocks, so there can be 44.1/16 as a standard stream and high-resolution data as an optional block. This would be backwards-compatible if players skip blocks they don't understand instead of barfing.
I don't actually know, I haven't looked closely at the FLAC container. Some developers are more forward-looking and provide OOB (out-of-band) data support into whatever format they develop, for future extensions. As far as I'm aware, Atmos is done like this.

And high resolution FLAC isn't?
No, I don't think it is. If you have a high-resolution PCM FLAC file it can only be played on something that can decode that specific high resolution.

There are amplifiers and streamers that support some DSD for example, like base 5.6MHz, but don't support DSD512, and it's not backward compatible.

I think the idea behind MQA is one I've often seen in software engineering - treat some part of the data as OOB, especially if it has little or no impact on a normal decoder, then put something else there. For example, watermarks in JPG files. Or secret messages. In the case of MQA, I think they wanted to enhance the part that you hear by using bits that they considered largely irrelevant.

I'm not commenting on whether they succeeded or not. I simply wanted to clarify what I think @amirm wanted to explain and was widely misunderstood.

Whether MQA does it well, or whether it does it at all, I don't know. I'm not privy to the format or the encoder. I understand the ideea and I don't personally think it's a terrible one.
 

KeithPhantom

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voodooless

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If you have a high-resolution PCM FLAC file it can only be played on something that can decode that specific high resolution.

almost any software will have no issues, especially if it’s provided by the streaming service. And it not, your OS will most likely solve the problem for you. This is a non-issue.

There are amplifiers and streamers that support some DSD for example, like base 5.6MHz, but don't support DSD512, and it's not backward compatible.

DSD is not ubiquitous, and therefore resampling support is limited, and also not easy and CPU heavy. DSD should be banned together with MQA.
 

KeithPhantom

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symphara

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Amplifiers don’t support formats. They just amplify analog signals.
Is that really the best you can do? When I say "amplifiers" I'm obviously not talking about pure analog ones, which are today, as I'm sure you know, a small fraction of the market. Most amplifiers are integrated, and increasingly more of them support UPnP, streaming services, USB etc. Thus they have all sorts of inputs and support for multiple formats. If you also quoted the next two words from my post perhaps it would have been clearer.
 

mieswall

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What? 1. You can just dither a 16-bit file and get about 20-bit ENOB and this is more useful than generating useless ultrasonics that most likely are not correlated with the original signal. 2. Your process affects the noise floor of the recording and you cannot recover this by unfolding. Trading noise floor performance for unhearable ultrasonics is not what I call a fair trade. I don’t think anything MQA reconstructs is useful, since all focuses in frequencies above 20 kHz, where there’s not much content either way.


No, the noise floor increases and you create garbage at >20 kHz. And if you’re going to say that you can use NS for MQA, the same is applicable to regular FLAC.


Don’t you think the designers of the CD standard and posterior formats waste preciousamounts of information just in noise? Also, define “real information”.


The files aren’t lossless at all. Even when unfolded, they should be bit perfect to the original recording (the intent of the artist), but they aren’t. They even have issues in the main audio band (20 Hz-10kHz).

A- read the MQA papers. The process of dithering of data coming from upper folds is CLEARLY explained, even in annoyingly detailed terms. BTW: ultrasonics are relevant not because they are not listenable, but instead because they are important in time coherence. According MQA and the dozens of papers of neuroscience they cite, as important as the audible band.

B- No, that's not correct (well, it does increase very slightly in a narrow band of the 20-20khz spectra, but in non-audible terms). They replace that noise floor with the slice of relevant data captured from upper folds.

C- "real information": In this context, it is called "music": the ever smaller space occupied by music the further you rise in frequency, as captured in ADC. Most bits in lower frequencies, progressively less the higher in frequency you move. The remaining bits in Redbook are wasted space, from that MUSIC recording perspective. If you were registering other unknown profile data, your assumption that the whole space would need to be preserved would be right. MQA deals with music, not with the Perseverance photos sent from Mars.

D- They can't be lossless when unfolded: to be "lossless" in these Taliban terms, both noise floors must be identical, and by definition that noise floor doesn't exist anymore in MQA, as it was replaced with useful information, that a normal DAC still sees as noise, but a MQA DAC knows to decode as information.
 
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GoldenOne

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Sounds good, I thought since you were silent for a bit, maybe you were in backroom talks with them or something. Pretty unfortunate that they've decided to cuck back into the shadows again. As for that follow-up from manufacturers, that sounds very interesting. I never imagined MQA was anything more than an add-on. Though I do recall a bunch of MQA DAC reviews here causing issues with bugs of normal operation (like the MQA portion not diengaging fully or just cause weird glitches). So aside from the the annoying stipulation about having digital-out, I didn't imagine manufacturers had to contend with anything other than marketing departments stipulating that getting the MQA certification is something engineering needs to take into account.
Nope no contact from them (though if anyone from mqa is reading this I would still be keen to speak with you to sort out some tests that would be agreeable to both.)
One reccuring theme I've heard from various manufacturers is that mqa is becoming quite... Pushy about how not just mqa, but non-mqa content is handled.

This is a direct quote from a manufacturer that spoke to me:

"Now, the MQA file, un-unfolded, is usually a 44.1kHz or 48kHz file, while unfolded it is played at the highest sample rate supported by the player that is a multiple of these rates (so e.g. 352.8 / 384kHz / 705.6 / 768kHz). There are few to no DACs out on the market that can handle a switch from e.g. 44.1kHz to 705.6kHz without an interruption to the sound, well, I should say I am not aware of any such DAC and certainly none of our company's devices have one, not even sure if it's theoretically possible. This is the reason for the interruptions to the sound many of our users are reporting when beginning to play an MQA track, seeking through it, skipping to another track, basically anything other than playing a whole MQA album in sequence.


Now, MQA understandably do not want to want this to happen to their audio, so the recommendation to all of us, is to resample all incoming audio to their highest 44.1 / 48 multiple, regardless of whether it's MQA, in a manner consistent with MQA unfolding so that no break in the sound would occur.


If we followed this recommendation, we would have to abandon the [name redacted for company anonymity] for bit perfect rendering of PCM audio at different sample rates."
 

KeithPhantom

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Is that really the best you can do? When I say "amplifiers" I'm obviously not talking about pure analog ones, which are today, as I'm sure you know, a small fraction of the market. Most amplifiers are integrated, and increasingly more of them support UPnP, streaming services, USB etc. Thus they have all sorts of inputs and support for multiple formats. If you also quoted the next two words from my post perhaps it would have been clearer.
So say integrated. I was just referring to the word “amplifier”.
 

Rottmannash

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Video is up.
I'll be writing a full written version which will be posted here, head-fi, audiophilestyle etc, and will share the original masters, MQA encoded versions, and unfolded (both first unfold and analog recording of full decode) versions so others can test and look into the files themselves too.

MQA did respond to me, and their response is discussed at the end of the video (timestamps in description and playbar)
Is this you?
 

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