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

[amirm]

Streaming and download sites are not screening files for their spectrum before posting.

Neither was Tidal until someone complained. Upload the soundtrack of a porn video to one of those services and have someone complain. You think they will continue to keep it up there?

Really, this is the problem: folks with zero knowledge of the field make these totally wrong arguments thinking they are being clever. Don't waste our time.

 

[amirm]

Amir, IMHO, now you're continuing to push the thread in a wrong direction. Rather than giving another round of explanation of how/who went wrong, can we all - including you with your influence, if you can - orchestrate another test? This time collaboratively, and with the right tools, understanding, attitude?

I don't have access to any encoding tools. I do however plan to do some testing of MQA encoded music and see how the ultrasonic reconstruction is working. I have already done one video on MQA where I talked about its problems when decoding is not done. I can give you a link if you have not seen it.

 

[ebslo]

You said where is the objective info in MQA response. I told you it is in there. If you think there is not, then you didn't read or understand their reply. I have already quoted objective analysis from their response:

I verified the spectrum of OP signal and confirmed that the MQA analysis is correct:

So clearly you are not reading either my responses or that of MQA. Please don't waste our time repeating the answers like this.

I think the confusion stems from an expectation that the data presented show something other than excuses for a broken codec.

 

[Raindog123]

I have already done one video on MQA where I talked about its problems when decoding is not done. I can give you a link if you have not seen it.

I would appreciate it.

 

[amirm]

I would appreciate it.

Sure:

 

[BrEpBrEpBrEpBrEp]

Walking back into this thread after 3 hours like:

I gotta say, I'm completely against MQA, but making posts on SBAF implying Amir is in the pocket of Topping (lol) is a really weird and off-putting thing to do.

I feel like if Amir and ASR Mods were in MQA's pocket, they'd probably have just banned discussion of MQA altogether a long time ago.

 

[Pennyless Audiophile]

So, if I understand correctly, MQA could be lossless, or with a very small loss (whatever this may actually mean) but only if the signal resembles an average musical signal.
The encoding in MQA format can and should be "tuned" for the specific music being encoded for the best artistic result.
Since it may well seem, from the marketing material, that MQA is a lossless compression, the Golden One wanted to test this point.
The tracks used, though, were non "musical" in content and the result was that the output was, indeed, different from the source.
This turned out to be against the terms of service so the content was removed.
Since the Golden One made a public video, a public reply was issued.

If I am summarizing correctly, we learned something interesting about MQA. The test that is missing, correct me if I am wrong, is to do the same with a conventional musical track and see what happens and where are the differences. Maybe we can find some musicians who may want to do the test. That should not be against the terms of service, I suppose.

 

[Maki]

Walking back into this thread after 3 hours like:

I gotta say, I'm completely against MQA, but making posts on SBAF implying Amir is in the pocket of Topping (lol) is a really weird and off-putting thing to do.

I feel like if Amir and ASR Mods were in MQA's pocket, they'd probably have just banned discussion of MQA altogether a long time ago.

That's kind of puzzling. Topping is one of the only companies that gives a discount (D90 vs D90MQA) to customers who don't want to pay for MQA. Most other companies just force it on all their customers, whether or not they'll actually use it.

 

[tmtomh]

Neither was Tidal until someone complained. Upload the soundtrack of a porn video to one of those services and have someone complain. You think they will continue to keep it up there?

Really, this is the problem: folks with zero knowledge of the field make these totally wrong arguments thinking they are being clever. Don't waste our time.

And have someone complain. So then obviously Tidal took down @GoldenOne 's tracks because someone complained, yes? And the only one who knew about his tracks' content (aside from GoldenOne himself) was MQA. So logically MQA did indeed get his tracks taken down, yes?

If so, then your earlier point that "it was Tidal, not MQA" that made the decision to take down the tracks loses its meaning, doesn't it? The point is that Tidal didn't know and didn't care, and MQA was decisive in the takedown, yes?

 

[bboris77]

 

[amirm]

And have someone complain. So then obviously Tidal took down @GoldenOne 's tracks because someone complained, yes? And the only one who knew about his tracks' content (aside from GoldenOne himself) was MQA. So logically MQA did indeed get his tracks taken down, yes?

We don't know if it was Tidal or the publisher. The publisher had licensed the encoder from MQA so it is possible it ran foul of their licensing terms and so they decided to pull the plug.

As to your final statement, no, we don't know that. MQA likely contacted the publisher to get the detail/error messages. Publisher then realized what happened and pulled the plug. We have MQA on record saying they did not make any take down requests:

"

1. MQA did not delete his files; that accusation is false. MQA is not a rights holder nor distributor. We do not issue takedown notices to distributors or DSPs."

That is a very strong denial with no counter evidence to say otherwise.

Either way I hope we are all in agreement that neither the DSP (publisher), nor Tidal would be willingly participating in any kind of food fight like this. They were taken advantage of and they responded once they realized what had happened. Neither would have needed pressure from MQA to do so.

 

[Raindog123]

the issues surrounding the anonymity of AES' peer review process

Out of curiosity, what are the AES peer-review anonymity issues?

 

[Raindog123]

Neither was Tidal until someone complained. Upload the soundtrack of a porn video to one of those services and have someone complain. You think they will continue to keep it up there?

They were taken advantage of and they responded once they realized what had happened.

Still, what was wrong with the files, for ‘someone’ to complain? What did happen - how were they taken advantage of? How were the GoldenOne’s files different from >this< (https://tidal.com/album/29581889)?

 

[goldenears]

They were taken advantage of and they responded once they realized what had happened.

I wonder if MQA folding would preserve the ultrasonics in the sound of the world's smallest violin, played to lament the anguish of Tidal/MQA being taken advantage of in such a way.

 

[voodooless]

Some observation here:

I don't really understand the argument that the test files were not suitable, or that encoder warning would be an issue. You have to keep the hypothesis of the video in mind: MQA is lossless.

In that context, it's perfectly fine to put in files with test tones through the wringer. Lossless compression should be able to handle this just fine. The fact that it didn't, the fact that the encoder complained, the fact that MQA states that it can only encode music (whatever that is), means it is not. So I'd say: hypothesis disproved: MQA is not lossless. So, there is no reason to complain that the test tracks were not music, no reason to complain about encoder errors.

In any case, from what I've read on people that have looked at how the compression scheme works, they did not find a reason why it would not be able to compress these test signals. So I'm guessing the issue is more complex than it appears. One of the most interesting aspects of the MQA technology is perhaps the lossless band splitter/merger. I'd like to take a look at the patent in more detail to better understand what's going on there. Basically, they split the audio into two half-rate streams, and end up with one for the low end, and one for the high end. What I do not understand yet is how the high end could fit into half the sample rate. According to Shannon that would not fit? Possibly somebody read the whole thing already and can elaborate?

Would be a fun experiment: split an audio file in two by moving every odd-numbered sample to the second file. This would yield two files with half the sample rate that would play exactly the same (but are half a sample time-shifted). Now I could encode the second file with a lossy compression scheme (let's say constant bitrate Vorbis) and encode this in the lower bits of the first file. I could probably do some clever tricks to make up for some of the lost information there. Now I've made a poor mans MQA file, I'd call it VQA (Voodoo Quality Audio) . Eventually, reverse the process and see how well this works. There is probably a myriad of issues to solve to get this halfway working.

 

[Hayabusa]

What? I go to Tidal to get music. Instead, I would be fed very nasty sounding test tones that could damage tweeters and cause amplifiers to massively oscillate. I call that garbage from service providers point of view. Again, it is no different than you downloading an App that says it is a calculator but instead, tries to sell you bitcoin on the side. One complaint and it would be removed from those app stores.

You know better. These nasty sounding tones are the whole basis for your measurements and the existence of "Audio Science" and this website. They should be sacret to you They are beautifull mathematical constructs. I agree they are not music though.

 

[amirm]

Still, what was wrong with the files, for ‘someone’ to complain? What did happen - how were they taken advantage of?

The files he submitted broke the encoder and it generated errors. Ergo, the output was wrong even if the content were to be allowed.

Tidal/publisher were taken advantage of because they did not agree to be the encoding platform for some benchmarking/measurement. Clearly once they found out they didn't want to have to do with this subterfuge and nuked the content.

How were the GoldenOne’s files different from >this< (https://tidal.com/album/29581889)?

This is proper commercial content that says what it is. It doesn't claim to be music and then spit out completely different animal. No one misrepresented what it was so it is fine.

I just can't fathom continued questioning on this. GoldenEye by his own admission cheated and pretended to be publishing music when he had no intention whatsoever to a) distribute music or b) created music that anyone would want to consume. You think anyone should play such tricks on other company's real business with no consequences? Give me an example of where this kind of cheating is OK. Can your doctor for example secretly put you in a drug trial without your consent? Can Ford sell you a car with experimental firmware someone in the assembly line put in there to see what happens to the car when you drive it?

 

[amirm]

You know better. These nasty sounding tones are the whole basis for your measurements and the existence of "Audio Science" and this website.

I do know better and have explained why it is totally inappropriate to test MQA with test tones. Codecs are designed with certain assumptions. You can't violate them. A voice codec for example is created to encode voice. You can try to encode music with it and complain that it doesn't sound good but folks that know better would just laugh at you.

The *science* of lossy codecs says you use music and controlled listening tests to evaluate them. It also says learn what the technology does and then test it the way it should. A music codec is a music codec. It is not designed to spit out full range ultrasonics when such content doesn't exist in any music whatsoever.

 

[JohnYang1997]

I do know better and have explained why it is totally inappropriate to test MQA with test tones. Codecs are designed with certain assumptions. You can't violate them. A voice codec for example is created to encode voice. You can try to encode music with it and complain that it doesn't sound good but folks that know better would just laugh at you.

The *science* of lossy codecs says you use music and controlled listening tests to evaluate them. It also says learn what the technology does and then test it the way it should. A music codec is a music codec. It is not designed to spit out full range ultrasonics when such content doesn't exist in any music whatsoever.

Is MQA lossless to the CD quality?

 

[amirm]

They are beautifull mathematical constructs. I agree they are not music though.

There is also great beauty in taking advantage of the statistical characteristics of music to come up with a much more efficient way to store bits than with PCM. Yeh, statistics are much harder to understand but that is what is needed to participate in this topic and analyze MQA. Take a shortcut and you get beat up by people who know what is what.