MQA Discussion

radioactive said:
What do you mean by "SW decoded"? I thought there aren't any SW decoders, rather you're just getting an "unfolded" FLAC.

I think I have a case that may be "SW decoded" but I'm not sure what's gong on. When I play an Depeche Mode "A Broken Frame" via the Tidal Program (on my CAPS PIPELINE which is connected to my DCS Debussy over USB), it unfolds as 24/96. But, when I use Roon and play back the same album (I made sure it was the same album by adding it to my favorites and the only other copy they have shows as 16/44) it unfolds as 24/48. Can someone explain?
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Status update on Roon vs Tidal desktop app:

Tidal desktop app in Exclusive Mode and Force Volume can software decode / unfold Tidal MQA music from 24/44 or 24/48 to 24/88 or 24/96 respectively, as case B here:
http://www.computeraudiophile.com/content/748-mqa-civilians/

The very latest Roon updates - if all components are updated to build 208 or later - provides access to "Masters" section of MQA albums (similar to the recent addition to Lumin app) but at this moment Roon does not perform any MQA decoding (case A). However, Roon Labs have said they'll provide MQA Core Decoding (case B, just like Tidal desktop app) at some point in the future.
 
rbbert said:
The U.S patent application for MQA is online at the US Patent Office website. Sorry I do not have a link, and it's not filed under "MQA". You will have to search for Robert Stuart under authors. Briefly, though, the philosophy underpinning MQA is that if the timing and phase characteristics of the original ADC can be mimiced in the DAC, the resulting sound will be "better" than if they are not. So far, almost every audio reviewer who has expressed an opinion agrees that the sound is better than with other digital formats.
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Thank you for information, Rob. If I can understand that is timing and mimice for this case, picture will clearer, probably.
 
FYI. computeraudiophile member abrxx has posted links to some patents in mid-January.
 
rbbert said:
The U.S patent application for MQA is online at the US Patent Office website. Sorry I do not have a link, and it's not filed under "MQA". You will have to search for Robert Stuart under authors. Briefly, though, the philosophy underpinning MQA is that if the timing and phase characteristics of the original ADC can be mimiced in the DAC, the resulting sound will be "better" than if they are not. So far, almost every audio reviewer who has expressed an opinion agrees that the sound is better than with other digital formats.
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I found same patent (as I think) https://patentscope.wipo.int/search...tring=nano OR filter OR ceramic&maxRec=599628

Also http://www.mqa.co.uk/customer/how-it-works

May be I miss something there, but looks like MQA is compression algorithm only without any compensation of ADC.
 
That patent description is (purposefully?) vague about the "time-invariant filtering", but in many discussions Bob Stuart has posted, he describes that in the way I mentioned earlier in the thread. Also the patent description does claim a "lossless" codec if the full encoding and decoding is used, as well as full use of the "time-invariant filtering" in that situation.
 
Pretty clear it's lossy without full unfold. But described as 'benign' in 'audiophile circles' (Bottom of patent Description page).
Well now...
 
rbbert said:
That patent description is (purposefully?) vague about the "time-invariant filtering", but in many discussions Bob Stuart has posted, he describes that in the way I mentioned earlier in the thread. Also the patent description does claim a "lossless" codec if the full encoding and decoding is used, as well as full use of the "time-invariant filtering" in that situation.
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May be I miss something, but looks like time-invariant filter is any traditional digital filter (as FIR as IIR) by this definition https://ccrma.stanford.edu/~jos/filters/Time_Invariant_Filters.html

It is filter with unchanged time shift between input and output.

I suppose, "lossless" here have own definition (not binary identical source and decoded data).
 
I agree completely with your skepticism about MQA. As highresaudio's post points out, some of the biggest problems with MQA are that it is proprietary and that Meridian has not been very forthcoming about the technical aspects of the process which are supposedly responsible for "better" sound. "Watermarking" is also not a popular technology from a consumer standpoint.
 
Rob,

Now audiophiles more like get master, me seems.

For big multiuser systems MQA can give significant transmitting band economy.

I only doubt about claimed (by some people) improving of sound quality after conversion to MQA format.
 
YuriKorzunov said:
I only doubt about claimed (by some people) improving of sound quality after conversion to MQA format.
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Actually, that's the part I don't doubt.
The key is, "some" people. Some people will prefer it, think it "better", others not. That's what preference is all about!
As long as no one starts insisting their preference is absolute...
Of course, that is exactly what some audiophiles will do.

cheers,

AJ
 
AJ Soundfield said:
Actually, that's the part I don't doubt.
The key is, "some" people. Some people will prefer it, think it "better", others not. That's what preference is all about!
As long as no one starts insisting their preference is absolute...
Of course, that is exactly what some audiophiles will do.
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AJ,

I written "doubt", because MQA is lossy (officially by MQA site link above). Here may be matter: "lossy" is audible or not.

But "lossy" is not better, by my definition of sound quality as "more quality is lesser distortions".

Some kinds of distortions may cause "more nice" sound, but me seems, MQA cause other kind of distortions. I read about a "lazy" filter.

As example, some filter can cause inaudible distortions. But without the filter sound can't be worse. Except some cases, that not related to considered compression method.

I think, what improving of sound quality may be due some impelentations of MQA playback devices, but not format as itself.
 
http://www.digitalaudioreview.net/2...calls-for-a-deeper-technical-analysis-of-mqa/

"On the day after Valentine’s Day, Kerestedjian was no longer in love with Bob Stuart and Peter Craven’s music technology. His primary concern was one of quality control. The MQA incoming files couldn’t be analysed – their hi-res content remained unverifiable. The labels had to be trusted not to provide up-sampled content as hi-res masters but Kerestedjian’s pre-MQA experience said otherwise. His secondary concern: a perceived lack of promotional support from the MQA mothership."
 
Mike said:
http://www.digitalaudioreview.net/2...calls-for-a-deeper-technical-analysis-of-mqa/

"On the day after Valentine’s Day, Kerestedjian was no longer in love with Bob Stuart and Peter Craven’s music technology. His primary concern was one of quality control. The MQA incoming files couldn’t be analysed – their hi-res content remained unverifiable. The labels had to be trusted not to provide up-sampled content as hi-res masters but Kerestedjian’s pre-MQA experience said otherwise. His secondary concern: a perceived lack of promotional support from the MQA mothership."
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Interesting read Mike.
 
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