MQA software decoding in Roon

And here’s why. The more we bug the Roon team about this kind of stuff the less they will share.

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MQA started out being pitched as the new cake, then the new icing and In reality it seems that MQA’s real value-proposition is as a cherry on top of the particular cake and icing that you already love. Software decoding gets you 99%+ of that cherry (i.e. 24/96), without a costly spend to get it or losing the downstream benefits of room correction, DSP or filters already optimized for your digital front-end and system overall.

As has been said already, potentially the biggest benefit is to the streaming companies in reduced file size and therefore cost to stream hires audio files.

Russ

As an IT guy (software developer) I don’t understand how you suddenly can pack substantially more information into a lossless file-format. Either flac is a shitty implementation/specification, or something fishy is going on.

And there are supposed to be 2 unfolds, which means the audio information needed is 4 times more.

It’s not lossless - no one has ever claimed it was. It is lossless up to 20 kHz or so, then it only encodes actual content above (i.e., no noise or digital silence).

Also, it can encode normal Redbook content (i.e., no “folds”), 88.2 / 96 content (one “fold”), 176.4 / 192 content (two “folds”), or 352.8 / 384 content (four “folds”) - or higher, I believe, though I scarcely believe there would be any audible content at that bitrate.

Hi Magnus

This was originally discussed as far back as Dec 15

Cheers
Tom

The simplest answer is that the classical specs are indeed horribly inefficient. It is a rectangular format: in a 24/192 file, it allocates the full 24-bit resolution all the way up to 192 kHz, and you certainly do not have any full-volume signal at 192 kHz, and you don’t have any meaningful signal in the least significant bit at 192 kHz either. By discarding these unused portions of the signal space, the transmission is lossy in a data transmission sense, i.e. you can’t recreate the signal including random noise in the bottom bit. But since these portions of the signal space are unused, discarding them can be lossless from an audio perspective.

The complete story is more complex, but this is the simplest answer to your specific question about signaling efficiency.

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Cheers for the answer, I am not an audio-tech guy so I don’t know exactly how the audio is D/A and A/D converted. But the ‘192 khz’ is sample rate right, and not the maximum frequency sent to the amplifier? And 24 bit is the resolution of the amplitude for a frequency? Or is 192 khz both sample rate and maximum frequency?

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192k is the sample rate, by classical theory it can transmit half of that frequency, or 96k.

As discussed here and there, we want that not because we can hear that far but because of other improvements it gives to the sound, directly and indirectly.

But the rectangular data space was always a ridiculously inefficient way of transmitting that.

Although some people get hung up on the word “lossy”, equating it to the Antichrist.

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It’s a good bet that MQA uses non-Shannon sampling (information from adjacent sampling periods convolved with a kernel, and reversible) which means that the information density per nominal sample is greater than that from conventional regular sampling.

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Reading that made my head hurt! But it sounds fishy :slight_smile:

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http://www.aes.org/e-lib/download.cfm/17501.pdf?ID=17501

Section 4.

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Thanks for (re)posting the link Joel. The Stuart/Craven MQA AES paper makes a bit more sense now than when I read it a year ago.

Do you have any predictions as to when Roon will be able to unpack via software the first part of MQA files?

when its done

No need to rush it IMHO

I’d like it. Then my comments regarding MQA would be less theoretical.

So this is my first time in Roon and I’m loving it so far. I previously tried amarra luxe and though sounded great, horrible ui. I did notice though that when I’d play a master album such as Ed Sheeran’s Divide on Amarra it would end up being a higher sample rate than Roon on my Chord Mojo. Other master albums seem to work fine; it’s just a handful of albums that show up as 44.1 in Roon. Any thoughts on the different sample rates!

Roon doesn’t yet decode MQA so rates will always be displayed as 48/24 or in a few cases 41/24 which is the bit rate of the originating MQA file. Amarra does a ‘first unfold’ so partially decodes the MQA file. We think Roon will have the same capability as Amarra soon for those Master files.

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That was February 10th of this (now rapidly ending) year.
Are you trying to sit this one out? :roll_eyes:

Don’t get me wrong, MQA for me personally is pretty close to scam and I need MQA like a second opening on my backside and I wish MQA would vanish faster than it was built up.
Imagine what could have been done with those marketing millions wasted to convince people of MQA :rage:
But obviously it is still a topic for many and communication on this matter was “silent”…

My biggest wish is that the record companies DON’T turn their whole catalog into MQA and only offer MQA material for Streaming. That would definitely end my Streaming endeavers and I would exclusively go back to my local Music.