Why is everyone so down on MQA?


Ok. MQA is a little bit complicated to understand without doing a little research. First of all: MQA is not technically a lossy format. The way it works is very unique. The original master tape (Holy grail of SQ) is folded or compressed into a smaller format. It is later unfolded through a process I don’t claim to understand. The fully processed final version is lossless! It is the song version from the original master tape. FYI, original master tapes are usually the best sounding, they are also the truest version of any song- they are painstakingly produced along with the artist in the studio during the recording process. Ask anyone, they are the real deal. For some reason most people hate the sound quality! One caveat, the folding/unfolding process is usually carried out at one time by a dac. But some dacs only compress and do not unfold….I think Meridian should explain dac/ streamer compatibility issue. When your hardware supports the single step the sound quality is pretty amazing. They should have explained in more detail what the format is all about.

walkenfan2013

Showing 3 responses by fair

People are mostly down on MQA because:

(A) Tidal encoded significant number of 44/16, that is, CD-quality files, with MQA. This was not a smart move, because compression inherent in MQA took its toll on a format that wasn’t highly resolving to start with.

(B) MQA is a proprietary lossy DRM-enabled format. This adds friction to its use, as one needs to have a compatible streamer to fully unlock the MQA data. Moreover, MQA licensing cost naturally makes such streamers more expensive.

MQA’s sweet spot would be streaming of 192/24 and 384/24 files. Compression could be beneficial for the provider’s expenditures on bandwidth, loss of sound quality would be imperceptible, and pirating of essentially full-resolution studio masters would be inhibited.

@painter24

MQA was not really a solution for a problem that didn't exist; to my mind, it was a thinly veiled, cynical attempt to ring fence and monopolise the streaming market. It was never about giving the end user a superior listening experience.

MQA solves two problems:

(1) High bandwidth costs. A streaming provider has to either eat the significantly increased expenditures (~6.5x for 192/24 PCM/FLAC as compared to 44/16 PCM/FLAC), or to start charging customers significantly more and thus lose market share.

In places like US, Europe, South Korea, Japan, this may appear to be an insignificant concern, because streaming subscription is relatively inexpensive in comparison to average incomes. In some other countries, things are different. 

(2) Pirating. In countries such as China and India pirating of music is still a big concern. MQA mitigates this issue: without full MQA decoding a pirate will only get a diminished, lower-quality version of a master.

Also, I would not be surprised to learn that MQA uses watermarking, extending to decoded analog signal, which could enable tracing of pirated copies. That would explain stubborn refusal of MQA people to provide their encoding device for non-commercial testing. 

 

@dalims4

From the very same Web page:

"... our encoders remove the audible ‘digital blur’ that builds up in studio production."

"But a lossless file is just a digital container ..."

So, they modify the digital master first, and then losslessly pack the changed data.

The papers explaining how MQA works claim that there is no perceptual loss. However, technically there is data loss, because original signal gets compressed: they call it "folding", yet it doesn't change general nature of the process.

Moreover, it appears that a signal's digital representation can only be perceptually transparently folded into MQA format if it fits into prescribed triangle on energy vs frequency graph. The energy of higher frequency components has to be below descending line defined in MQA specification.

Correspondingly, experiments with publishing music on Tidal in MQA format uncovered two types of losses: additional noise slightly beyond what mere dithering would add, and rather significant artifacts triggered by signals not fitting into the MQA triangle.

So, like any competently designed compressed format, MQA strives to be perceptually transparent on signals falling within its domain of applicability. Which, arguably, are the most music signals. And in this sense, it appears that there shall be no meaningful losses for most signals.

However, MQA can't be technically called a lossless PCM compression format, because a lossless format has to encode and then decode any PCM file with a supported bit depth and sampling rate in a bit-perfect manner. FLAC is an example of such format. Yet its compression factor isn't high - typically around 2x.

Correspondingly yet again, subjective evaluations of MQA-encoded recordings are mixed. Most files do indeed appear to be encoded in a perceptually transparent manner while being significantly smaller than FLAC. Others reportedly do not. If MQA was consistently the home run it claims to be, we wouldn't be having this conversation.