These aspects include but are not limited to whether the audio signal processing improves or degrades the sound quality, whether the lossy audio compression degrades the sound quality, the utility of the authentication function, and the effect of licensing fees on music recording and playback businesses.
The press launch of MQA was held in December 2014 in London,[3] followed by the company hosting a demonstration room at the Consumer Electronics Show in Las Vegas in January 2015.
[13] In May 2021, the Apple Music streaming service announced a Lossless Audio pricing tier, which was described as a "death knell" for MQA.
The technology supports both MQA and PCM audio up to stereo 384 kHz, with the encoded data rate able to be scaled seamlessly from 20 Mbit/s to below 200 kbit/s.
[23] As of 24 July 2024, Tidal streaming service dropped support of MQA in favor of PCM-FLAC, a lossless and open source format.
[24] On 1 January 2025, it was reported that Lenbrook plans to create a new streaming service which will offer only MQA-encoded music and it is expected to be launched in May of 2025.
[25] MQA encoding is lossy;[26][27] it hierarchically compresses the relatively little energy in the higher frequency bands into data streams that are embedded in the lower frequency bands using proprietary dithering techniques, allowing for an apparent reduction in sample rate and hence file size.
[30] MQA-encoded audio can be contained with file formats such as FLAC, ALAC or CD-DA; hence, it can be played back on systems either with or without an MQA decoder.
[31] Other than the sampling and convolution methods, which were not explained by MQA in detail, the encoding process is similar to that used in XRCD and HDCD.
In addition to the compressed audio data, the codec also carries meta-data for authentication and playback filter control.
The authentication meta-data instructs the decoder that the file contains MQA format and identifies basic or "Studio" certification which may be indicated on the playback device.
[36] Robert Harley, editor of The Absolute Sound stated in March 2016 that MQA "will forever change the way we and future generations consider digital audio".
[37] John Atkinson, editor of Stereophile stated the following about the launch of MQA in December 2014 "In almost 40 years of attending audio press events, only rarely have I come away feeling that I was present at the birth of a new world.
[40] Similarly, when Universal Music Group announced in February 2017 that they would be selling songs in MQA format, company executive Michael Nash stated "with MQA, we are working with a partner whose technology is among the best solutions for streaming high-res audio, and one that doesn't ask music fans to compromise on sound quality for convenience".
[41] An article titled "Digital Done Wrong" on the International Audio/Video Review website concluded that MQA is founded on a fundamentally unsound understanding of correct digital audio processing and found that playback of a sample MQA encoding demonstrated gross distortion and reconstruction failure.
"[47] In an interview for online publication Positive Feedback, engineer Andreas Koch is critical of MQA due to its lossy algorithms and compression, along with its licensing requirements; also saying that a format such as this "does not solve any problem that the world currently has.
While the encoding system remains proprietary, work by Måns Rullgård was able to examine the control stream after the first decoding step through analysis of the Bluesound "rendering" firmware in early 2017 with published code.
[58] To counter the points made by Goldensounds, Jim Austin of Stereophile published an article which included criticism of the use of test signals which violated the MQA encoder parameters that are designed for music, and stating that the "GoldenSound's tests are a missed opportunity" and that the "critique is unfair".