MQA

MQA (Master Quality Authenticated) is a proprietary digital audio technology introduced in the 2010s by MQA, Inc., founded by Bob Stuart and others. It distributes audio in a PCM-compatible format and represents content above the base sampling rate through a process of encoding, folding, authentication, and decoding on the playback end. MQA can be encapsulated in containers such as FLAC and ALAC, and the file extension is typically determined by the outer container format.

The encoding process places information from higher frequency bands into the base PCM range as shaped, low-level data. Ordinary non-MQA players decode the file as standard PCM, while MQA-compatible software or hardware recognizes the control information, performs one or more “unfolding” operations, and renders the final output according to the device’s capabilities. Displayed output rates such as 88.2, 96, 176.4, or 192 kHz may involve reconstruction and upsampling processes and are not equivalent to linear PCM of the same specification stored directly within the file.

MQA is not a fully lossless high-resolution PCM compression in the traditional sense. Its fundamental bandwidth can be losslessly restored under specific conditions, but high-frequency folding and rendering involve lossy or parametric processing; Therefore, “encapsulated in FLAC” only indicates that the outer FLAC layer can losslessly preserve the MQA-encoded PCM samples; it does not prove that the file is fully sample-by-sample reversible relative to the pre-encoded high-sampling-rate master.

Certification indicators are used to show that the player has recognized a signature compliant with the MQA process and the associated source status. Different colors or text prompts are defined by specific applications and do not constitute a universal guarantee of the recording’s artistry, the quality of the master, or the source of the release. Files may lose certification after volume processing, resampling, or other modifications, even if the audible content does not change noticeably.

The playback chain can be divided into capabilities such as core decoding, subsequent unfolding, and DAC rendering. After the software completes certain steps, it can pass the expanded PCM to a standard DAC, while a full-featured decoding device processes additional metadata; unrecognized playback can still output basic audio. Determining the actual playback path requires examining the file identifier, player status, digital output limitations, and DAC display simultaneously—it cannot be determined by the container’s sample rate alone.