Reference

Sidebar 5: Glossary

ADC (A/D Converter): Analog to Digital Converter.

DAC (D/A Converter): Digital to Analog Converter.

Encapsulation: The process which identifies and secures the information space of a music signal and which exploits advanced sampling and reconstruction methods to optimise analogue end-to-end temporal precision while minimising data rate. We refer to the encapsulated object as the 'kernel.'

Hierarchical Coding: A conceptual framework that models analogue as an infinite sample rate, finite word-size representation which can be approximated by a hierarchical chain of downward and upward splines. In MQA the transmission kernel is not a sinc function, nor is it Gaussian, it is informed by neuroscience.

MQA can also employ the hierarchical packing system—so-called 'Music Origami.' When the packing is folding a 'kernel,' the process is losslessly reversible.

Kernel: The encapsulated core music signal. The apparent sampling rate of the kernel we refer to as the 'transmission rate.'

Legacy: The Legacy quality audio is that provided by playback of the MQA distribution stream without a decoder. The perceived audio will be at least equivalent to a standard CD (44.1kHz, 16-bit) for a 1x transmission file.

MQA: MQA, Master Quality Authentication, provides a means to securely encode and transmit high resolution audio. An MQA decoder may be used to verify the authenticity of the audio and to present a high resolution listening experience. A listener may still playback and listen to the encoded audio stream without an MQA decoder, treating it as a standard PCM stream, at CD quality.

Rates: Original, Kernel, Transmission, Transport, Render: The hierarchical system can present different apparent sample rates throughout the process. We refer to 'original' (studio capture), 'transmission' (information rate of the kernel), 'transport' (the apparent speed of the file) and 'rendering' (the rate sent to the DAC).

Rendering: The MQA Renderer performs sampling reconstruction under instruction from the encoder while matching and optimising the attached DAC to deliver an authenticated analogue output. The renderer may replace or over-ride reconstruction filters in the DAC. The renderer may perform cross-family conversion depending on the platform.

1x, 2x, 4x, etc.: We refer to sample rates by their multipliers. These represent multiples of the basis sampling frequency of 44,100Hz or 48,000Hz, yielding two families of sample rate. For example, in the 44.1kHz family, 2x audio refers to an 88.2kHz sample rate, whereas in the 48kHz family, 2x refers to a 96kHz sample rate. Consumer decoders are not required to support 50.4, 64 or 128kHz.