[clpetersen]

MQA does have a small number of patents (4) assigned to them, so there may be some intrinsic value if the techniques themselves have any merit. Lenbrook thinks so.


Discrete dither
Patent number: 11095304
Abstract: Quantisation methods are provided which employ dither techniques to reduce the noise penalty in certain circumstances whilst still removing noise modulation. One method relates to reducing the wordwidth of audio by one bit, while another method relates to burying one bit of data in a pair of signal samples.
Type: Grant
Filed: December 18, 2019
Date of Patent: August 17, 2021
Assignee: MQA Limited
Inventors: Peter Graham Craven, Malcolm Law

Lossless bandsplitting and bandjoining using allpass filters
Patent number: 10896683
Abstract: Methods and devices are described for lossless bandsplitting and bandjoining of streams of signal samples using allpass filtering. The bandsplitting operation reformats an original stream into two intermediate streams representing even and odd samples of the original stream, and then matrix filters these to provide two output substreams representing higher frequency components and lower frequency components of the original stream. Conversely, the bandjoining operation matrix filters two subband streams to provide two quantised intermediate substreams, and then interleaves the filtered streams to furnish an output stream, such that the intermediate substreams are the even and odd samples of the output stream.
Type: Grant
Filed: December 21, 2016
Date of Patent: January 19, 2021
Assignee: MQA Limited
Inventors: Peter Graham Craven, Malcolm Law

Digital encapsulation of audio signals
Patent number: 10867614
Abstract: Encoding and decoding systems are described for the provision of high quality digital representations of audio signals with particular attention to the correct perceptual rendering of fast transients at modest sample rates. This is achieved by optimising downsampling and upsampling filters to minimise the length of the impulse response while adequately attenuating alias products that have been found perceptually harmful.
Type: Grant
Filed: October 2, 2018
Date of Patent: December 15, 2020
Assignee: MQA Limited
Inventors: Peter Graham Craven, John Robert Stuart

Transparent lossless audio watermarking enhancement
Patent number: 10811017
Abstract: Methods and devices are described for losslessly watermarking an audio signal by performing a noise shaped quantisation and clipping the output from the noise shaped quantisation to bounds computed by a pair of quantised linear functions with gradient 0.5 of the input to the noise shaped quantisation. Corresponding methods and devices are also described for inverting the process to recover an exact replica of the original audio signal.
Type: Grant
Filed: December 22, 2016
Date of Patent: October 20, 2020
Assignee: MQA Limited
Inventor: Malcolm Law