# US 12,225,368 B2 · Audio channel spatial translation

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- Number: US 12,225,368 B2
- Document ID: US12225368B2
- Status: Granted
- Kind: B2
- Application number: 18/474,170
- Filed: 2023-09-25
- Published: 2024-03-21
- Granted: 2025-02-11
- Earliest claimed: 2008-12-18
- Assignees: Dolby Laboratories Licensing Corporation
- Applicants: Dolby Laboratories Licensing Corporation
- Inventors: Mark F. Davis
- Web page: https://patentgrep.com/patent/US12225368B2

## CPC

- H04S 5/005: {of the pseudo five- or more-channel type, e.g. virtual surround}
- H04S 3/02: of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other
- H04S 2400/03: Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 (H04S2400/01 takes precedence)
- H04S: STEREOPHONIC SYSTEMS

## Abstract

The present invention is directed to methods and apparatus for translating a first plurality of audio input channels to a second plurality of audio output channels. This includes determining that there is pair-wise coding among any of the first plurality of audio input channels, determining an input/output-mapping matrix for mapping at least a first set of the first plurality of audio input channels to at least a second set of the second plurality of audio output channels; and deriving the second plurality of audio output channels based on first plurality of audio input channels, the input/output-mapping matrix and the determined pair-wise coding. The first plurality of audio input channels represent the same soundfield represented by the second plurality of audio output channels.

## Claims

### Claim 1

A method for translating a first plurality of audio input channels to a second plurality of audio output channels, the method comprising:
receiving, by an audio processor decoder module, the first plurality of audio input channels;
determining an input/output-mapping matrix for mapping at least a first set of the first plurality of audio input channels to at least a second set of the second plurality of audio output channels, wherein the input/output-mapping matrix is a mixing matrix, wherein each matrix element of the input/output-mapping matrix is a transfer function relating to mapping an input channel i of the first plurality of audio input channels to an output channel j of the second plurality of audio output channels; and
deriving the second plurality of audio output channels based on the first plurality of audio input channels and the input/output-mapping matrix,
wherein at least one coefficient of the input/output-mapping matrix is computed based at least in part on a cross-correlation of pair-wise coded audio input signals,
wherein the cross-correlation is based at least in part on a cross power value for the pair-wise coded audio input signals,
wherein the deriving of the second plurality of audio output channels based on first plurality of audio input channels causes a soundfield represented by the first plurality of audio input channels to be determined and reproduced, and
wherein the first plurality of audio input channels represents a same soundfield represented by the second plurality of audio output channels;
wherein a total number of audio input channels in the first plurality of audio input channels equals a total number of audio output channels in the second plurality of audio output channels.

### Claim 2 (depends on 1)

A non-transitory computer readable storage medium containing instructions that when executed by a processor perform the method of claim 1.

### Claim 3

A system for translating a first plurality of audio input channels to a second plurality of audio output channels, the system comprising:
a receiver for receiving the first plurality of audio input channels;
a first processor for determining an input/output-mapping matrix for mapping at least a first set of the first plurality of audio input channels to at least a second set of the second plurality of audio output channels, wherein the input/output-mapping matrix is a mixing matrix, wherein each matrix element of the input/output-mapping matrix is a transfer function relating to mapping an input channel i of the first plurality of audio input channels to an output channel j of the second plurality of audio output channels; and
and a second processor for deriving the second plurality of audio output channels based on the first plurality of audio input channels and the input/output-mapping matrix,
wherein at least one coefficient of the input/output-mapping matrix is computed based at least in part on a cross-correlation of pair-wise coded audio input signals,
wherein the cross-correlation is based at least in part on a cross power value for the pair-wise coded audio input signals,
wherein the deriving of the second plurality of audio output channels based on first plurality of audio input channels causes a soundfield represented by the first plurality of audio input channels to be determined and reproduced, and
wherein the first plurality of audio input channels represents a same soundfield represented by the second plurality of audio output channels;
wherein a total number of audio input channels in the first plurality of audio input channels equals a total number of audio output channels in the second plurality of audio output channels.