# US 2019/0318751 A1 · Methods and apparatus for encoding and decoding multi-channel hoa audio signals

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2019/0318751 A1
- Document ID: US20190318751A1
- Status: Published application
- Kind: A1
- Application number: 16/417,480
- Filed: 2019-05-20
- Published: 2019-10-17
- Earliest claimed: 2012-07-16
- Assignees: Dolby Laboratories Licensing Corporation
- Applicants: Dolby Laboratories Licensing Corporation
- Inventors: Johannes BOEHM; Sven KORDON; Alexander KRUEGER; Peter JAX
- Web page: https://patentgrep.com/patent/US20190318751A1

## CPC

- G10L 19/012: Comfort noise or silence coding
- G10L 19/008: Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
- G10L 19/0212: {using orthogonal transformation}
- G10L 19/038: Vector quantisation, e.g. TwinVQ audio
- 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 2420/11: Application of ambisonics in stereophonic audio systems
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- H04S: STEREOPHONIC SYSTEMS

## Abstract

The present invention is directed to apparatus and methods for decoding Higher Order Ambisonics (HOA) audio signals. HOA audio signals may be decompressed based on perceptual decoding to determine at least an HOA representation corresponding to the HOA audio signals. A rotated transform may be determined based on a rotation of a spherical sample grid. A rotated HOA representation may be determined based on the rotated transform and the HOA representation. The rotated HOA representation may be rendered to output to a loudspeaker setup.

## Claims

### Claim 1

A method for decoding Higher Order Ambisonics (HOA) audio signals, the method comprising:
decompressing the HOA audio signals based on perceptual decoding to determine at least an HOA representation corresponding to the HOA audio signals;
determining a rotated transform based on a rotation of a spherical sample grid;
determining a rotated HOA representation based on the rotated transform and the HOA representation; and
rendering the rotated HOA representation to output to a loudspeaker setup.

### Claim 2

An apparatus for decoding Higher Order Ambisonics (HOA) audio signals, the apparatus comprising:
a decoder configured to:
decompress the HOA audio signals based on perceptual decoding to determine HOA representations corresponding to the HOA audio signals;
determine a rotated transform based on a rotation of a spherical sample grid;
determine a rotated HOA representation based on the rotated transform and the HOA representation; and
a renderer configured to render the rotated HOA representation to output to a loudspeaker setup.

### Claim 3 (depends on 1)

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