Qualcomm Patent | Higher order ambisonics signal compression

Patent: Higher order ambisonics signal compression

Publication Number: 10176814

Publication Date: 2019-01-08

Applicants: Qualcomm

Abstract

Systems and techniques for compression and decoding of audio data are generally disclosed. An example device for compressing higher order ambisonic (HOA) coefficients representative of a soundfield includes a memory configured to store audio data and one or more processors configured to: determine when to use ambient HOA coefficients of the HOA coefficients to augment one or more foreground audio objects obtained through decomposition of the HOA coefficients based on one or more singular values also obtained through the decomposition of the HOA coefficients, the ambient HOA coefficients representative of an ambient component of the soundfield.

Background

A higher-order ambisonics (HOA) signal (often represented by a plurality of spherical harmonic coefficients (SHC) or other hierarchical elements) is a three-dimensional representation of a soundfield. The HOA or SHC representation may represent the soundfield in a manner that is independent of the local speaker geometry used to playback a multi-channel audio signal rendered from the SHC signal. The SHC signal may also facilitate backwards compatibility as the SHC signal may be rendered to well-known and highly adopted multi-channel formats, such as a 5.1 audio channel format or a 7.1 audio channel format. The SHC representation may therefore enable a better representation of a soundfield that also accommodates backward compatibility.

Summary

In general, techniques are described for higher order ambisonics (HOA) compression. In various examples, the techniques are based one or more of energies (or energy values) associated with audio objects, and on bit allocation mechanisms.

In one aspect, a method of compressing higher order ambisonic (HOA) coefficients representative of a soundfield includes determining when to use ambient HOA coefficients of the HOA coefficients to augment one or more foreground audio objects obtained through decomposition of the HOA coefficients based on one or more singular values also obtained through the decomposition of the HOA coefficients, the ambient HOA coefficients representative of an ambient component of the soundfield.

In another aspect, a method of decoding encoded decoding encoded higher order ambisonics (HOA) coefficients representative of a soundfield includes allocating bits to an audio object of the soundfield, based on an energy associated with the audio object, the audio object being obtained through decomposition of the encoded HOA coefficients.

In another aspect, a device for compressing higher order ambisonic (HOA) coefficients representative of a soundfield includes a memory configured to store audio data and one or more processors configured to: determine when to use ambient HOA coefficients of the HOA coefficients to augment one or more foreground audio objects obtained through decomposition of the HOA coefficients based on one or more singular values also obtained through the decomposition of the HOA coefficients, the ambient HOA coefficients representative of an ambient component of the soundfield.

In another aspect, a device for compressing higher order ambisonic (HOA) coefficients representative of a soundfield, the device includes means for determining when to use ambient HOA coefficients of the HOA coefficients to augment one or more foreground audio objects obtained through decomposition of the HOA coefficients based on one or more singular values also obtained through the decomposition of the HOA coefficients, the ambient HOA coefficients representative of an ambient component of the soundfield.

The details of one or more aspects of the techniques are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques will be apparent from the description and drawings, and from the claims.