Multi-channel signal encoding method and encoder

Patent metadata

Field	Value
Publication number	US-12334084-B2
Application number	US-202418419794-A
Country	US
Kind code	B2
Filing date	Jan 23, 2024
Priority date	Aug 10, 2016
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

A multi-channel signal encoding method includes obtaining a multi-channel signal of a current frame; determining an initial multi-channel parameter of the current frame; determining a difference parameter based on the initial multi-channel parameter of the current frame and multi-channel parameters of previous K frames of the current frame, where the difference parameter represents a difference between the initial multi-channel parameter of the current frame and the multi-channel parameters of the previous K frames, and K is an integer greater than or equal to one; determining a multi-channel parameter of the current frame based on the difference parameter and a characteristic parameter of the current frame; and encoding the multi-channel signal based on the multi-channel parameter of the current frame.

First claim

What is claimed is:

1. A method performed by an audio encoder comprising a processor, wherein the method comprises:
obtaining a first multi-channel audio signal of a current frame originating from a microphone;
determining a first multi-channel parameter of the current frame, wherein the first multi-channel parameter comprises an initial inter-channel time difference (ITD) value of the current frame in a hybrid-domain and is based on the following formula:

ITD
=

arg
⁢

max
⁡
(

IDFT
⁡
(

L
i

(
f
)

⁢

R
i
*

(
f
)

❘
"\[LeftBracketingBar]"

L
i

(
f
)

⁢

R
i
*

(
f
)

❘
"\[RightBracketingBar]"

)

)

,

wherein ITD is the ITD value, wherein L i (f) represents a first frequency domain coefficient of a left-channel frequency-domain signal of the first multi-channel audio signal, wherein R * i (f) represents a conjugate of a second frequency domain coefficient of a right-channel frequency-domain signal of the first multi-channel audio signal, wherein argmax( ) is a maximum value from a plurality of values, and wherein IDFT() represents an inverse discrete Fourier transform operation;
determining a first difference parameter based on first differences between the first multi-channel parameter and second multi-channel parameters of previous K frames of the current frame, wherein K is an integer greater than or equal to 1;
determining a third multi-channel parameter of the current frame based on the first difference parameter and a characteristic parameter of the current frame; and
encoding, based on the third multi-channel parameter, the first multi-channel audio signal into a bitstream.

2. The method of claim 1 , further comprising further determining the third multi-channel parameter when the first difference parameter meets a first preset condition.

3. The method of claim 2 , wherein the first difference parameter is an absolute value of a second difference between the first multi-channel parameter and a fourth multi-channel parameter of a previous frame of the previous K frames, wherein the first preset condition is that the first difference parameter is greater than a preset first threshold or a product of the first multi-channel parameter and the fourth multi-channel parameter, wherein the first preset condition is that the first difference parameter is less than or equal to 0.

4. The method of claim 2 , further comprising further determining the third multi-channel parameter using a correlation parameter of the current frame, wherein the correlation parameter represents a degree of correlation between the current frame and a previous frame of the previous K frames.

5. The method of claim 4 , further comprising determining the correlation parameter based on a first target channel audio signal in the first multi-channel audio signal and a second target channel audio signal in a second multi-channel audio signal of the previous frame.

6. The method of claim 5 , further comprising further determining the correlation parameter based on a first frequency domain parameter of the first target channel audio signal and a second frequency domain parameter of the second target channel audio signal, wherein the first frequency domain parameter is at least one of a first frequency domain amplitude value of the first target channel audio signal or a first frequency domain coefficient of the first target channel audio signal, and wherein the second frequency domain parameter is at least one of a second frequency domain amplitude value of the second target channel audio signal or a second frequency domain coefficient of the second target channel audio signal.

7. The method of claim 4 , further comprising determining the correlation parameter based on a first pitch period of the current frame and a second pitch period of the previous frame.

8. The method of claim 2 , further comprising further determining the third multi-channel parameter using fourth multi-channel parameters of previous T frames of the current frame when the characteristic parameter meets a second preset condition, wherein T is an integer greater than or equal to 1.

9. The method of claim 8 , wherein determining the third multi-channel parameter further comprises:
determining the fourth multi-channel parameters as the third multi-channel parameter when T is equal to 1; or
determining the third multi-channel parameter based on a change trend of the fourth multi-channel parameters when T is greater than or equal to 2.

10. The method of claim 8 , wherein the characteristic parameter comprises at least one of a correlation parameter or a peak-to-average ratio parameter of the current frame, wherein the peak-to-average ratio parameter represents a peak-to-average ratio of a signal of at least one channel in the first multi-channel audio signal, and wherein the second preset condition is that the characteristic parameter is greater than a preset threshold.

11. An encoder, comprising:
a memory comprising instructions; and
a processor coupled to the memory and configured to execute the instructions to cause the encoder to:
obtain a first multi-channel audio signal of a current frame originating from a microphone;
determine a first multi-channel parameter of the current frame, wherein the first multi-channel parameter comprises an initial inter-channel time difference (ITD) value of the current frame in a hybrid-domain and is based on the following formula:

ITD
=

arg

Assignees

• Huawei Tech Co Ltd

Inventors

• Liu Zexin
• Zhang Xingtao
• Li Haiting
• Miao Lei

Classifications

• G10L19/032

  Quantisation or dequantisation of spectral components · CPC title

• G10L19/022

  Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring · CPC title

• G10L25/03

  characterised by the type of extracted parameters · CPC title

• H04S3/00

  Systems employing more than two channels, e.g. quadraphonic (H04S5/00, H04S7/00 take precedence) · CPC title

• H04S2420/01

  Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD] · CPC title