Stereo signal processing method and apparatus

Patent metadata

Field	Value
Publication number	US-12230283-B2
Application number	US-202318449281-A
Country	US
Kind code	B2
Filing date	Aug 14, 2023
Priority date	May 16, 2017
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

A stereo signal processing method includes performing delay estimation on a stereo signal of a current frame to determine an inter-channel time difference of the current frame, identifying a sign of the inter-channel time difference of the current frame is different from a sign of an inter-channel time difference of a previous frame of the current frame, performing delay alignment processing on the first-channel signal of the current frame based on the inter-channel time difference of the current frame, and performing delay alignment processing on the second-channel signal of the current frame based on the inter-channel time difference of the previous frame.

First claim

What is claimed is:

1. A method comprising:
obtaining a pulse-code modulation (PCM) audio signal;
obtaining a first inter-channel time difference (ITD) of a current frame based on the PCM audio signal, wherein the first ITD is a time difference between a first-channel signal of the current frame and a second-channel signal of the current frame, and wherein a first sign of the first ITD is either a positive sign or a negative sign;
performing, when the first sign is different from a second sign of a second ITD of a previous frame adjacent to the current frame, a first delay alignment processing on the first-channel signal based on the first ITD to obtain a third signal;
performing, when the first sign is different from the second sign, a second delay alignment processing on the second-channel signal based on the second ITD to obtain a fourth signal;
performing a mid/side (M/S) downmix processing on the third signal and the fourth signal to obtain a fifth signal and a sixth signal; and
encoding the fifth signal and the sixth signal.

2. The method of claim 1 , wherein performing the first delay alignment processing on the first-channel signal comprises compressing a first processing length signal in the first-channel signal into a first alignment processing length signal in order to obtain the third signal.

3. The method of claim 2 , further comprising obtaining a first processing length based on the first ITD and a first alignment processing length, wherein the first processing length is greater than the first alignment processing length.

4. The method of claim 3 , wherein the first processing length is a first sum of an absolute value of the first ITD and the first alignment processing length.

5. The method of claim 4 , wherein a first start point of the first processing length signal is located before a second start point of the first alignment processing length signal, and a first length between the first start point and the second start point is the absolute value of the first ITD, or
wherein the second start point is located at a third start point of the first-channel signal or after the third start point, and a second length between the second start point and an end point of the first-channel signal is greater than or equal to the first alignment processing length, or
wherein the second start point is located before the third start point, a third length between the second start point and the third start point is less than or equal to a transition section length, the second length is greater than or equal to a second sum of the first alignment processing length and the transition section length, and the transition section length is less than or equal to the absolute value of the first ITD.

6. The method of claim 1 , wherein performing the second delay alignment processing on the second-channel signal comprises stretching a second processing length signal of a second processing length in the second-channel signal into a second alignment processing length signal of a second alignment processing length in order to obtain the fourth signal.

7. The method of claim 6 , further comprising obtaining the second processing length based on the second ITD and the second alignment processing length, wherein the second processing length is less than the second alignment processing length.

8. The method of claim 7 , wherein the second processing length is a difference between the second alignment processing length and an absolute value of the second ITD.

9. The method of claim 8 , wherein a first start point of the second processing length signal is located after a second start point of the second alignment processing length signal, and a first length between the first start point and the second start point is the absolute value of the second ITD, or
wherein the second start point is located at a third start point of the second-channel signal or after the third start point, and a second length between the second start point and an end point of the second-channel signal is greater than or equal to the second alignment processing length.

10. An apparatus comprising:
one or more memories configured to store programming instructions; and
one or more processors coupled to the one or more memories and configured to execute the programming instructions to cause the apparatus to:
obtain a pulse code modulation (PCM) audio signal;
obtain a first inter-channel time difference (ITD) of a current frame based on the PCM audio signal, wherein the first ITD is a time difference between a first-channel signal of the current frame and a second-channel signal of the current frame, and wherein a first sign of the first ITD is either a positive sign or a negative sign;
perform, when the first sign is different from a second sign of a second ITD of a previous frame adjacent to the current frame, a first delay alignment processing on the first-channel signal based on the first ITD to obtain a third signal;
perform, when the first sign is different from the second sign, a second delay alignment processing on the second-channel signal based on the second ITD to obtain a fourth signal;
perform a mid/side (M/S) downmix processing on the third signal and the fourth signal to obtain a fifth signal and a sixth signal; and
encode the fifth signal and the sixth signal.

11. The apparatus of claim 10 , wherein the one or more processors are further configured to execute the programming instructions to cause the apparatus to perform the first delay alignment processing on the first-channel signal by compressing a first processing length signal in the first-channel signal into a first alignment processing length signal in order to obtain the third signal.

12. The apparatus of claim 11 , wherein the one or more processors are further configured to execute the programming instructions to cause the apparatus to obtain a first processing length based on the first ITD and a first alignment processing length, and wherein the first processing length is greater than the first alignment processing length.

13. The apparatus of claim 12 , wherein the first processing length is a first sum of an absolute value of the first ITD and the first alignment processing length.

14. The apparatus of claim 13 , wherein a first start point of the first processing length signal is located before a second start point of the first alignment processing length signal, and a first length between the first start point and the second start point is the absolute value of the first ITD, or
wherein the second start point is located at a third start point of the first-channel signal or after the third start point, and a second length between the second start point and an end point of the first-channel signal is greater than or equal to the first alignment processing length, or
wherein the second start point is located before the third start point, a third length between the second start point and the third start point is less than or equal to a transition section length, the second length is greater than or equal to a second sum of the first alignment processing length and the transition section length, and the transition section length is less than or equal to the absolute value of the first ITD.

15. The apparatus of claim 10 , wherein the one or more processors are further configured to execute the programming instructions to cause the apparatus to perform the second delay alignment processing on the second-channel signal by stretching a second processing length signal of a second processing length in the second-channel signal into a second alignment processing length signal of a sec

Assignees

• Huawei Tech Co Ltd

Inventors

• Shlomot Eyal
• Li Haiting
• Miao Lei

Classifications

• H04S2420/03

  Application of parametric coding in stereophonic audio systems · CPC title

• H04S1/007

  in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02) · 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

• G10L19/008 Primary

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title