Stereo signal encoding method and apparatus using a residual signal encoding parameter

Patent metadata

Field	Value
Publication number	US-12374345-B2
Application number	US-202418625538-A
Country	US
Kind code	B2
Filing date	Apr 3, 2024
Priority date	May 31, 2018
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

A stereo signal encoding method includes: obtaining a residual signal encoding parameter of a current frame of a stereo signal based on downmixed signal energy and residual signal energy of each of M sub-bands of the current frame, where the residual signal encoding parameter indicates whether to encode residual signals of the M sub-bands; determining whether to encode the residual signals based on the residual signal encoding parameter; and encoding the residual signals when it is determined that the residual signals need to be encoded.

First claim

The invention claimed is:

1. A method comprising:
obtaining M first downmixed signal energies of M first sub-bands of a current frame of a stereo signal, wherein M is an integer greater than 1;
obtaining M first residual signal energies of the M first sub-bands;
obtaining, based on the M first downmixed signal energies and the M first residual signal energies, a first parameter represented as res_dmx_ratio;
obtaining, based on the M first downmixed signal energies and the M first residual signal energies, a second parameter represented as frame_nrg_ratio;
obtaining a first residual signal encoding parameter of the current frame according to the following formula:
res_dmx_ratio_lt=res_dmx_ratio·α+res_dmx_ratio_lt_prev·(1−α),

wherein res_dmx_ratio_lt represents the first residual signal encoding parameter, wherein res_dmx_ratio_lt_prev represents a second residual signal encoding parameter of a previous frame, wherein 0<α<1, and wherein when frame_nrg_ratio is greater than 3.2, a first value of α when res_dmx_ratio is less than 0.1 is greater than a second value of α when res_dmx_ratio is greater than or equal to 0.1;
determining, based on the first residual signal encoding parameter, whether to encode residual signals of the current frame;
encoding the residual signals when determining to encode the residual signals; and
avoiding encoding the residual signals when determining not to encode the residual signals.

2. The method of claim 1 , wherein res_dmx_ratio indicates a relationship between a downmixed signal energy of each of the M first sub-bands and a residual signal energy of each of the M first sub-bands.

3. The method of claim 1 , wherein frame_nrg_ratio indicates a relationship between a first energy sum and a second energy sum, wherein the first energy sum is a sum of the M first residual signal energies and the M first downmixed signal energies, wherein the second energy sum is a sum of M second residual signal energies of M second sub-bands of the previous frame and M second downmixed signal energies of the M second sub-bands, and wherein the M first sub-bands have same sub-band index numbers as the M second sub-bands.

4. The method of claim 1 , wherein determining to encode residual signals of the current frame comprises:
comparing the first residual signal encoding parameter with a preset first threshold that is greater than zero and less than 1; and
determining to encode the residual signals when the first residual signal encoding parameter is greater than the preset first threshold.

5. The method of claim 1 , wherein the current frame includes N sub-bands that comprise the M first sub-bands, wherein M<N, wherein M and N are positive integers, and wherein N is greater than 1.

6. The method of claim 5 , wherein the M first sub-bands have first sub-band indexes that are less than a preset maximum sub-band index number.

7. The method of claim 6 , further comprising:
comparing second sub-band indexes of the N sub-bands; and
obtaining the M first sub-bands based on comparing the second sub-band indexes of the N sub-bands.

8. An apparatus comprising:
a memory configured to store programming instructions; and
a processor coupled to the memory and configured to execute the programming instructions to cause the apparatus to:
obtain M first downmixed signal energies of M first sub-bands of a current frame of a stereo signal, wherein M is an integer greater than 1;
obtain M first residual signal energies of the M first sub-bands;
obtain, based on the M first downmixed signal energies and the M first residual signal energies, a first parameter represented as res_dmx_ratio;
obtain, based on the M first downmixed signal energies and the M first residual signal energies, a second parameter represented as frame_nrg_ratio;
obtain a first residual signal encoding parameter of the current frame according to the following formula:

res_dmx
⁢
_ratio
⁢
_lt

=

res_dmx
⁢

_ratio
·
α

+

res_dmx
⁢
_ratio
⁢
_lt
⁢

_prev
·

(

1
-
α

)

,

 wherein res_dmx_ratio_lt represents the first residual signal encoding parameter, wherein res_dmx_ratio_lt_prev represents a second residual signal encoding parameter of a previous frame, wherein 0<α<1, and when frame_nrg_ratio is greater than 3.2, a first value of α when res_dmx_ratio is less than 0.1 is greater than a second value of α when res_dmx_ratio is greater than or equal to 0.1;

determine, based on the first residual signal encoding parameter, whether to encode residual signals of the current frame;
encode the residual signals when determining to encode the residual signals; and
avoid encoding the residual signals when determining not to encode the residual signals.

9. The apparatus of claim 8 , wherein res_dmx_ratio indicates a relationship between a downmixed signal energy of each of the M first sub-bands and a residual signal energy of each of the M first sub-bands.

10. The apparatus of claim 8 , wherein the second parameter indicates a relationship between a first energy sum and a second energy sum, wherein the first energy sum is a sum of the M first residual signal energies and the M first downmixed signal energies, wherein the second energy sum is a sum of M second residual signal energies of M second sub-bands of the previous frame and M second downmixed signal energies of the M second sub-bands, and wherein the M first sub-bands have same sub-band index numbers as the M second sub-bands.

11. The apparatus of claim 8 , wherein the programming instructions that, when executed by the processor, further cause the apparatus to:
compare the first residual signal encoding parameter with a preset first threshold that is greater than zero and less than 1; and
determine to encode the residual signals when the first residual signal encoding parameter is greater than the preset first threshold.

12. The apparatus of claim 8 , wherein the current frame includes N sub-bands that comprise the M first sub-bands, wherein M<N, wherein M and N are positive integers, wherein N is greater than 1, wherein the M first sub-bands have first sub-band indexes that are less than a preset maximum sub-band index number.

13. The apparatus of claim 12 , wherein the programming instructions that, when executed by the processor, further cause the apparatus to:
compare second sub-band indexes of the N sub-bands; and
obtain the M first sub-bands based on comparing the second sub-band indexes of the N sub-bands.

14. A non-transitory computer-readable medium configured to store instructions that, when executed by a processor, caus

Assignees

• Huawei Tech Co Ltd

Inventors

• Wang Bin
• Liu Zexin
• Li Haiting

Classifications

• H04L65/75

  Media network packet handling · CPC title

• H04L65/756

  adapting media to device capabilities · CPC title

• H04L65/70

  Media network packetisation · CPC title

• H04S2400/03

  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) · CPC title

• H04S1/007

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