Stereo signal encoding method and apparatus

1. A method comprising:

determining a downmixed audio signal of a current frame;

determining a first residual audio signal of the current frame;

determining an energy relationship between the downmixed audio signal of the current frame and the residual audio signal of the current frame;

determining an initial encoding mode of the current frame based on the energy relationship;

obtaining indication information of a first encoding mode of the first residual audio signal of the current frame, wherein the first encoding mode indicates whether to encode the first residual audio signal or to not encode the first residual audio signal, and wherein the indication information comprises at least one of an encoding status of one or more second residual audio signals of one of more first previous frames of the current frame, a first value of an updating manner flag for a long-term smooth parameter of a first stereo audio signal of the current frame, or a second value of a status change parameter of the first stereo audio signal relative to one or more second stereo audio signals of the one or more first previous frames of the current frame;

determining the first encoding mode based on the indication information and the initial encoding mode; and

selectively performing encoding of the first residual audio signal according to the first encoding mode.

2. The method of claim 1 , wherein the encoding status indicates at least one of:

a first quantity of first consecutive frames previous to the current frame, wherein residual audio signals of all of the first consecutive frames are encoded;

a second quantity of second consecutive frames previous to the current frame, wherein residual audio signals of all of the second consecutive frames are not encoded; or

encoding modes of residual audio signals of N frames previous to the current frame, wherein the N frames are consecutive in a time domain, and wherein N is a positive integer.

3. The method of claim 2 , wherein the encoding status indicates the encoding modes, and wherein the method further comprises determining that the first encoding mode is the initial encoding mode when the initial encoding mode is the same as a second encoding mode of the one or more second residual audio signals of the one or more first previous frames.

4. The method of claim 2 , wherein the indication information comprises the encoding status or the first value, wherein the encoding status indicates the first quantity and the encoding modes, wherein the method further comprises determining that the first encoding mode is a second encoding mode of the one or more second residual audio signals when the initial encoding mode is different from the second encoding mode, wherein the second encoding mode indicates to encode the one or more second residual audio signals and that a first condition is met, and wherein the first condition comprises at least one of:

the first quantity is less than a first threshold;

the first value is zero; or

the second encoding mode is not modified.

5. The method of claim 2 , wherein the indication information comprises the encoding status or the second value, wherein the encoding status indicates the second quantity and the encoding modes, wherein the method further comprises determining that the first encoding mode is a second encoding mode of the one or more second residual audio signals when the initial encoding mode is different from the second encoding mode, wherein the second encoding mode indicates not to encode the one or more second residual audio signals and that a second condition is met, and wherein the second condition comprises at least one of:

the second quantity is less than a first threshold; or

the second value is greater than or equal to a second threshold and less than or equal to a third threshold.

6. The method of claim 2 , further comprising modifying, subsequent to determining the first encoding mode, the first encoding mode based on the indication information.

7. The method of claim 6 , wherein the encoding status indicates the encoding modes, and wherein the method further comprises determining that the first encoding mode indicates to encode the first residual audio signal when the first encoding mode is different from a second encoding mode of the one or more second residual audio signals and the second encoding mode of the one or more second residual audio signals is not modified.

8. The method of claim 1 ,

wherein the one or more first previous frames are M frames previous to the current frame and are consecutive in a time domain, wherein the second value comprises a first ratio of a first energy of the first stereo audio signal to a second energy of the one or more second stereo audio signals, and wherein M is a positive integer; or

wherein the one or more first previous frames are S frames previous to the current frame and are consecutive in the time domain, wherein the second value comprises a second ratio of a first amplitude of the first stereo audio signal to a second amplitude of the one or more second stereo audio signals, and wherein S is a positive integer.

9. The method of claim 1 , wherein the initial encoding mode is different than the first encoding mode.

10. An apparatus comprising:

a memory configured to store computer-executable instructions; and

a processor coupled to the memory, wherein the computer-executable instructions cause the processor to be configured to:

determine a downmixed audio signal of a current frame;

determine a first residual audio signal of the current frame;

determine an energy relationship between the downmixed audio signal of the current frame and the first residual audio signal of the current frame;

determine an initial encoding mode of the current frame based on the energy relationship;

obtain indication information of a first encoding mode of the first residual audio signal of the current frame, wherein the first encoding mode indicates whether to encode the first residual audio signal or to not encode the first residual audio signal, and wherein the indication information comprises at least one of an encoding status of one or more second residual audio signals of one or more first previous frames of the current frame, a first value of an updating manner flag for a long-term smooth parameter of a first stereo audio signal of the current frame, or a second value of a status change parameter of the first stereo audio signal relative to one or more second stereo audio signals of the one or more first previous frames;

determine the first encoding mode based on the indication information and the initial encoding mode; and

selectively perform encoding of the first residual audio signal according to the first encoding mode.

11. The apparatus of claim 10 , wherein the encoding status indicates at least one of:

a first quantity of first consecutive frames previous to the current frame, wherein residual audio signals of all of the first consecutive frames are encoded;

a second quantity of second consecutive frames previous to the current frame, wherein residual audio signals of all of the second consecutive frames are not encoded; or

encoding modes of residual audio signals of N frames previous to the current frame, wherein the N frames are consecutive in a time domain and wherein N is a positive integer.

12. The apparatus of claim 11 , wherein the encoding status indicates the encoding modes, and wherein the computer-executable instructions further cause the processor to be configured to determine that the first encoding mode is the initial encoding mode when the initial encoding mode is the same as a second encoding mode of the one or more second residual audio signals.

13. The apparatus of claim 11 , wherein the indication information comprises the encoding status or the first value, wherein the encoding status indicates the first quantity and the encoding modes, wherein the computer-executable instructions further cause the processor to be configured to determine that the first encoding mode is a second encoding mode of the one or more second residual audio signals when the initial encoding mode is different from the second encoding mode, wherein the second encoding mode indicates to encode the one or more second residual audio signals and that a first condition is met, and wherein the first condition comprises at least one of:

the first quantity is less than a first threshold;

the first value is zero; or

the second encoding mode is not modified.

14. The apparatus of claim 11 , wherein the indication information comprises the encoding status or the second value, wherein the encoding status indicates the second quantity and the encoding modes, wherein the computer-executable instructions further cause the processor to be configured to determine that the first encoding mode is a second encoding mode of the one or more second residual audio signals when the initial encoding mode is different from the second mode, wherein the second encoding mode indicates not to encode the one or more second residual audio signals and that a second condition is met, and wherein the second condition comprises at least one of:

the second quantity is less than a first threshold; or

the second value is greater than or equal to a second threshold and less than or equal to a third threshold.

15. The apparatus of claim 11 , wherein the computer-executable instructions further cause the processor to be configured to modify, subsequent to determining the first encoding mode, the first encoding mode based on the indication information.

16. The apparatus of claim 15 , wherein the encoding status indicates the encoding modes, and wherein the computer-executable instructions further cause the processor to be configured to determine that the first encoding mode indicates to encode the first residual audio signal when the first encoding mode is different from a second encoding mode of the one or more second residual audio signals and the second encoding mode of the one or more second residual audio signals is not modified.

17. The apparatus of claim 10 ,

wherein the one or more first previous frames are M frames previous to the current frame and are consecutive in a time domain, wherein the second value comprises a first ratio of a first energy of the first stereo audio signal to a second energy of the second stereo audio signal, and wherein M is a positive integer; or

wherein the one or more first previous frames are S frames previous to the current frame and are consecutive in a time domain, wherein the second value comprises a second ratio of a first amplitude of the first stereo audio signal to a second amplitude of the second stereo audio signal, and wherein S is a positive integer.

18. The apparatus of claim 10 , wherein the initial encoding mode is different than the first encoding mode.

19. A computer program product comprising computer-executable instructions for storage on a non-transitory computer-readable storage medium that, when executed by a processor, cause an apparatus to:

determine a downmixed audio signal of a current frame;

determine a first residual audio signal of the current frame;

determine an energy relationship between the downmixed audio signal of the current frame and the first residual audio signal of the current frame;

determine an initial encoding mode of the current frame based on the energy relationship;

obtain indication information of a first encoding mode of the first residual audio signal of the current frame, wherein the encoding mode indicates whether to encode the first residual audio signal of the current frame or to not encode the first residual audio signal of the current frame, and wherein the indication information comprises at least one of an encoding status of one or more second residual audio signals of one or more first previous frames of the current frame, a first value of an updating manner flag for a long-term smooth parameter of a first stereo audio signal of the current frame, or a second value of a status change parameter of the first stereo audio signal relative to one or more second stereo audio signals of the one or more first previous frames; and

determine the first encoding mode based on the indication information and the initial encoding mode; and

selectively perform encoding of the first residual audio signal according to the first encoding mode.

20. The computer program product of claim 19 , wherein the encoding status indicates at least one of:

a first quantity of first consecutive frames previous to the current frame, wherein residual audio signals of all of the first consecutive frames are encoded;

a second quantity of second consecutive frames previous to the current frame, wherein residual audio signals of all of the second consecutive frames are not encoded; or

encoding modes of residual audio signals of N frames previous to the current frame, wherein the N frames are consecutive in a time domain, and wherein N is a positive integer.