Method for encoding multi-channel signal and encoder

1. A method for encoding a multi-channel signal, comprising:

obtaining a multi-channel signal of a current frame;

determining an initial inter-channel time difference (ITD) value of the current frame;

controlling, based on characteristic information of the multi-channel signal, a quantity of target frames allowed to appear continuously, wherein the characteristic information comprises at least one of a signal-to-noise ratio of the multi-channel signal or a peak feature of cross correlation coefficients of the multi-channel signal, and wherein an ITD value of a previous frame of a target frame is reused as an ITD value of the target frame;

determining an ITD value of the current frame based on the initial ITD value of the current frame and the quantity of target frames allowed to appear continuously; and

encoding the multi-channel signal based on the ITD value of the current frame.

2. The method of claim 1 , wherein before controlling the quantity of target frames allowed to appear continuously, the method further comprises determining the peak feature of the cross correlation coefficients of the multi-channel signal based on amplitude of a peak value of the cross correlation coefficients of the multi-channel signal and an index of a peak position of the cross correlation coefficients of the multi-channel signal.

3. The method of claim 2 , wherein determining the peak feature of the cross correlation coefficients of the multi-channel signal comprises:

determining a peak amplitude confidence parameter based on the amplitude of the peak value of the cross correlation coefficients of the multi-channel signal, wherein the peak amplitude confidence parameter represents a confidence level of the amplitude of the peak value of the cross correlation coefficients of the multi-channel signal;

determining a peak position fluctuation parameter based on an ITD value corresponding to the index of the peak position of the cross correlation coefficients of the multi-channel signal and an ITD value of a previous frame of the current frame, wherein the peak position fluctuation parameter represents a difference between the ITD value corresponding to the index of the peak position of the cross correlation coefficients of the multi-channel signal and the ITD value of the previous frame of the current frame; and

determining the peak feature of the cross correlation coefficients of the multi-channel signal based on the peak amplitude confidence parameter and the peak position fluctuation parameter.

4. The method of claim 3 , wherein determining the peak amplitude confidence parameter comprises determining, as the peak amplitude confidence parameter, a ratio of a difference between an amplitude value of the peak value of the cross correlation coefficients of the multi-channel signal and an amplitude value of a second largest value of the cross correlation coefficients of the multi-channel signal to the amplitude value of the peak value of the cross correlation coefficients of the multi-channel signal.

5. The method of claim 3 , wherein determining the peak position fluctuation parameter comprises determining, as the peak position fluctuation parameter, an absolute value of a difference between the ITD value corresponding to the index of the peak position of the cross correlation coefficients of the multi-channel signal and the ITD value of the previous frame of the current frame.

6. The method of claim 1 , wherein controlling, the quantity of the target frames allowed to appear continuously comprises:

controlling, based on the peak feature of the cross correlation coefficients of the multi-channel signal, the quantity of the target frames allowed to appear continuously; and

reducing, by adjusting at least one of a target frame count or a threshold of the target frame count, the quantity of the target frames allowed to appear continuously when the peak feature of the cross correlation coefficients of the multi-channel signal meets a preset condition, wherein the target frame count represents a quantity of target frames that have currently appeared continuously, and wherein the threshold of the target frame count indicates the quantity of the target frames allowed to appear continuously.

7. The method of claim 6 , wherein controlling the quantity of the target frames allowed to appear continuously comprises controlling, based on the peak feature of the cross correlation coefficients of the multi-channel signal, the quantity of the target frames allowed to appear continuously only when the signal-to-noise ratio of the multi-channel signal does not meet a preset signal-to-noise ratio condition, and wherein the method further comprises stopping reusing an ITD value of a previous frame of the current frame as the ITD value of the current frame when the signal-to-noise ratio of the multi-channel signal meets the preset signal-to-noise ratio condition.

8. The method of claim 1 , wherein controlling the quantity of the target frames allowed to appear continuously comprises:

determining whether the signal-to-noise ratio of the multi-channel signal meets a preset signal-to-noise ratio condition;

controlling, based on the peak feature of the cross correlation coefficients of the multi-channel signal, the quantity of the target frames allowed to appear continuously when the signal-to-noise ratio of the multi-channel signal does not meet the preset signal-to-noise ratio condition; and

stopping reusing an ITD value of a previous frame of the current frame as the ITD value of the current frame when the signal-to-noise ratio of the multi-channel signal meets the preset signal-to-noise ratio condition.

9. The method of claim 8 , wherein stopping reusing the ITD value of the previous frame of the current frame as the ITD value of the current frame comprises increasing a target frame count such that a value of the target frame count is greater than or equal to a threshold of the target frame count, wherein the target frame count represents a quantity of target frames that have currently appeared continuously, and wherein the threshold of the target frame count indicates the quantity of the target frames allowed to appear continuously.

10. An encoder, comprising:

a memory comprising instructions; and

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

obtain a multi-channel signal of a current frame;

determine an initial inter-channel time difference (ITD) value of the current frame;

control, based on characteristic information of the multi-channel signal, a quantity of target frames allowed to appear continuously, wherein the characteristic information comprises at least one of a signal-to-noise ratio of the multi-channel signal or a peak feature of cross correlation coefficients of the multi-channel signal, and wherein an ITD value of a previous frame of a target frame is reused as an ITD value of the target frame;

determine an ITD value of the current frame based on the initial ITD value of the current frame and the quantity of target frames allowed to appear continuously; and

encode the multi-channel signal based on the ITD value of the current frame.

11. The encoder of claim 10 , wherein the instructions further cause the processor to be configured to determine the peak feature of the cross correlation coefficients of the multi-channel signal based on amplitude of a peak value of the cross correlation coefficients of the multi-channel signal and an index of a peak position of the cross correlation coefficients of the multi-channel signal.

12. The encoder of claim 11 , wherein the instructions further cause the processor to be configured to:

determine a peak amplitude confidence parameter based on the amplitude of the peak value of the cross correlation coefficients of the multi-channel signal, wherein the peak amplitude confidence parameter represents a confidence level of the amplitude of the peak value of the cross correlation coefficients of the multi-channel signal;

determine a peak position fluctuation parameter based on an ITD value corresponding to the index of the peak position of the cross correlation coefficients of the multi-channel signal and an ITD value of a previous frame of the current frame, wherein the peak position fluctuation parameter represents a difference between the ITD value corresponding to the index of the peak position of the cross correlation coefficients of the multi-channel signal and the ITD value of the previous frame of the current frame; and

determine the peak feature of the cross correlation coefficients of the multi-channel signal based on the peak amplitude confidence parameter and the peak position fluctuation parameter.

13. The encoder of claim 12 , wherein the instructions further cause the processor to be configured to determine, as the peak amplitude confidence parameter, a ratio of a difference between an amplitude value of the peak value of the cross correlation coefficients of the multi-channel signal and an amplitude value of a second largest value of the cross correlation coefficients of the multi-channel signal to the amplitude value of the peak value of the cross correlation coefficients of the multi-channel signal.

14. The encoder of claim 13 , wherein the instructions further cause the processor to be configured to determine, as the peak position fluctuation parameter, an absolute value of a difference between the ITD value corresponding to the index of the peak position of the cross correlation coefficients of the multi-channel signal and the ITD value of the previous frame of the current frame.

15. The encoder of claim 10 , wherein the instructions further cause the processor to be configured to:

control, based on the peak feature of the cross correlation coefficients of the multi-channel signal, the quantity of the target frames allowed to appear continuously; and

reduce, by adjusting at least one of a target frame count or a threshold of the target frame count, the quantity of the target frames allowed to appear continuously when the peak feature of the cross correlation coefficients of the multi-channel signal meets a preset condition, wherein the target frame count represents a quantity of target frames that have currently appeared continuously, and wherein the threshold of the target frame count indicates the quantity of the target frames allowed to appear continuously.

16. The encoder of claim 15 , wherein the instructions further cause the processor to be configured to:

control, based on the peak feature of the cross correlation coefficients of the multi-channel signal, the quantity of the target frames allowed to appear continuously only when the signal-to-noise ratio of the multi-channel signal does not meet a preset signal-to-noise ratio condition; and

stop reusing an ITD value of a previous frame of the current frame as the ITD value of the current frame when the signal-to-noise ratio of the multi-channel signal meets the preset signal-to-noise ratio condition.

17. The encoder of claim 10 , wherein the instructions further cause the processor to be configured to:

determine whether the signal-to-noise ratio of the multi-channel signal meets a preset signal-to-noise ratio condition;

control, based on the peak feature of the cross correlation coefficients of the multi-channel signal, the quantity of the target frames allowed to appear continuously when the signal-to-noise ratio of the multi-channel signal does not meet the preset signal-to-noise ratio condition; and

stop reusing an ITD value of a previous frame of the current frame as the ITD value of the current frame when the signal-to-noise ratio of the multi-channel signal meets the preset signal-to-noise ratio condition.

18. The encoder of claim 17 , wherein the instructions further cause the processor to be configured to increase a target frame count such that a value of the target frame count is greater than or equal to a threshold of the target frame count, wherein the target frame count represents a quantity of target frames that have currently appeared continuously, and wherein the threshold of the target frame count indicates the quantity of the target frames allowed to appear continuously.

19. The encoder of claim 10 , wherein the instructions further cause the processor to be configured to determine the ITD value of the current frame based on the initial ITD value of the current frame, a target frame count, and a threshold of the target frame count, wherein the target frame count represents a quantity of target frames that have currently appeared continuously, and wherein the threshold of the target frame count indicates the quantity of the target frames allowed to appear continuously.

20. The encoder of claim 10 , wherein the signal-to-noise ratio is a modified segmental signal-to-noise ratio of the multi-channel signal.