Signal processing method and apparatus

1. An audio signal processing method, comprising:

allocating, according to a total number of available bits to be allocated, a quantity of primarily allocated bits for each of at least a portion of sub-bands of a frame of an audio signal, wherein a quantity of the portion of sub-bands is greater than two;

performing, according to the quantity of primarily allocated bits for each of the portion of the sub-bands, a pulse quantity determination operation for each of the portion of the sub-bands respectively, so as to obtain a quantity of surplus bits of the frame, wherein the surplus bits are a part of the available bits;

selecting, according to a secondary bit allocation parameter, two subbands for secondary bit allocation from the portion of the sub-bands, wherein the secondary bit allocation parameter comprises: an average quantity of primary bits per unit bandwidth of each sub-band of the portion of sub-bands, and a frequency range of each sub-band of the portion of sub-bands, wherein the average quantity of primary bits per unit bandwidth of the sub-band is determined according to the quantity of primarily allocated bits of the sub-band and bandwidth of the sub-band;

allocating, according to the quantity of the surplus bits, a quantity of secondarily allocated bits for each of the two sub-bands;

determining a quantity of pulses for each of the two sub-bands respectively according to the quantity of primarily allocated bits for each of the two sub-bands and the quantity of secondarily allocated bits for each of the two sub-bands; and

quantizing spectral coefficients for each of the two sub-bands according to the determined quantity of pulses for each of the two sub-bands.

2. The method according to claim 1 , wherein the secondary bit allocation parameter further comprises: a quantization state of a previous-frame sub-band corresponding to each sub-band of the portion of sub-band.

3. The method according to claim 1 , wherein the secondary bit allocation parameter further comprises:

a signal type of the signal of each sub-band of the portion of sub-band.

4. The method according to claim 3 , wherein the signal type of the signal of each sub-band of the portion of sub-band is either harmonic or non-harmonic.

5. The method according to claim 1 , wherein the two sub-bands selected for secondary bit allocation are successive in a frequency domain.

6. The method according to claim 1 , wherein the two sub-bands for secondary bit allocation are selected by:

determining a target sub-band set according to at least one of the quantity of surplus bits or the sub-band characteristic of the sub-band,

wherein the two sub-bands are selected from the target sub-band set, wherein each sub-band in the target sub-band set belongs to the frame.

7. The method according to claim 6 , wherein the target sub-band set is determined according to a sub-band characteristic of a sub-band in m first sub-band sets one-to-one correspondingly related to m predetermined conditions, wherein m is an integer greater than or equal to 1, and each sub-band in the m first sub-band sets belongs to the frame.

8. The method according to claim 7 , wherein

the target sub-band set corresponds to a set formed by sub-bands that belong to all the m first sub-band sets when all sub-band sets of the m first sub-band sets meet the corresponding predetermined conditions.

9. The method according to claim 7 , wherein the target sub-band set corresponds to a set formed by remaining sub-bands of the frame other than sub-bands that belong to all the m first sub-band sets when a sub-band set of the m first sub-band sets does not meet a corresponding predetermined condition.

10. The method according to claim 7 , wherein the target sub-band set corresponds to a set formed by all sub-bands in at least one sub-band set of the m first sub-band sets, each of the at least one sub-band set meeting a corresponding predetermined condition.

11. The method according to claim 7 , wherein the target sub-band set corresponds to a set formed by sub-bands of the frame that do not belong to any sub-band set of the m first sub-band sets when no sub-band set of the m first sub-band sets meets a corresponding predetermined condition.

12. The method according to claim 7 , wherein any predetermined condition of the m predetermined conditions comprises at least one of the following conditions:

that a coefficient-quantized sub-band exists in previous-frame sub-bands of a corresponding first sub-band set, that an average envelope value of sub-bands in the corresponding first sub-band set is greater than a first threshold, or that a sub-band carrying a signal of a harmonic type exists in the corresponding first sub-band set.

13. The method according to claim 7 , wherein a frequency of a sub-band in the m first sub-band sets is higher than a frequency of a sub-band not in the m first sub-band sets.

14. An audio signal processing apparatus, comprising:

a memory for storing processor-executable instructions; and

a processor operatively coupled to the memory, the processor being configured to execute the processor-executable instructions to facilitate the following steps:

allocate, according to a total number of bits to be allocated, a quantity of primarily allocated bits for at least a portion of sub-bands of a frame of an audio signal, wherein a quantity of the portion of sub-bands is greater than two;

perform, according to the quantity of primarily allocated bits for each of the portion of the sub-bands, a pulse quantity determination operation for each of the portion of the sub-bands respectively, so as to obtain a quantity of surplus bits of the frame, wherein the surplus bits are a part of the available bits;

select, according to a secondary bit allocation parameter, two subbands for secondary bit allocation from the portion of the sub-bands, wherein the secondary bit allocation parameter comprises: an average quantity of primary bits per unit bandwidth of each sub-band of the portion of sub-bands, and a frequency range of each sub-band of the portion of sub-bands, wherein the average quantity of primary bits per unit bandwidth of the sub-band is determined according to the quantity of primarily allocated bits of the sub-band and bandwidth of the sub-band;

allocate, according to the quantity of the surplus bits, a quantity of secondarily allocated bits for each of the two sub-bands;

determine a quantity of pulses for each of the two sub-bands respectively according to the quantity of primarily allocated bits for each of the two sub-bands and the quantity of secondarily allocated bits for each of the two sub-bands; and

quantize spectral coefficients for each of the two sub-bands according to the determined quantity of pulses for each of the two subbands.

15. The apparatus according to claim 14 , wherein the secondary bit allocation parameter further comprises: a quantization state of a previous-frame sub-band corresponding to each sub-band of the portion of sub-band.

16. The apparatus according to claim 14 , the secondary bit allocation parameter further comprises:

a signal type of the signal of each sub-band of the portion of sub-band.

17. The apparatus according to claim 16 , wherein the signal type of the signal of each sub-band of the portion of sub-band is either harmonic or non-harmonic.

18. The apparatus according to claim 14 , wherein the two sub-bands selected for secondary bit allocation are successive in a frequency domain.

19. The apparatus according to claim 14 , wherein the processor is further configured to execute the processor-executable instructions to facilitate the following:

determine a target sub-band set according to at least one of the quantity of surplus bits or the sub-band characteristic of the particular sub-band,

wherein the two sub-bands are selected from the target sub-band set, wherein each sub-band in the target sub-band set belongs to the frame.

20. The apparatus according to claim 19 , wherein the target sub-band set is determined according to a sub-band characteristic of a sub-band in m first sub-band sets one-to-one correspondingly related to m predetermined conditions, wherein m is an integer greater than or equal to 1, and each sub-band in the m first sub-band sets belongs to the frame.

21. The apparatus according to claim 20 , wherein the target sub-band set corresponds to a set formed by sub-bands that belong to all the m first sub-band sets when all sub-band sets of the m first sub-band sets meet the corresponding predetermined conditions.

22. The apparatus according to claim 20 , wherein the target sub-band set corresponds to a set formed by remaining sub-bands of the frame other than sub-bands that belong to all the m first sub-band sets when a sub-band set of the m first sub-band sets does not meet a corresponding predetermined condition.

23. The apparatus according to claim 20 , wherein the target sub-band set corresponds to a set formed by all sub-bands in at least one sub-band set of the m first sub-band sets, each of the at least one sub-band set meeting a corresponding predetermined condition.

24. The apparatus according to claim 20 , wherein the target sub-band set corresponds to a set formed by sub-bands of the frame that do not belong to any sub-band set of the m first sub-band sets when no sub-band set of the m first sub-band sets meets a corresponding predetermined condition.

25. The apparatus according to claim 20 , wherein any predetermined condition of the m predetermined conditions comprises at least one of the following conditions:

that a coefficient-quantized sub-band exists in previous-frame sub-bands of a corresponding first sub-band set, that an average envelope value of sub-bands in the corresponding first sub-band set is greater than a first threshold, or that a sub-band carrying a signal of a harmonic type exists in the corresponding first sub-band set.

26. The apparatus according to claim 20 , wherein a frequency of a sub-band in the m first sub-band sets is higher than a frequency of a sub-band not in the m first sub-band sets.