Method and apparatus for allocating bits of audio signal

1. A method for allocating bits of an audio signal comprising:

dividing a frequency band of a frame of an audio signal into a plurality of sub-bands;

obtaining a quantized normalization factor of each of the plurality of sub-bands;

dividing the plurality of sub-bands into multiple groups;

acquiring an average of quantized normalization factors of each of the multiple groups, wherein the average of the quantized normalization factors of each of the multiple groups is acquired based on the quantized normalization factors of all sub-bands in the group;

calculating differences of the acquired average of the quantized normalization factors of each of the multiple groups;

determining, according to the calculated differences of the acquired average of the quantized normalization factors of each of the multiple groups, which one of two bit allocation algorithms is to be used for bit allocation;

allocating, according to the determined bit allocation algorithm, number of allocated bits of each of the multiple groups;

adjusting the number of allocated bits of each of the multiple groups; and

allocating the adjusted number of allocated bits for the group to sub-bands in the group.

2. The method according to claim 1 , wherein adjusting the number of allocated bits for each of the multiple groups is performed using a saturation algorithm.

3. The method according to claim 2 , wherein adjusting, the number of allocated bits for each of the multiple groups comprises:

obtaining a number of saturation bits of each of the multiple groups;

determining a bit-saturated group and a number of surplus bits in the bit-saturated group according to the number of saturation bits of the bit-saturated group and the number of allocated bits of the bit-saturated group, wherein the number of allocated bits of the bit-saturated group is greater than the number of saturation bits of the bit-saturated group, and wherein the number of the surplus bits in the bit-saturated group is a difference between the number of allocated bits of the bit-saturated group and the number of saturation bits of the bit-saturated group; and

allocating, based on a predefined algorithm, the surplus bits to at least one of the multiple groups.

4. The method according to claim 1 , wherein one of the two bit allocation algorithms is a weighting algorithm, and wherein the other of the two bit allocation algorithms is not a weighting algorithm.

5. The method according to claim 1 , wherein there are three of the multiple groups.

6. The method according to claim 1 , wherein the quantized normalization factor is obtained as follows:

obtaining a normalization factor of each of the plurality of sub-bands; and

quantizing the obtained normalization factor of each of the plurality of sub-bands.

7. The method according to claim 1 , wherein the normalization factor is obtained according to:

Norm

⁡

(

p

)

=

1

L

p

⁢

∑

k

=

s

p

e

p

⁢

y

⁡

(

k

)

2

,

p

=

0

,

…

⁢

,

P

-

1

,

wherein Norm(p) denotes the normalization factor of sub-band p, L p denotes a number of coefficients of sub-band p, s p denotes a start point of sub-band p, e p denotes an end point sub-band p, P denotes a number of the plurality of sub-bands, and y(k) denotes a k th coefficient of sub-band p.

8. The method according to claim 1 , wherein the sub-bands in the group are consecutive.

9. The method according to claim 8 , wherein the average of quantized normalization factors of the group is acquired according to:

group_avg

=

group_wnorm

E

-

S

+

1

,

wherein group_avg denotes the average of quantized normalization factors of the group, E denotes an index of an end sub-band of the group, S denotes an index of a start sub-band of the group, and group_wnorm denotes a sum of quantized normalization factors of all sub-bands in the group and is acquired according to:

group_wnorm

=

∑

b

=

S

E

⁢

wnorm

⁡

[

b

]

,

and

wherein wnorm[b] denotes the quantized normalization factor of a b th sub-band in the group.

10. An apparatus for allocating bits of an audio signal comprising:

a memory for storing processor-executable instructions; and

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

dividing a frequency band of a frame of an audio signal into a plurality of sub-bands;

obtaining a quantized normalization factor of each of the plurality of sub-bands;

dividing the plurality of sub-bands into multiple groups;

acquiring an average of quantized normalization factors of each of the multiple groups, wherein the average of the quantized normalization factors of each of the multiple groups is acquired based on the quantized normalization factors of all sub-bands in the group;

calculating differences of the acquired average of the quantized normalization factors of each of the multiple groups;

determining, according to the calculated differences of the acquired average of the quantized normalization factors of each of the multiple groups, which one of two bit allocation algorithms is to be used for bit allocation;

allocating, according to the determined bit allocation algorithm, a number of allocated bits of each of the multiple groups;

adjusting the number of allocated bits of each of the multiple groups; and

allocating the adjusted number of allocated bits for the group to sub-bands in the group.

11. The apparatus according to claim 10 , wherein adjusting the number of allocated bits for each of the multiple groups is performed by using a saturation algorithm.

12. The apparatus according to claim 11 , wherein the processor is further configured to execute the processor-executable instructions to facilitate the following steps:

obtaining a number of saturation bits of each of the multiple groups;

determining a bit-saturated group and a number of surplus bits in the bit-saturated group according to the number of saturation bits of the bit-saturated group and the number of allocated bits of the bit-saturated group, wherein the number of allocated bits of the bit-saturated group is greater than the number of saturation bits of the bit-saturated group, and wherein the number of the surplus bits in the bit-saturated group is a difference between the number of allocated bits of the bit-saturated group and the number of saturation bits of the bit-saturated group; and

allocating, based on a predefined algorithm, the surplus bits to at least one of the multiple groups.

13. The apparatus according to claim 10 , wherein one of the two bit allocation algorithms is a weighting algorithm, and wherein the other of the bit allocation algorithms is not a weighting algorithm.

14. The apparatus according to claim 10 , wherein there are three of the multiple groups.

15. The apparatus according to claim 10 , wherein the processor is further configured to execute the processor-executable instructions to facilitate the following:

obtaining a normalization factor of each of the plurality of sub-bands; and

quantizing the obtained normalization factor of each of the plurality of sub-bands.

16. The apparatus according to claim 15 , wherein the normalization factor is obtained according to:

Norm

⁡

(

p

)

=

1

L

p

⁢

∑

k

=

s

p

e

p

⁢

y

⁡

(

k

)

2

,

p

=

0

,

…

⁢

,

P

-

1

,

and

wherein Norm(p) denotes the normalization factor of sub-band p, L p denotes a number of coefficients of sub-band p, s p denotes a start point of sub-band p, e p denotes an end point sub-band p, P denotes a number of the plurality of sub-bands, and y(k) denotes a k th coefficient of sub-band p.

17. The apparatus according to claim 10 , wherein the sub-bands in the group are consecutive.

18. The apparatus according to claim 17 , wherein the average of quantized normalization factors of the group is acquired according to:

group_avg

=

group_wnorm

E

-

S

+

1

,

wherein group_avg denotes the average of quantized normalization factors of the group, E denotes an index of an end sub-band of the group, S denotes a index of a start sub-band of the group, and group_wnorm denotes a sum of quantized normalization factors of all sub-bands in the group and acquired according to:

group_wnorm

=

∑

b

=

S

E

⁢

wnorm

⁡

[

b

]

,

wherein wnorm[b] denotes the quantized normalization factor of a b th sub-band in the group.

19. A non-transitory computer readable storage medium, tangibly embodying computer program code, which, when executed by a computer unit, causes the computer unit to perform a method comprising:

dividing a frequency band of a frame of an audio signal into a plurality of sub-bands;

obtaining a quantized normalization factor of each of the plurality of sub-bands;

dividing the plurality of sub-bands into multiple groups;

acquiring an average of quantized normalization factors of each of the multiple groups, wherein the average of the quantized normalization factors of each of the multiple groups is acquired based on the quantized normalization factors of all sub-bands in the group;

calculating differences of the acquired average of the quantized normalization factors of each of the multiple groups;

determining, according to the calculated differences of the acquired average of the quantized normalization factors of each of the multiple groups, which one of two bit allocation algorithms is to be used for bit allocation;

allocating, according to the determined bit allocation algorithm, a number of allocated bits of each of the multiple groups;

adjusting the number of allocated bits of each of the multiple groups; and

allocating the adjusted number of allocated bits for the group to sub-bands in the group.

20. The non-transitory computer readable storage medium according to claim 19 , wherein adjusting, based on the number of allocated bits for each of the multiple groups, the number of allocated bits for each of the multiple groups comprises:

obtaining a number of saturation bits of each of the multiple groups;

determining a bit-saturated group and a number of surplus bits in the bit-saturated group according to the number of saturation bits of the bit-saturated group and the number of allocated bits of the bit-saturated group, wherein the number of allocated bits of the bit-saturated group is greater than the number of saturation bits of the bit-saturated group, and wherein the number of the surplus bits in the bit-saturated group is a difference between the number of allocated bits of the bit-saturated group and the number of saturation bits of the bit-saturated group; and

allocating, based on a predefined algorithm, the surplus bits to at least one of the multiple groups.