Signal processing method and device

• US 10,347,264 B2
• Filed: 11/30/2018
• Issued: 07/09/2019
• Est. Priority Date: 04/29/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wang, Bin, Miao, Lei, Liu, Zexin
• Primary Examiner(s): Saint Cyr, Leonard
• Application Number:
  US16/205,246
• Publication Number:
  US 20190108848A1
• Time in Patent Office: 221 Days
• Field of Search: 704500-504
• CPC Class Codes: G10L 19/002 Dynamic bit allocation for perceptual audio coders G10L19/032
• CPC Class Codes: G10L 19/02 using spectral analysis, e.g. transform vocoders or subband vocoders
• CPC Class Codes: G10L 19/0204 using subband decomposition

Abstract

Present disclosure provides a signal processing method and device. Spectral coefficients of a current frame of a frequency-domain audio signal are divided into N sub-bands. N is a positive integer greater than 1. According to an energy attribute and a spectral attribute of a first subset of the N sub-bands, whether to modify original envelope values of sub-bands in the first subset is determined. A frequency range of each of the M sub-bands in the first subset is lower than a frequency range of each of the K sub-bands. Based on a determination that the original envelope values of the M sub-bands need to be modified, the original envelope values of the M sub-bands are modified individually to obtain modified envelope values of the M sub-bands. Encoding bits are allocated to each of the N sub-bands according to the modified envelope values of the M sub-bands and original envelope values of the K sub-bands.

Claims

1. An audio signal processing method, comprising:

obtaining, by an audio signal encoder, spectral coefficients of a current frame of an audio signal, wherein each of N sub-bands of the current frame comprises at least one spectral coefficient, and N is a positive integer greater than 1;

obtaining, by the audio signal encoder, a total energy of M sub-bands of the N sub-bands, a total energy of K sub-bands of the N sub-bands, and an energy of a first sub-band, wherein the M sub-bands and the K sub-bands have no overlap, M and K are positive integers, and N=M+K, wherein the energy of the first sub-band is the largest among energies of the M sub-bands;

determining, by the audio signal encoder, whether to modify original envelope values of the M sub-bands based on a ratio of the total energy of the M sub-bands to the total energy of the K sub-bands and a ratio of the energy of the first sub-band to the total energy of the M sub-bands;

based on a determination that the original envelope values of the M sub-bands need to be modified, modifying, by the audio signal encoder, original envelope values of the M sub-bands individually to obtain modified envelope values of the M sub-bands, wherein the modified envelope values of the M sub-bands is one of determining factors for allocating encoding bits to the N sub-bands, and wherein each of the N sub-bands has either at least one encoding bit allocated or no encoding bit allocated;

quantizing, by the audio signal encoder, spectral coefficients of each sub-band that has at least one encoding bits allocated; and

writing, by the audio signal encoder, the quantized spectral coefficients into a bitstream.

2. The method according to claim 1, wherein when the ratio of the total energy of the M sub-bands to the total energy of the K sub-bands falls in a first range, and the ratio of the energy of the first sub-band to the total energy of the M sub-bands is no less than a threshold, it is determined to modify the original envelope values of the M sub-bands.

3. The method according to claim 2, wherein the first range is [⅙

, ⅔

].

4. The method according to claim 2, wherein when an encoded bandwidth of the audio signal is 0 to 4 KHz, the threshold is

5. The method according to claim 2, wherein when an encoded bandwidth of the audio signal is 0 to 8 KHz, the threshold is

6. The method according to claim 1, wherein modifying the original envelope values of the M sub-bands individually to obtain modified envelope values of the M sub-bands comprises:

determining, by the audio signal encoder, a modification factor for each of the M sub-bands according to the total energy of the M sub-bands and the energy of the first sub-band; and

modifying, by the audio signal encoder, the original envelope value of each of the M sub-bands using the modification factor, to obtain the modified envelope values of the M sub-bands.

7. The method according to claim 6, wherein the modification factor is greater than 1.

8. The method according to claim 6, wherein the modification factor is determined according to:

9. The method according to claim 1, wherein an energy of a sub-band of the N sub-bands is determined based on a quantized envelope value of the sub-band.

10. The method according to claim 9, wherein the energy of the sub-band is determined according to:

11. An audio signal processing device, 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;

obtain spectral coefficients of a current frame of an audio signal, wherein each of N sub-bands of the current frame comprises at least one spectral coefficient, and N is a positive integer greater than 1;

obtain a total energy of M sub-bands of the N sub-bands, a total energy of K sub-bands of the N sub-bands, and an energy of a first sub-band, wherein the M sub-bands and the K sub-bands have no overlap, M and K are positive integers, and N=M+K, wherein the energy of the first sub-band is the largest among energies of the M sub-bands;

determine whether to modify original envelope values of the M sub-bands based on a ratio of the total energy of the M sub-bands to the total energy of the K sub-bands and a ratio of energy of the first sub-band to the total energy of the M sub-bands;

based on a determination that the original envelope values of the M sub-bands need to be modified, modify the original envelope values of the M sub-bands individually to obtain modified envelope values of the M sub-bands, wherein the modified envelope values of the M sub-bands is one of determining factors for allocating encoding bits to the N sub-bands, wherein each of the N sub-bands has either at least one encoding bit allocated or no encoding bit allocated;

quantize spectral coefficients of each sub-band that has at least one encoding bits allocated; and

write the quantized spectral coefficients into a bitstream.

12. The device according to claim 11, wherein when the ratio of the total energy of the M sub-bands to the total energy of the K sub-bands falls in a first range, and the ratio of the energy of the first sub-band to the total energy of the M sub-bands is no less than a threshold, it is determined to modify the original envelope values of the M sub-bands.

13. The device according to claim 12, wherein the first range is [⅙

, ⅔

].

14. The device according to claim 12, wherein when an encoded bandwidth of the audio signal is 0 to 4 KHz, the threshold is

15. The device according to claim 12, wherein when an encoded bandwidth of the audio signal is 0 to 8 KHz, the threshold is

16. The device according to claim 11, wherein in modifying the original envelope values of the M sub-bands individually to obtain modified envelope values of the M sub-bands, the processor is configured to execute the processor-executable instructions to:

determine a modification factor for each of the M sub-bands according to the total energy of the M sub-bands and the energy of the first sub-band; and

modify the original envelope value of each of the M sub-bands using the modification factor, to obtain the modified envelope values of the M sub-bands.

17. The device according to claim 16, wherein the modification factor is greater than 1.

18. The device according to claim 16, wherein the modification factor is determined according to:

19. The device according to claim 11, wherein an energy of a sub-band of the N sub-bands is determined based on a quantized envelope value of the sub-band.

20. The device according to claim 19, wherein the energy of the sub-band is determined according to: