Signal processing method and device

• US 10,186,271 B2
• Filed: 08/25/2017
• Issued: 01/22/2019
• 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): Cyr, Leonard Saint
• Application Number:
  US15/686,175
• Publication Number:
  US 20170352358A1
• Time in Patent Office: 515 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 pertains to an audio signal processing method and device. A current frame of a frequency-domain audio signal has N frequency sub-bands. According to an energy attribute and a spectral attribute of a first subset of M sub-bands, whether to adjust envelope values of the M sub-bands is determined. Based on a determination that the energy envelope values of the M sub-bands need to be adjusted, the energy 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 adjusted envelope values of the M sub-bands and energy envelope information of K sub-bands of a second subset. The first subset and the second subset have no overlap in frequency, and N=M+K.

Claims

1. An audio signal encoding method, comprising:

obtaining, by an audio signal encoder, spectral coefficients of a current frame of an audio signal, wherein each of the spectral coefficients belong to one of N sub-bands of the current frame, and N is a positive integer;

obtaining, by the audio signal encoder, a total energy of M sub-bands in the N sub-bands, wherein M is a positive integer and M≤

N;

determining, by the audio signal encoder, whether a ratio of an energy of a first sub-band to the total energy of the M sub-bands falls within a first range, wherein the energy of the first sub-band is the largest among energies of the M sub-bands;

at least based on a determination that the ratio of the energy of the first sub-band to the total energy of the M sub-bands falls within the first range, determining, by the audio signal encoder, whether to adjust quantized envelope values of the M sub-bands;

based on a determination that the quantized envelope values of the M sub-bands need to be adjusted, adjusting, by the audio signal encoder, the quantized envelope values of the M sub-bands to obtain adjusted envelope values of the M sub-bands;

allocating, by the audio signal encoder, encoding bits for the N sub-bands of the current frame at least based on the adjusted envelope values of the M sub-bands, wherein each of the N sub-bands is either having encoding bits allocated or not having any encoding bits allocated;

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

writing, by the audio signal encoder, the quantized spectral coefficients of the sub-bands that have encoding bits allocated into a bitstream.

2. The method according to claim 1, further comprising:

obtaining a total energy of other N-M sub-bands, wherein the other N-M sub-bands and the M sub-bands have no overlap;

wherein whether to adjust quantized envelope values of the M sub-bands is further determined according to whether a ratio of the total energy of the M sub-bands to the total energy of the M sub-bands to the total energy of the other N-M sub-bands falls within a second range.

3. The method according to claim 2, wherein when the ratio of the total energy of the M sub-bands to the total energy of the other N-M sub-bands falls within the second range, and the ratio of the energy of the first sub-band to the total energy of the M sub-bands falls within the first range, it is determined to adjust the quantized envelope values of the M sub-bands.

4. The method according to claim 3, wherein the second range is [⅙

, ⅔

].

5. The method according to claim 3, wherein when an encoded bandwidth of the audio signal is 0 to 4 KHz, the first range is

6. The method according to claim 3, wherein when an encoded bandwidth of the audio signal is 0 to 8 KHz, the first range is

7. The method according to claim 1, wherein adjusting the quantized envelope values of the M sub-bands to obtain adjusted envelope values of the M sub-bands comprises:

determining, according to the total energy of the M sub-bands and the energy of the first sub-band, an adjustment factor for each of the M sub-bands; and

adjusting the quantized envelope value of each of the M sub-bands using the determined adjustment factor for each of the M sub-bands, to obtain the adjusted envelope values of the M sub-bands.

8. The method according to claim 7, wherein the adjustment factor is determined according to:

9. The method according to claim 1, wherein an adjusted envelope value of each of the M sub-bands is greater than a quantized envelope value of the same sub-band.

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

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

12. An audio signal encoding device comprising:

a memory for storing program instructions; and

a processor operatively coupled to the memory,

wherein, by executing the program instructions by the processor, the encoding device is configured to;

obtain spectral coefficients of a current frame of an audio signal, wherein each of the spectral coefficients belong to one of N frequency sub-bands of the current frame, and N is a positive integer;

obtain a total energy of M sub-bands in the N sub-bands, wherein M is a positive integer and M≤

N;

determine whether a ratio of an energy of a first sub-band to the total energy of the M sub-bands falls within a first range, wherein the energy of the first sub-band is the largest among energies of the M sub-bands;

at least based on a determination that the ratio of the energy of the first sub-band to the total energy of the M sub-bands falls within the first range, determine whether to adjust quantized envelope values of the M sub-bands;

based on a determination that the quantized envelope values of the M sub-bands need to be adjusted, adjust the quantized envelope values of the M sub-bands to obtain adjusted envelope values of the M sub-bands;

allocate encoding bits for the N sub-bands of the current frame at least based on the adjusted envelope values of the M sub-bands, wherein each of the N sub-bands is either having encoding bits allocated or not having any encoding bits allocated;

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

write the quantized spectral coefficients of the sub-bands that have encoding bits allocated into a bitstream.

13. The device according to claim 12, wherein the processor, by executing the program instructions, is further configured to:

obtain a total energy of other N-M sub-bands, wherein the other N-M sub-bands and the M sub-bands have no overlap;

wherein whether to adjust quantized envelope values of the M sub-bands is further determined according to whether a ratio of the total energy of the M sub-bands to the total energy of the other N-M sub-bands falls within a second range.

14. The device according to claim 13, wherein when the ratio of the total energy of the M sub-bands to the total energy of the other N-M sub-bands falls within the second range, and the ratio of the energy of the first sub-band to the total energy of the M sub-bands falls within the first range, it is determined to adjust the quantized envelope values of the M sub-bands.

15. The device according to claim 14, wherein the second range is [⅙

, ⅔

].

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

17. The device according to claim 14, wherein when an encoded bandwidth of the audio signal is 0 to 8 KHz, the first range is

18. The device according to claim 12, wherein in adjusting the quantized envelope values of the M sub-bands to obtain adjusted envelope values of the M sub-bands, the encoding device, by executing the program instructions by the processor, is configured to:

determine, according to the total energy of the M sub-bands and the energy of the first sub-band, an adjustment factor for each of the M sub-bands; and

adjust the quantized envelope value of each of the M sub-bands using the determined adjustment factor for each of the M sub-bands, to obtain the adjusted envelope values of the M sub-bands.

19. The device according to claim 18, wherein the adjustment factor is determined according to:

20. The device according to claim 12, wherein an adjusted envelope value of each of the M sub-bands is greater than a quantized envelope value of the same sub-band.

21. The device according to claim 12, wherein energy of a sub-band of the N sub-bands is determined based on a quantized envelope value of the sub-band.

22. The device according to claim 21, wherein the energy of the sub-band is determined according to: