Audio signal coding method and apparatus

• US 9,514,762 B2
• Filed: 02/01/2016
• Issued: 12/06/2016
• Est. Priority Date: 10/08/2011
• 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: Miao, Lei, Liu, Zexin
• Primary Examiner(s): Pullias, Jesse
• Application Number:
  US15/011,824
• Publication Number:
  US 20160148622A1
• Time in Patent Office: 309 Days
• Field of Search: 704200-232, 704500-504
• US Class Current: 1/1
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/087 using mixed excitation models, e.g. MELP, MBE, split band LPC or HVXC
• CPC Class Codes: G10L 19/18 Vocoders using multiple modes
• CPC Class Codes: G10L 19/265 Pre-filtering, e.g. high frequency emphasis prior to encoding
• CPC Class Codes: G10L 21/038 using band spreading techniques
• CPC Class Codes: G10L 25/18 the extracted parameters being spectral information of each sub-band

Abstract

The present invention relates to an audio signal coding method and apparatus. The method includes: categorizing audio signals into high-frequency audio signals and low-frequency audio signals; coding the low-frequency audio signals by using a corresponding low-frequency coding manner according to characteristics of low-frequency audio signals; and selecting a bandwidth extension mode to code the high-frequency audio signals according to the low-frequency coding manner and/or characteristics of the audio signals.

Claims

1. An audio signal coding method, comprising:

categorizing, by a categorizing unit of an encoder, audio signals into high-frequency audio signals and low-frequency audio signals;

coding, by a low-frequency signal coding unit of an encoder, the low-frequency audio signals by using a time domain coding manner or a frequency domain coding manner; and

selecting, by a high-frequency signal coding unit of an encoder, a bandwidth extension mode to code the high-frequency audio signals according to a low-frequency coding manner or characteristics of the audio signals; and

wherein selecting the bandwidth extension mode to code the high-frequency audio signals according to the low-frequency coding manner comprises if the low-frequency audio signals should be coded by using the time domain coding manner, selecting a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals.

2. The audio signal coding method according to claim 1, wherein the selecting the bandwidth extension mode to code the high-frequency audio signals according to the low-frequency coding manner comprises determining that the frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

3. The audio signal coding method according to claim 1, wherein the selecting the bandwidth extension mode to code the high-frequency audio signals according to the characteristics of the audio signals specifically is:

if the audio signals are voice signals, selecting a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals;

if the audio signals are music signals, selecting a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

4. The audio signal coding apparatus according to claim 1, further comprising:

performing delay processing on the high-frequency audio signals or the low-frequency audio signals, so that delay of the high-frequency audio signals and delay of the low-frequency audio signals are the same at a decoding end.

5. The audio signal coding method according to claim 1, wherein the coding the high-frequency audio signals specifically comprises:

coding the high-frequency audio signals after performing first delay for the high-frequency audio signals, so that coding delay and decoding delay of the audio signals are a sum of the first delay and second delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

6. The audio signal coding method according to claim 1, wherein when first delay is smaller or equal to than second delay, the low-frequency audio signals are delayed by a difference between the second delay and the first delay after being coded, so that coding delay and decoding delay of the audio signals are the second delay;

when first delay is larger than second delay, the high-frequency audio signals are delayed by a difference between the first delay and the second delay after being coded, so that coding delay and decoding delay of the audio signals are the first delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

7. The audio signal coding method according to claim 1, wherein the coding the high-frequency audio signals specifically is:

coding the high-frequency audio signals after performing third delay for the high-frequency audio signals;

when first delay is smaller than or equal to second delay, the low-frequency audio signals are delayed by a difference between a sum of the second delay and the third delay, and the first delay after being coded, so that coding delay and decoding delay of the audio signals are the sum of the second delay and the third delay;

when first delay is larger than second delay, the high-frequency audio signals are delayed by a difference between the first delay and a sum of the second delay and the third delay after being coded, or the low-frequency audio signals are delayed by a difference between a sum of the second delay and the third delay, and the first delay, so that coding delay and decoding delay of the audio signals are the first delay or the sum of the second delay and the third delay.

8. An audio signal coding apparatus, comprising:

a categorizing unit, configured on a processor to categorize audio signals into high-frequency audio signals and low-frequency audio signals;

a low-frequency signal coding unit, configured on a processor to code the low-frequency audio signals by using a time domain coding manner or a frequency domain coding manner; and

a high-frequency signal coding unit, configured on a processor to select a bandwidth extension mode to code the high-frequency audio signals according to a low-frequency coding manner and/or characteristics of the audio signals; and

wherein the high-frequency signal coding unit is specifically configured to select a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals if the low-frequency audio signals should be coded by using the time domain coding manner;

select a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals if the low-frequency audio signals should be coded by using the frequency domain coding manner.

9. The audio signal coding apparatus according to claim 8, wherein if the audio signals are voice signals, the high-frequency signal coding unit is specifically configured to select a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals;

if the audio signals are music signals, the high-frequency signal coding unit is specifically configured to select a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

10. The audio signal coding apparatus according to claim 8, further comprising:

a low-frequency signal decoding unit, configured to decode the low-frequency audio signals;

wherein first delay is generated during the coding and decoding of the low-frequency audio signals;

wherein the high-frequency signal coding unit is specifically configured to after delaying the high-frequency audio signals by the first delay, code the delayed high-frequency audio signals, so that coding delay and decoding delay of the audio signals are a sum of the first delay and second delay, wherein the second delay is generated during the coding of the high-frequency audio signals.

11. The audio signal coding apparatus according to claim 8, wherein:

when first delay is smaller than or equal to second delay, the low-frequency signal coding unit is configured to after coding the low-frequency audio signals, delay the coded low-frequency audio signals by a difference between the second delay and the first delay, so that coding delay and decoding delay of the audio signals are the second delay;

when first delay is larger than second delay, the high-frequency signal coding unit is configured to after coding the high-frequency audio signals, delay the coded high-frequency signals by a difference between the first delay and the second delay, so that coding delay and decoding delay of the audio signals are the first delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

12. The audio signal coding apparatus according to claim 8, wherein:

the high-frequency signal coding unit is specifically configured to code the high-frequency audio signals after performing third delay for the high-frequency audio signals; and

when first delay is smaller than or equal to second delay, the low-frequency signal coding unit is configured to after coding the low-frequency audio signals, delay the coded low-frequency audio signals by a difference between a sum of the second delay and the third delay, and the first delay, so that coding delay and decoding delay of the audio signals are the sum of the second delay and the third delay;

when first delay is larger than second delay, the high-frequency signal coding unit is configured to after coding the high-frequency audio signals, delay the coded high-frequency audio signals by a difference between the first delay and a sum of the second delay and the third delay, or the low-frequency signal coding unit after coding the low-frequency audio signals, delays the coded low-frequency audio signals by a difference between a sum of the second delay and the third delay, and the first delay after coding the low-frequency audio signals, so that coding delay and decoding delay of the audio signals are the first delay or the sum of the second delay and the third delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

13. An audio signal coding method, comprising:

categorizing, by a categorizing unit on an encoder, audio signals into high-frequency audio signals and low-frequency audio signals;

coding, by a low-frequency signal coding unit on an encoder, the low-frequency audio signals by using a time domain coding manner or a frequency domain coding manner; and

selecting, by a high-frequency signal coding unit on an encoder, a bandwidth extension mode to code the high-frequency audio signals according to a low-frequency coding manner or characteristics of the audio signals; and

wherein the selecting the bandwidth extension mode to code the high-frequency audio signals according to the low-frequency coding manner and the characteristics of the audio signals specifically is;

if the low-frequency audio signals should be coded by using the time domain coding manner and the audio signals are voice signals, selecting a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals;

otherwise, selecting a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

14. The audio signal coding method according to claim 13, wherein the selecting the bandwidth extension mode to code the high-frequency audio signals according to the low-frequency coding manner comprises determining that the frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

15. The audio signal coding method according to claim 13, wherein the selecting the bandwidth extension mode to code the high-frequency audio signals according to the characteristics of the audio signals specifically is:

if the audio signals are voice signals, selecting a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals;

if the audio signals are music signals, selecting a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

16. The audio signal coding apparatus according to claim 13, further comprising:

performing delay processing on the high-frequency audio signals or the low-frequency audio signals, so that delay of the high-frequency audio signals and delay of the low-frequency audio signals are the same at a decoding end.

17. The audio signal coding method according to claim 13, wherein the coding the high-frequency audio signals specifically comprises:

coding the high-frequency audio signals after performing first delay for the high-frequency audio signals, so that coding delay and decoding delay of the audio signals are a sum of the first delay and second delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

18. The audio signal coding method according to claim 13, wherein when first delay is smaller or equal to than second delay, the low-frequency audio signals are delayed by a difference between the second delay and the first delay after being coded, so that coding delay and decoding delay of the audio signals are the second delay;

when first delay is larger than second delay, the high-frequency audio signals are delayed by a difference between the first delay and the second delay after being coded, so that coding delay and decoding delay of the audio signals are the first delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

19. The audio signal coding method according to claim 13, wherein the coding the high-frequency audio signals specifically is:

coding the high-frequency audio signals after performing third delay for the high-frequency audio signals;

when first delay is smaller than or equal to second delay, the low-frequency audio signals are delayed by a difference between a sum of the second delay and the third delay, and the first delay after being coded, so that coding delay and decoding delay of the audio signals are the sum of the second delay and the third delay;

when first delay is larger than second delay, the high-frequency audio signals are delayed by a difference between the first delay and a sum of the second delay and the third delay after being coded, or the low-frequency audio signals are delayed by a difference between a sum of the second delay and the third delay, and the first delay, so that coding delay and decoding delay of the audio signals are the first delay or the sum of the second delay and the third delay.

20. An audio signal coding apparatus, comprising:

a categorizing unit, configured on a processor to categorize audio signals into high-frequency audio signals and low-frequency audio signals;

a low-frequency signal coding unit, configured on a processor to code the low-frequency audio signals by using a time domain coding manner or a frequency domain coding manner; and

a high-frequency signal coding unit, configured on a processor to select a bandwidth extension mode to code the high-frequency audio signals according to a low-frequency coding manner and/or characteristics of the audio signals; and

wherein the high-frequency signal coding unit is specifically configured to select a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals if the low-frequency audio signals should be coded by using the time domain coding manner and the audio signals are voice signals;

otherwise, select a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

21. The audio signal coding apparatus according to claim 20, wherein if the audio signals are voice signals, the high-frequency signal coding unit is specifically configured to select a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals;

if the audio signals are music signals, the high-frequency signal coding unit is specifically configured to select a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

22. The audio signal coding apparatus according to claim 20, further comprising:

a low-frequency signal decoding unit, configured to decode the low-frequency audio signals;

wherein first delay is generated during the coding and decoding of the low-frequency audio signals;

wherein the high-frequency signal coding unit is specifically configured to after delaying the high-frequency audio signals by the first delay, code the delayed high-frequency audio signals, so that coding delay and decoding delay of the audio signals are a sum of the first delay and second delay, wherein the second delay is generated during the coding of the high-frequency audio signals.

23. The audio signal coding apparatus according to claim 20, wherein:

the high-frequency signal coding unit is specifically configured to code the high-frequency audio signals after performing third delay for the high-frequency audio signals; and

when first delay is smaller than or equal to second delay, the low-frequency signal coding unit is configured to after coding the low-frequency audio signals, delay the coded low-frequency audio signals by a difference between a sum of the second delay and the third delay, and the first delay, so that coding delay and decoding delay of the audio signals are the sum of the second delay and the third delay;

when first delay is larger than second delay, the high-frequency signal coding unit is configured to after coding the high-frequency audio signals, delay the coded high-frequency audio signals by a difference between the first delay and a sum of the second delay and the third delay, or the low-frequency signal coding unit after coding the low-frequency audio signals, delays the coded low-frequency audio signals by a difference between a sum of the second delay and the third delay, and the first delay after coding the low-frequency audio signals, so that coding delay and decoding delay of the audio signals are the first delay or the sum of the second delay and the third delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

24. An audio signal coding apparatus, comprising:

a categorizing unit, configured on a processor to categorize audio signals into high-frequency audio signals and low-frequency audio signals;

a low-frequency signal coding unit, configured on a processor to code the low-frequency audio signals by using a time domain coding manner or a frequency domain coding manner; and

a high-frequency signal coding unit, configured on a processor to select a bandwidth extension mode to code the high-frequency audio signals according to a low-frequency coding manner and/or characteristics of the audio signals; and

wherein;

when first delay is smaller than or equal to second delay, the low-frequency signal coding unit is configured to after coding the low-frequency audio signals, delay the coded low-frequency audio signals by a difference between the second delay and the first delay, so that coding delay and decoding delay of the audio signals are the second delay;

when first delay is larger than second delay, the high-frequency signal coding unit is configured to after coding the high-frequency audio signals, delay the coded high-frequency signals by a difference between the first delay and the second delay, so that coding delay and decoding delay of the audio signals are the first delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.

25. The audio signal coding apparatus according to claim 24, wherein the high-frequency signal coding unit is specifically configured to select a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals if the low-frequency audio signals should be coded by using the time domain coding manner;

select a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals if the low-frequency audio signals should be coded by using the frequency domain coding manner.

26. The audio signal coding apparatus according to claim 24, wherein if the audio signals are voice signals, the high-frequency signal coding unit is specifically configured to select a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals;

if the audio signals are music signals, the high-frequency signal coding unit is specifically configured to select a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

27. The audio signal coding apparatus according to claim 24, wherein the high-frequency signal coding unit is specifically configured to select a time domain bandwidth extension mode to perform time domain coding for the high-frequency audio signals if the low-frequency audio signals should be coded by using the time domain coding manner and the audio signals are voice signals;

otherwise, select a frequency domain bandwidth extension mode to perform frequency domain coding for the high-frequency audio signals.

28. The audio signal coding apparatus according to claim 24, further comprising:

a low-frequency signal decoding unit, configured to decode the low-frequency audio signals;

wherein first delay is generated during the coding and decoding of the low-frequency audio signals;

wherein the high-frequency signal coding unit is specifically configured to after delaying the high-frequency audio signals by the first delay, code the delayed high-frequency audio signals, so that coding delay and decoding delay of the audio signals are a sum of the first delay and second delay, wherein the second delay is generated during the coding of the high-frequency audio signals.

29. The audio signal coding apparatus according to claim 24, wherein:

the high-frequency signal coding unit is specifically configured to code the high-frequency audio signals after performing third delay for the high-frequency audio signals; and

when first delay is smaller than or equal to second delay, the low-frequency signal coding unit is configured to after coding the low-frequency audio signals, delay the coded low-frequency audio signals by a difference between a sum of the second delay and the third delay, and the first delay, so that coding delay and decoding delay of the audio signals are the sum of the second delay and the third delay;

when first delay is larger than second delay, the high-frequency signal coding unit is configured to after coding the high-frequency audio signals, delay the coded high-frequency audio signals by a difference between the first delay and a sum of the second delay and the third delay, or the low-frequency signal coding unit after coding the low-frequency audio signals, delays the coded low-frequency audio signals by a difference between a sum of the second delay and the third delay, and the first delay after coding the low-frequency audio signals, so that coding delay and decoding delay of the audio signals are the first delay or the sum of the second delay and the third delay;

wherein the first delay is delay generated during coding and decoding of the low-frequency audio signals, and the second delay is delay generated during coding of the high-frequency audio signals.