Audio coding method and related apparatus

• US 10,504,534 B2
• Filed: 01/31/2019
• Issued: 12/10/2019
• Est. Priority Date: 07/28/2014
• 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: Liu, Zexin, Miao, Lei
• Primary Examiner(s): Saint Cyr, Leonard
• Application Number:
  US16/263,837
• Publication Number:
  US 20190164562A1
• Time in Patent Office: 313 Days
• Field of Search: 704500-504
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/0208 Subband vocoders
• CPC Class Codes: G10L 19/0212 using orthogonal transformation
• CPC Class Codes: G10L 19/12 the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders
• CPC Class Codes: G10L 19/22 Mode decision, i.e. based on audio signal content versus external parameters
• CPC Class Codes: G10L 25/18 the extracted parameters being spectral information of each sub-band
• CPC Class Codes: G10L 25/21 the extracted parameters being power information

Abstract

An audio encoding method and a related apparatus, where the audio coding method includes obtaining an audio signal, obtaining some subband parameters of a current frame of the audio signal, and encoding the current frame using a high quality transform coding (HQ) algorithm based on the obtained subband parameters. The audio encoding method and the related apparatus help improve encoding quality or encoding efficiency in audio signal encoding.

Claims

1. An audio signal encoding method, comprising:

obtaining, by an audio signal encoder, an audio signal, wherein the audio signal comprises a current frame, and wherein the current frame comprises a subband i, a subband j, a subband x, and a subband y;

obtaining, by the audio signal encoder, an average energy of the subband i, an average energy of the subband j, a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y; and

encoding, by the audio signal encoder, the current frame using a high quality transform coding (HQ) algorithm when the average energy of the subband j is greater than a product of the average energy of the subband i multiplied by a first constant (T4), a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a lowest value of a first interval (R1), and the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a highest value of the R1.

2. The audio signal encoding method of claim 1, wherein a highest frequency bin of the subband i is lower than a lowest frequency bin of the subband j, wherein a highest frequency bin of the subband j is higher than eight kilohertz (kHz), and wherein a highest frequency bin of the subband x is lower than a lowest frequency bin of the subband y.

3. The audio signal encoding method of claim 1, wherein the constant T4 is less than one divided by one point two and greater than or equal to zero point five.

4. The audio signal encoding method of claim 1, wherein a lowest frequency bin of a range of frequency bins of the subband i is zero point four kilohertz (kHz), wherein a range of frequency bins of the subband j is four point eight kHz to nine point six kHz, wherein a range of frequency bins of the subband x is one kHz to two point six kHz, and wherein a range of frequency bins of the subband y is four point eight kHz to six point four kHz.

5. An audio signal encoding method, comprising:

obtaining, by an audio signal encoder, an audio signal, wherein the audio signal comprises a current frame, and wherein the current frame comprises a subband x and a subband y;

obtaining, by the audio signal encoder, a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y;

encoding, by the audio signal encoder, the current frame using a high quality transform coding (HQ) algorithm when a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a first constant (T44), and the spectral peak of the subband y is greater than a product of the spectral average of the subband y multiplied by a second constant (T45); and

encoding, by the audio signal encoder, the current frame using the HQ algorithm when the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a third constant (T46), and the spectral peak of the subband y is less than a product of the spectral average of the subband y multiplied by the T45.

6. The audio signal encoding method of claim 5, wherein the T47 is one point five, and wherein the T45 is one point five.

7. The audio signal encoding method of claim 5, wherein a range of frequency bins of the subband x is one kilohertz (kHz) to two point six kHz, and wherein a range of frequency bins of the subband y is four point eight kHz to six point four kHz.

8. An audio signal encoder, comprising:

a memory storing program instructions; and

at least one processor coupled to the memory, wherein the program instructions cause the at least one processor to be configured to;

obtain an audio signal, wherein the audio signal comprises a current frame, and wherein the current frame comprises a subband i, a subband j, a subband x, and a subband y;

obtain an average energy of the subband i, an average energy of the subband j, a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y; and

encode the current frame using a high quality transform coding (HQ) algorithm when the average energy of the subband j is greater than a product of the average energy of the subband i multiplied by a first constant (T4), a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a lowest value of a first interval (R1), and the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a highest value of the R1.

9. The audio signal encoder of claim 8, wherein a highest frequency bin of the subband i is lower than a lowest frequency bin of the subband j, wherein a highest frequency bin of the subband j is higher than eight kilohertz (kHz), and wherein a highest frequency bin of the subband x is lower than a lowest frequency bin of the subband y.

10. The audio signal encoder of claim 8, wherein the T4 is less than one divided by one point two and greater than or equal to zero point five.

11. The audio signal encoder of claim 8, wherein a lowest frequency bin of a range of frequency bins of the subband i is zero point four kilohertz (kHz), wherein a range of frequency bins of the subband j is four point eight kHz to nine point six kHz, wherein a range of frequency bins of the subband x is one kHz to two point six kHz, and wherein a range of frequency bins of the subband y is four point eight kHz to six point four kHz.

12. An audio signal encoder, comprising:

a memory storing program instructions; and

at least one processor coupled to the memory, wherein the program instructions cause the at least one processor to be configured to;

obtain an audio signal, wherein the audio signal comprises a current frame, and wherein the current frame comprises a subband x and a subband y;

obtain a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y;

encode the current frame using a high quality transform coding (HQ) algorithm when a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a first constant (T44), and the spectral peak of the subband y is greater than a product of the spectral average of the subband y multiplied by a second constant (T45); and

encode the current frame using the HQ algorithm when the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a third constant (T46), and the spectral peak of the subband y is less than a product of the spectral average of the subband y multiplied by the T47.

13. The audio signal encoder of claim 12, wherein the T47 is one point five, and wherein the T45 is one point five.

14. The audio signal encoder of claim 12, wherein a range of frequency bins of the subband x is one kilohertz (kHz) to two point six kHz, and wherein a range of frequency bins of the subband y is four point eight kHz to six point four kHz.

15. An audio signal encoder, comprising:

a hardware circuit configured to obtain an audio signal, wherein the audio signal comprises a current frame, and wherein the current frame comprises a subband i, a subband j, a subband x, and a subband y;

a hardware circuit configured to obtain an average energy of the subband i, an average energy of the subband j, a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y; and

a hardware circuit configured to encode the current frame using a high quality transform coding (HQ) algorithm when the average energy of the subband j is greater than a product of the average energy of the subband i multiplied by a first constant (T4), a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a lowest value of a first interval (RI), and the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x and multiplied by a highest value of the RI.

16. The audio signal encoder of claim 15, wherein a highest frequency bin of the subband i is lower than a lowest frequency bin of the subband j, wherein a highest frequency bin of the subband j is higher than eight kilohertz (kHz), and wherein a highest frequency bin of the subband x is lower than a lowest frequency bin of the subband y.

17. The audio signal encoder of claim 15, wherein the T4 is less than one divided by one point two and greater than or equal to zero point five.

18. The audio signal encoder of claim 15, wherein a lowest frequency bin of a range of frequency bins of the subband i is zero point four kilohertz (kHz), wherein a range of frequency bins of the subband j is four point eight kHz to nine point six kHz, wherein a range of frequency bins of the subband x is one kHz to two point six kHz, and wherein a range of frequency bins of the subband y is four point eight kHz to six point four kHz.

19. An audio signal encoder, comprising:

a hardware circuit configured to obtain an audio signal, wherein the audio signal comprises a current frame, and wherein the current frame comprises a subband x and a subband y; and

a hardware circuit configured to obtain a spectral peak of the subband x, a spectral average of the subband x, a spectral peak of the subband y, and a spectral average of the subband y; and

a hardware circuit configured to;

encode the current frame using a high quality transform coding (HQ) algorithm when a product of the spectral peak of the subband x multiplied by the spectral average of the subband y is less than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a first constant (T44), and the spectral peak of the subband y is greater than a product of the spectral average of the subband y multiplied by a second constant (T45); and

encode the current frame using the HQ algorithm when the product of the spectral peak of the subband x multiplied by the spectral average of the subband y is greater than a product of the spectral peak of the subband y multiplied by the spectral average of the subband x multiplied by a third constant (T46), and the spectral peak of the subband y is less than a product of the spectral average of the subband y multiplied by the T47.

20. The audio signal encoder of claim 19, wherein the T47 is one point five, and wherein the T45 is one point five.

21. The audio signal encoder of claim 19, wherein a range of frequency bins of the subband x is one kilohertz (kHz) to two point six kHz, and wherein a range of frequency bins of the subband y is four point eight kHz to six point four kHz.