Systems and methods of performing noise modulation and gain adjustment

• US 9,601,125 B2
• Filed: 08/28/2013
• Issued: 03/21/2017
• Est. Priority Date: 02/08/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Atti, Venkatraman Srinivasa, Krishnan, Venkatesh
• Primary Examiner(s): MCFADDEN, SUSAN IRIS
• Application Number:
  US14/012,749
• Publication Number:
  US 20140229172A1
• Time in Patent Office: 1,301 Days
• Field of Search: 704/225
• US Class Current: 1/1
• CPC Class Codes: G10L 19/032 Quantisation or dequantisation of spectral components
• CPC Class Codes: G10L 19/035 Scalar quantisation
• CPC Class Codes: G10L 19/06 Determination or coding of the spectral characteristics, e.g. of the short-term prediction coefficients
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: G10L 2019/0003 Backward prediction of gain
• CPC Class Codes: G10L 21/038 using band spreading techniques
• CPC Class Codes: H03G 3/301 the gain being continuously variable
• CPC Class Codes: H03G 3/3089 Control of digital or coded signals

Abstract

A method includes receiving a first value of a mixing factor. The first value corresponds to a first portion of an audio signal received at an audio encoder. The method includes receiving a second value of the mixing factor. The second value corresponds to a second portion of the audio signal. The method also includes generating a third value of the mixing factor at least partially based on the first value and the second value and mixing an excitation signal with modulated noise based on the third value. Another method includes determining a first set of spectral frequency values corresponding to an audio signal and determining a second set of spectral frequency values that approximates the first set of spectral frequency values. A gain value corresponding to at least a portion of the audio signal is adjusted based on a difference between the first set and the second set.

Claims

1. A method of synthesizing a high-band signal in an electronic device, the method comprising:

receiving a first value of a mixing factor, the first value corresponding to a first portion of an audio signal received at an audio coder of the electronic device;

receiving a second value of the mixing factor, the second value corresponding to a second portion of the audio signal;

generating a third value of the mixing factor at least partially based on the first value, the second value, and an indication of a coding type corresponding to the audio signal; and

generating a high-band excitation signal based on an excitation signal, modulated noise, and the third value of the mixing factor, wherein a gain value corresponding to at least a portion of the audio signal is used to generate a synthesized high-band signal based on the high-band excitation signal.

2. The method of claim 1, wherein the high-band excitation signal corresponds to a high-band portion of the audio signal, wherein the high-band excitation signal is generated based on combining, based on the third value of the mixing factor, the modulated noise and the excitation signal, wherein the excitation signal corresponds to a transformed version of a low-band excitation signal, the low-band excitation signal corresponding to a low-band portion of the audio signal, and wherein the electronic device comprises a mobile device.

3. The method of claim 2, wherein the high-band excitation signal comprises a weighted sum of the modulated noise and the transformed version of the low-band excitation signal.

4. The method of claim 1, wherein the first value is generated based on a low-band portion of a first sub-frame of the audio signal and wherein the second value is generated based on a low-band portion of a second sub-frame of the audio signal.

5. The method of claim 1, wherein generating the third value comprises determining a weighted sum of the first value and the second value.

6. The method of claim 5, wherein a first weight applied to the first value and a second weight applied to the second value are determined based on high-band energy fluctuation of the audio signal.

7. The method of claim 6, wherein the first weight and the second weight are determined based on a first high-band energy value corresponding to the first portion and further based on a second high-band energy value corresponding to the second portion.

8. The method of claim 7, wherein the first weight is selected to be greater than the second weight in response to the first high-band energy value exceeding a first threshold or in response to the second high-band energy value exceeding a second threshold, wherein the first threshold corresponds to the second high-band energy value scaled by a scaling factor, and wherein the second threshold corresponds to the first high-band energy value scaled by the scaling factor.

9. The method of claim 1, wherein generating the third value is further based on a spectral distortion corresponding to the audio signal.

10. The method of claim 1, wherein receiving the first value, receiving the second value, generating the third value, and generating the high-band excitation signal are performed by a media capture device.

11. The method of claim 1, wherein the first portion comprises a first sub-frame of the audio signal, wherein the second portion comprises a second sub-frame of the audio signal.

12. The method of claim 1, further comprising outputting high-band side information based on mixing the excitation signal with the modulated noise and adjusting the gain value.

13. The method of claim 12, wherein the gain value is adjusted based on a first set of spectral frequency values corresponding to the audio signal and a second set of spectral frequency values that approximates the first set of spectral frequency values.

14. The method of claim 1, wherein the audio coder comprises an encoder.

15. The method of claim 1, wherein the audio coder comprises a decoder.

16. The method of claim 1, further comprising receiving, via a microphone, the audio signal.

17. The method of claim 1, wherein the high-band excitation signal corresponds to a high-band portion of the audio signal, and wherein the high-band excitation signal is generated based on applying the third value of the mixing factor to the modulated noise and to the excitation signal to calculate a weighted sum of a first product of the third value and the modulated noise and a second product of the third value and the excitation signal.

18. The method of claim 17, wherein the gain value is determined based on a comparison of the synthesized high-band signal to a high-band signal of the audio signal.

19. The method of claim 1, further comprising determining the gain value based on the high-band excitation signal.

20. The method of claim 1, wherein the electronic device includes a communication device, and wherein receiving the first value, receiving the second value, generating the third value, and mixing the excitation signal with the modulated noise are performed by the communication device.

21. The method of claim 1, wherein the electronic device comprises a mobile communication device that receives a signal corresponding to the audio signal via at least one of a microphone or an antenna.

22. The method of claim 1, wherein receiving the first value, receiving the second value, generating the third value, and generating the high-band excitation signal are performed by a media playback device.

23. An apparatus for synthesizing a high-band signal in an electronic device, the apparatus comprising:

a filter configured to generate a third value of a mixing factor at least partially based on a first value of the mixing factor, a second value of the mixing factor, and an indication of a coding type corresponding to an audio signal received at the electronic device, wherein the first value corresponds to a first portion of the audio signal and wherein the second value corresponds to a second portion of the audio signal;

a mixer configured to receive the third value and to generate a high-band excitation signal corresponding to a high-band portion of the audio signal by generating modulated noise and combining the modulated noise and a transformed version of a low-band excitation signal, the low-band excitation signal corresponding to a low-band portion of the audio signal, wherein the mixer is configured to combine the modulated noise and the transformed version of the low-band excitation signal based on the third value; and

a gain circuit configured to determine a gain value corresponding to at least a portion of the audio signal, the gain value usable to generate a synthesized high-band signal based on the high-band excitation signal.

24. The apparatus of claim 23, wherein generating the third value is further based on a spectral distortion corresponding to the audio signal.

25. The apparatus of claim 23, further comprising:

an analysis filter configured to determine a first set of spectral frequency values corresponding to the audio signal; and

a quantizer configured to generate a second set of spectral frequency values that approximates the first set of spectral frequency values, wherein the gain circuit is further configured to adjust the gain value based on a difference between the first set and the second set, and wherein the gain value corresponds to at least one of the first portion or the second portion of the audio signal.

26. The apparatus of claim 23, wherein the filter is configured to determine a weighted sum of the first value and the second value.

27. The apparatus of claim 26, wherein a first weight applied to the first value and a second weight applied to the second value are determined based on high-band energy fluctuation of the audio signal.

28. The apparatus of claim 27, wherein the first weight and the second weight are determined based on a first high-band energy value corresponding to the first portion and further based on a second high-band energy value corresponding to the second portion.

29. The apparatus of claim 28, wherein the first weight is selected to be greater than the second weight in response to the first high-band energy value exceeding a first threshold or in response to the second high-band energy value exceeding a second threshold, wherein the first threshold corresponds to the second high-band energy value scaled by a scaling factor, and wherein the second threshold corresponds to the first high-band energy value scaled by the scaling factor.

30. The apparatus of claim 23, wherein the filter and the mixer are included in an encoder.

31. The apparatus of claim 23, wherein the filter and the mixer are included in a decoder.

32. The apparatus of claim 23, further comprising an input device configured to receive the audio signal.

33. The apparatus of claim 23, wherein the at least a portion of the audio signal includes a frame of the audio signal.

34. The apparatus of claim 23, further comprising:

an antenna; and

a receiver coupled to the antenna and configured to receive the audio signal.

35. The apparatus of claim 34, further comprising:

a processor coupled to the receiver; and

a coder coupled to the processor.

36. The apparatus of claim 35, wherein the electronic device includes a communication device, and wherein the receiver, the processor, and the coder are integrated into the communication device.

37. The apparatus of claim 35, wherein the receiver, the processor, and the coder are integrated into a communication device.

38. The apparatus of claim 35, wherein the receiver, the processor, and the coder are integrated into a media playback device.

39. The apparatus of claim 35, wherein the receiver, the processor, and the coder are integrated into a media capture device.

40. An apparatus for synthesizing a high-band signal in an electronic device, the apparatus comprising:

means for generating a third value of a mixing factor at least partially based on a first value of the mixing factor, a second value of the mixing factor, and an indication of a coding type corresponding to an audio signal, wherein the first value corresponds to a first portion of the audio signal received at an audio coder of the electronic device and wherein the second value corresponds to a second portion of the audio signal;

means for generating a high-band excitation signal corresponding to a high-band portion of the audio signal by combining modulated noise and a transformed version of a low-band excitation signal, the low-band excitation signal corresponding to a low-band portion of the audio signal, wherein the means for generating is configured to combine the modulated noise and the transformed version of the low-band excitation signal based on the third value; and

means for determining a gain value corresponding to at least a portion of the audio signal, the gain value usable to generate a synthesized high-band signal based on the high-band excitation signal.

41. The apparatus of claim 40, wherein a first weight applied to the first value and a second weight applied to the second value are determined based on high-band energy fluctuation of the audio signal.

42. The apparatus of claim 40, wherein the third value is generated further based on a spectral distortion corresponding to the audio signal.

43. The apparatus of claim 40, wherein the electronic device includes a communication device, and wherein the means for generating the third value and the means for generating the high-band excitation signal are integrated into the communication device.

44. The apparatus of claim 40, wherein the electronic device comprises a mobile communication device including at least one of a microphone or an antenna configured to receive a signal corresponding to the audio signal.

45. The apparatus of claim 40, wherein the means for generating the third value and the means for generating the high-band excitation signal are integrated into a media playback device, a media capture device, or a combination thereof.

46. A non-transitory computer-readable medium comprising instructions that, when executed by a computer in an electronic device configured to synthesize a high-band signal, cause the computer to:

receive a first value of a mixing factor, the first value corresponding to a first portion of an audio signal received at an audio coder of the electronic device;

receive a second value of the mixing factor, the second value corresponding to a second portion of the audio signal;

generate a third value of the mixing factor at least partially based on the first value, the second value, and an indication of a coding type corresponding to the audio signal; and

generate a high-band excitation signal based on an excitation signal, modulated noise, and the third value of the mixing factor, wherein a gain value corresponding to at least a portion of the audio signal is usable to generate a synthesized high-band signal based on the high-band excitation signal.

47. The non-transitory computer-readable medium of claim 46, further comprising instructions that, when executed by the computer, cause the computer to generate the high-band excitation signal corresponding to a high-band portion of the audio signal, wherein the excitation signal corresponds to a transformed version of a low-band excitation signal, the low-band excitation signal corresponding to a low-band portion of the audio signal.

48. The non-transitory computer-readable medium of claim 47, wherein the high-band excitation signal comprises a weighted sum of the modulated noise and the transformed version of the low-band excitation signal.

49. The non-transitory computer-readable medium of claim 46, wherein the first value is generated based on a low-band portion of a first sub-frame of the audio signal and wherein the second value is generated based on a low-band portion of a second sub-frame of the audio signal.