Methods and apparatus for providing a distinct perceptual location for an audio source within an audio mixture

• US 8,660,280 B2
• Filed: 11/28/2007
• Issued: 02/25/2014
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Xiang, Pei, Gupta, Samir Kumar, Choy, Eddie L. T., Kulkarni, Prajakt V.
• Primary Examiner(s): Talpalatski, Alexander
• Application Number:
  US11/946,365
• Publication Number:
  US 20090136044A1
• Time in Patent Office: 2,281 Days
• Field of Search: 381/17, 381/18, 381300-311, 381/61, 381/63, 381/1
• US Class Current: 381/310
• CPC Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• CPC Class Codes: H04S 7/30 Control circuits for electronic adaptation of the sound field
• CPC Class Codes: H04S 7/302 Electronic adaptation of stereophonic sound system to listener position or orientation H04S7/301 takes precedence

Abstract

In accordance with a method for providing a distinct perceptual location for an audio source within an audio mixture, a foreground signal may be processed to provide a foreground perceptual angle for the foreground signal. The foreground signal may also be processed to provide a desired attenuation level for the foreground signal. A background signal may be processed to provide a background perceptual angle for the background signal. The background signal may also be processed to provide a desired attenuation level for the background signal. The foreground signal and the background signal may be combined into an output audio source.

Claims

1. A method for providing a distinct perceptual location for an audio source within an audio mixture, comprising:

processing a foreground signal to provide a foreground perceptual angle for the foreground signal;

processing the foreground signal to provide a desired attenuation level for the foreground signal;

processing a background signal that has been low-pass filtered to provide a background perceptual angle for the background signal;

processing the background signal to provide a desired attenuation level for the background signal, wherein the background signal is processed to sound more diffuse than the foreground signal, wherein attenuation is applied to a first background channel based on a sampling rate of a delay line applied to a second background channel; and

combining the foreground signal and the background signal into an output audio source.

2. The method of claim 1, wherein an input audio source is a stereo audio source, and further comprising:

processing the foreground signal to balance contents of left and right channels of the foreground signal; and

processing the background signal to balance contents of left and right channels of the background signal.

3. The method of claim 1, further comprising gradually changing the perceptual location of the output audio source from a current perceptual location to a new perceptual location.

4. The method of claim 1, further comprising changing the perceptual location of the output audio source from a current perceptual location in a background region to a new perceptual location in a foreground region by:

changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of the new perceptual location;

changing foreground attenuation scalars in order to decrease attenuation of the foreground signal; and

changing background attenuation scalars in order to increase attenuation of the background signal.

5. The method of claim 1, further comprising changing the perceptual location of the output audio source from a current perceptual location in a foreground region to a new perceptual location in a background region by:

changing background control scalars to correspond to a background angle of the new perceptual location;

changing background attenuation scalars in order to decrease attenuation of the background signal; and

changing foreground attenuation scalars in order to increase attenuation of the foreground signal.

6. The method of claim 1, further comprising changing the perceptual location of the output audio source within a foreground region by gradually changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of a new perceptual location.

7. The method of claim 1, further comprising changing the perceptual location of the output audio source within a background region by gradually changing background control scalars to correspond to a background angle of a new perceptual location.

8. An apparatus for providing a distinct perceptual location for an audio source within an audio mixture, comprising:

a foreground angle control component that is configured to process a foreground signal to provide a foreground perceptual angle for the foreground signal;

a foreground attenuation component that is configured to process the foreground signal to provide a desired attenuation level for the foreground signal;

a background angle control component that is configured to process a background signal that has been low-pass filtered to provide a background perceptual angle for the background signal;

a background attenuation component that is configured to process the background signal to provide a desired attenuation level for the background signal, wherein the background signal is processed to sound more diffuse than the foreground signal, wherein attenuation is applied to a first background channel based on a sampling rate of a delay line applied to a second background channel; and

an adder that is configured to combine the foreground signal and the background signal into an output audio source.

9. The apparatus of claim 8, wherein an input audio source is a stereo audio source, wherein the foreground angle control component is further configured to process the foreground signal to balance contents of left and right channels of the foreground signal, and wherein the background angle control component is further configured to process the background signal to balance contents of left and right channels of the background signal.

10. The apparatus of claim 8, wherein the foreground angle control component, the foreground attenuation component, and the background attenuation component are configured to change the perceptual location of the output audio source from a current perceptual location in a background region to a new perceptual location in a foreground region by:

changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of the new perceptual location;

changing foreground attenuation scalars in order to decrease attenuation of the foreground signal; and

changing background attenuation scalars in order to increase attenuation of the background signal.

11. The apparatus of claim 8, wherein the foreground attenuation component, the background angle control component, and the background attenuation component are configured to change the perceptual location of the output audio source from a current perceptual location in a foreground region to a new perceptual location in a background region by:

changing background control scalars to correspond to a background angle of the new perceptual location;

changing background attenuation scalars in order to decrease attenuation of the background signal; and

changing foreground attenuation scalars in order to increase attenuation of the foreground signal.

12. The apparatus of claim 8, wherein the foreground angle control component is configured to change the perceptual location of the output audio source within a foreground region by gradually changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of a new perceptual location.

13. The apparatus of claim 8, wherein the background angle control component is configured to change the perceptual location of the output audio source within a background region by gradually changing background control scalars to correspond to a background angle of a new perceptual location.

14. A non-transitory computer-readable medium comprising instructions providing a distinct perceptual location for an audio source within an audio mixture, which when executed by a processor causes the processor to:

process a foreground signal to provide a foreground perceptual angle for the foreground signal;

process the foreground signal to provide a desired attenuation level for the foreground signal;

process a background signal that has been low-pass filtered to provide a background perceptual angle for the background signal;

process the background signal to provide a desired attenuation level for the background signal, wherein the background signal is processed to sound more diffuse than the foreground signal, wherein attenuation is applied to a first background channel based on a sampling rate of a delay line applied to a second background channel; and

combine the foreground signal and the background signal into an output audio source.

15. The computer-readable medium of claim 14, wherein an input audio source is a stereo audio source, and wherein the instructions also cause the processor to:

process the foreground signal to balance contents of left and right channels of the foreground signal; and

process the background signal to balance contents of left and right channels of the background signal.

16. The computer-readable medium of claim 14, wherein the instructions also cause the processor to change the perceptual location of the output audio source from a current perceptual location in a background region to a new perceptual location in a foreground region, and wherein changing the perceptual location comprises:

changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of the new perceptual location;

changing foreground attenuation scalars in order to decrease attenuation of the foreground signal; and

changing background attenuation scalars in order to increase attenuation of the background signal.

17. The computer-readable medium of claim 14, wherein the instructions also cause the processor to change the perceptual location of the output audio source from a current perceptual location in a foreground region to a new perceptual location in a background region, and wherein changing the perceptual location comprises:

changing background control scalars to correspond to a background angle of the new perceptual location;

changing background attenuation scalars in order to decrease attenuation of the background signal; and

changing foreground attenuation scalars in order to increase attenuation of the foreground signal.

18. The computer-readable medium of claim 14, wherein the instructions also cause the processor to change the perceptual location of the output audio source within a foreground region by gradually changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of a new perceptual location.

19. The computer-readable medium of claim 14, wherein the instructions also cause the processor to change the perceptual location of the output audio source within a background region by gradually changing background control scalars to correspond to a background angle of a new perceptual location.

20. An apparatus for providing a distinct perceptual location for an audio source within an audio mixture, comprising:

means for processing a foreground signal to provide a foreground perceptual angle for the foreground signal;

means for processing the foreground signal to provide a desired attenuation level for the foreground signal;

means for processing a background signal that has been low-pass filtered to provide a background perceptual angle for the background signal;

means for processing the background signal to provide a desired attenuation level for the background signal, wherein the background signal is processed to sound more diffuse than the foreground signal, wherein attenuation is applied to a first background channel based on a sampling rate of a delay line applied to a second background channel; and

means for combining the foreground signal and the background signal into an output audio source.

21. The apparatus of claim 20, wherein an input audio source is a stereo audio source, and further comprising:

means for processing the foreground signal to balance contents of left and right channels of the foreground signal; and

means for processing the background signal to balance contents of left and right channels of the background signal.

22. The apparatus of claim 20, further comprising means for changing the perceptual location of the output audio source from a current perceptual location in a background region to a new perceptual location in a foreground region, the means for changing the perceptual location comprising:

means for changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of the new perceptual location;

means for changing foreground attenuation scalars in order to decrease attenuation of the foreground signal; and

means for changing background attenuation scalars in order to increase attenuation of the background signal.

23. The apparatus of claim 20, further comprising means for changing the perceptual location of the output audio source from a current perceptual location in a foreground region to a new perceptual location in a background region, the means for changing the perceptual location comprising:

means for changing background control scalars to correspond to a background angle of the new perceptual location;

means for changing background attenuation scalars in order to decrease attenuation of the background signal; and

means for changing foreground attenuation scalars in order to increase attenuation of the foreground signal.

24. The apparatus of claim 20, further comprising means for changing the perceptual location of the output audio source within a foreground region by gradually changing foreground angle control scalars and foreground mixing scalars to correspond to a foreground angle of a new perceptual location.

25. The apparatus of claim 20, further comprising means for changing the perceptual location of the output audio source within a background region by gradually changing background control scalars to correspond to a background angle of a new perceptual location.