Mixing techniques for mixing audio

• US 20070286426A1
• Filed: 06/07/2006
• Published: 12/13/2007
• Est. Priority Date: 06/07/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Xiang, Pei, Choy, Eddie L.T., Kulkarni, Prajakt V., Gupta, Samir Kumar
• Granted Patent: US 8,041,057 B2
• Time in Patent Office: Days
• US Class Current: 381/17
• CPC Class Codes: H04M 1/6016 in the receiver circuit
• CPC Class Codes: H04M 1/72442 for playing music files
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04S 7/30 Control circuits for electronic adaptation of the sound field

Abstract

This disclosure describes audio mixing techniques that intelligently combine two or more audio signals into an output signal. The techniques allow audio to be combined, yet create perceptual differentiation between the different audio signals. The result is that a user is able to hear both audio signals in a combined output, but the different audio signals do not perceptually interfere with one another. The techniques are relatively simple to implement and are well suited for radio telephones.

Claims

1. A method comprising:

receiving a first audio and a second audio;

applying a first positive gain to a first channel of the first audio;

applying a negative gain to a second channel of the first audio;

applying a second positive gain to a first channel of the second audio;

applying a third positive gain to a second channel of the second audio;

combining the first channel of the first audio with the first channel of the second audio; and

combining the second channel of the first audio with the second channel of the second audio.

2. The method of claim 1, wherein the first audio is music audio and the second audio signal is phone call audio associated with an incoming telephone call.

3. The method of claim 1, further comprising applying scalar functions to the first audio to change between foreground and background output for the first audio, wherein the scalar functions include:

a first front scalar function for the first channel of the first audio;

a second front scalar function for the second channel of the first audio;

a first back scalar function for the first channel of the first audio; and

a second back scalar function for the second channel of the first audio,

wherein the gains to the first audio are applied in a path that defines the background output.

4. The method of claim 3, wherein the scalar functions cause a perceptual change in the first audio from a front perceptual location to a back perceptual location in response to a change from a music mode to a phone call mode.

5. The method of claim 4, wherein in response to the change from the music mode to the phone call mode:

the first front scalar function for the first channel of the first audio changes foreground output for the first channel of the first audio from unity to zero;

the second front scalar function for the second channel of the first audio changes foreground output for the second channel of the first audio from unity to zero over a different time period than the front scalar function for the first channel of the first audio;

the first back scalar function for the first channel of the first audio changes background output for the first channel of the first audio from zero to unity;

the second back scalar function for the second channel of the first audio changes background output for the second channel of the first audio from zero to unity over a different time period than the back scalar function for the first channel of the first audio.

6. The method of claim 1, wherein the negative gain comprises a first negative gain, the method further comprising:

applying a second negative gain to a second path of the second channel of the first audio and adding the second path into the first channel of the first audio.

7. The method of claim 6, wherein:

the first positive gain to the first channel of the first audio is approximately 0.5;

the first negative gain to the second channel of the first audio is approximately −

0.12;

the second negative gain to the second path of the second channel of the first audio is approximately −

0.07;

the second positive gain to the first channel of the second audio is approximately 0.575; and

the third positive gain to the second channel of the second audio is approximately 0.818.

8. The method of claim 1, further comprising applying low pass filters to the first and second channels of the first audio.

9. The method of claim 1, further comprising delaying the second channel of the first audio.

10. The method of claim 1, wherein the first and second channels of the first audio comprise left and right stereo channels and wherein the second audio is a mono audio, the method further comprising defining the left and right channels of the second audio as copies of the mono audio.

11. The method of claim 1, wherein the first audio and the second audio are mono audio, the method further comprising defining the lift and right channels respectively for the first and second audio.

12. A method comprising:

receiving a music audio and a phone call audio, the music audio including first and second channels and the phone call audio including a mono channel;

applying scalar functions to the music audio to change a path of the music audio from a foreground path to a background path;

applying low pass filters to the first and second channels of the music audio in the background path;

delaying the second channel of the music audio in the background path;

applying a first positive gain to the first channel of the music audio in the background path;

applying a first negative gain to a first path of the second channel of the music audio in the background path;

applying a second negative gain to a second path of the second channel of the music audio in the background path;

adding the second path of the second channel of the music audio into the first channel of the music audio in the background path;

defining first and second channels for the phone call audio based on mono channel;

applying a second positive gain to a first channel of the phone call audio;

applying a third positive gain to a second channel of the phone call audio;

combining the first channel of the music audio in the background path with the first channel of the phone call audio; and

combining the second channel of the music audio in the background path with the second channel of the phone call audio.

13. The method of claim 12, further comprising applying scalar functions to the music audio to change between the foreground and background paths, wherein the scalar functions cause a perceptual change in the music audio from a front perceptual location to a back perceptual location in response to a change from a music mode to a phone call mode.

14. The method of claim 13, wherein applying scalar functions includes

applying a first front scalar function for the first channel of the music audio to change foreground output for the first channel of the music audio from unity to zero;

applying a second front scalar function for the second channel of the music audio to change foreground output for the second channel of the music audio from unity to zero over a different time period than the front scalar function for the first channel of the music audio;

applying a first back scalar function for the first channel of the music audio to change background output for the first channel of the music audio from zero to unity; and

applying a second back scalar function for the second channel of the music audio to change background output for the second channel of the music audio from zero to unity over a different time period than the back scalar function for the first channel of the music audio.

15. A computer readable medium comprising instructions that upon execution:

receive a first audio and a second audio;

apply a first positive gain to a first channel of the first audio;

apply a negative gain to a second channel of the first audio;

apply a second positive gain to a first channel of the second audio;

apply a third positive gain to a second channel of the second audio;

combine the first channel of the first audio with the first channel of the second audio; and

combine the second channel of the first audio with the second channel of the second audio.

16. The computer readable medium of claim 15, wherein the first audio is music audio and the second audio is phone call audio associated with an incoming telephone call.

17. The computer readable medium of claim 15, wherein the instructions apply scalar functions to the first audio to change between foreground and background output for the first audio, wherein the scalar functions include:

a first front scalar function for the first channel of the first audio;

a second front scalar function for the second channel of the first audio;

a first back scalar function for the first channel of the first audio; and

a second back scalar function for the second channel of the first audio,

wherein the gains to the first audio are applied in a path that defines the background output.

18. The computer readable medium of claim 17, wherein the scalar functions cause a perceptual change in the first audio from a front perceptual location to a back perceptual location in response to a change from a music mode to a phone call mode.

19. The computer readable medium of claim 18, wherein in response to the change from the music mode to the phone call mode:

the first front scalar function for the first channel of the first audio changes foreground output for the first channel of the first audio from unity to zero;

the second front scalar function for the second channel of the first audio changes foreground output for the second channel of the first audio from unity to zero over a different time period than the front scalar function for the first channel of the first audio;

the first back scalar function for the first channel of the first audio changes background output for the first channel of the first audio from zero to unity;

the second back scalar function for the second channel of the first audio changes background output for the second channel of the first audio from zero to unity over a different time period than the back scalar function for the first channel of the first audio.

20. The computer readable medium of claim 15, wherein the negative gain comprises a first negative gain, wherein the instructions:

apply a second negative gain to a second path of the second channel of the first audio and add the second path into the first channel of the first audio.

21. The computer readable medium of claim 20, wherein:

the first positive gain to the first channel of the first audio is approximately 0.5;

the first negative gain to the second channel of the first audio is approximately −

0.12;

the second negative gain to the second path of the second channel of the first audio is approximately −

0.07;

the second positive gain to the first channel of the second audio is approximately 0.575; and

the third positive gain to the second channel of the second audio is approximately 0.818.

22. The computer readable medium of claim 15, wherein the instructions apply low pass filters to the first and second channels of the first audio.

23. The computer readable medium of claim 15, wherein the instructions delay the second channel of the first audio.

24. The computer readable medium of claim 15, wherein the first and second channels of the first audio comprise left and right stereo channels and wherein the second audio is mono audio, and wherein the instructions define the left and right channels of the second audio as copies of the mono audio.

25. The computer readable medium of claim 15, wherein the first audio and the second audio are mono audio, and wherein the instructions define the left and right channels respectively for the first and second audio.

26. A device comprising:

an audio mixing unit that combines two or more audio signals to form an audio output, wherein the audio mixing unit;

receives a first audio signal and a second audio signal;

applies a first positive gain to a first channel of the first audio signal;

applies a negative gain to a second channel of the first audio signal;

applies a second positive gain to a first channel of the second audio signal;

applies a third positive gain to a second channel of the second audio signal;

combines the first channel of the first audio signal with the first channel of the second audio signal; and

combines the second channel of the first audio signal with the second channel of the second audio signal.

27. The device of claim 26, wherein the device comprises a radio telephone, and wherein the first audio signal is music audio and the second audio signal is phone call audio associated with an incoming telephone call, the device further comprising:

a music unit that generates the music audio;

a transmitter/receiver that receives a wireless communication; and

a modem that generates the phone call audio from the wireless communication.

28. The device of claim 26, wherein mixing unit applies scalar functions to the first audio signal to change between foreground and background output for the first audio signal, wherein the scalar functions include:

a first front scalar function for the first channel of the first audio signal;

a second front scalar function for the second channel of the first audio signal;

a first back scalar function for the first channel of the first audio signal; and

a second back scalar function for the second channel of the first audio signal,

wherein the gains to the first audio signal are applied in a path that defines the background output.

29. The device of claim 28, wherein the scalar functions cause a perceptual change in the first audio signal from a front perceptual location to a back perceptual location in response to a change from a music mode to a phone call mode.

30. The device of claim 29, wherein in response to the change from the music mode to the phone call mode:

the first front scalar function for the first channel of the first audio signal changes foreground output for the first channel of the first audio signal from unity to zero;

the second front scalar function for the second channel of the first audio signal changes foreground output for the second channel of the first audio signal from unity to zero over a different time period than the front scalar function for the first channel of the first audio signal;

the first back scalar function for the first channel of the first audio signal changes background output for the first channel of the first audio signal from zero to unity;

the second back scalar function for the second channel of the first audio signal changes background output for the second channel of the first audio signal from zero to unity over a different time period than the back scalar function for the first channel of the first audio signal.

31. The device of claim 26, wherein the negative gain comprises a first negative gain, wherein the mixing unit:

applies a second negative gain to a second path of the second channel of the first audio signal and add the second path into the first channel of the first audio signal.

32. The device of claim 31, wherein:

the first positive gain to the first channel of the first audio signal is approximately 0.5;

the first negative gain to the second channel of the first audio signal is approximately −

0.12;

the second negative gain to the second path of the second channel of the first audio signal is approximately −

0.07;

the second positive gain to the first channel of the second audio signal is approximately 0.575; and

the third positive gain to the second channel of the second audio signal is approximately 0.818.

33. The device of claim 26, wherein the mixing unit applies low pass filters to the first and second channels of the first audio signal.

34. The device of claim 26, wherein the mixing unit delays the second channel of the first audio signal.

35. The device of claim 26, wherein the first and second channels of the first audio signal comprise left and right channels and wherein the second audio signal is a mono audio signal, and wherein the mixing unit defines the left and right channels of the second audio signal as copies of the mono audio signal.

36. The device of claim 26, wherein the first audio signal and the second audio signal are mono audio signals, and wherein the mixing unit defines the left and right channels respectively for the first and second audio signals.

37. The device of claim 26, further comprising:

speakers; and

a drive circuit that receives combined signals for the first and second channels and generates drive signals to drive the speakers.

38. The device of claim 26, wherein the first and second audio signals comprise one of:

digital signals; and

analog signals.

39. A device comprising:

means for receiving a music audio signal and a phone call audio signal, the music audio signal including first and second channels and the phone call audio signal including a mono channel;

means for applying scalar functions to the music audio signal to change a path of the music audio signal from a foreground path to a background path;

means for applying low pass filters to the first and second channels of the music audio signal in the background path;

means for delaying the second channel of the music audio signal in the background path;

means for applying a first positive gain to the first channel of the music audio signal in the background path;

means for applying a first negative gain to a first path of the second channel of the music audio signal in the background path;

means for applying a second negative gain to a second path of the second channel of the music audio signal in the background path;

means for adding the second path of the second channel of the music audio signal into the first channel of the music audio signal in the background path;

means for defining first and second channels for the phone call audio signal based on mono channel;

means for applying a second positive gain to a first channel of the phone call audio signal;

means for applying a third positive gain to a second channel of the phone call audio signal;

means for combining the first channel of the music audio signal in the background path with the first channel of the phone call audio signal; and

means for combining the second channel of the music audio signal in the background path with the second channel of the phone call audio signal.

40. The device of claim 39, further comprising means for applying scalar functions to the music audio signal to change between the foreground and background paths, wherein the scalar functions cause a perceptual change in the music audio signal from a front perceptual location to a back perceptual location in response to a change from a music mode to a phone call mode.

41. The device of claim 39, wherein means for applying scalar include:

means for applying a first front scalar function for the first channel of the music audio signal to change foreground output for the first channel of the music audio signal from unity to zero;

means for applying a second front scalar function for the second channel of the music audio signal to change foreground output for the second channel of the music audio signal from unity to zero over a different time period than the front scalar function for the first channel of the music audio signal;

means for applying a first back scalar function for the first channel of the music audio signal to change background output for the first channel of the music audio signal from zero to unity; and

means for applying a second back scalar function for the second channel of the music audio signal to change background output for the second channel of the music audio signal from zero to unity over a different time period than the back scalar function for the first channel of the music audio signal.

42. A device comprising an audio mixing unit that:

receives first audio information including first and second stereo channels;

generates first foreground audio output based on the first audio information;

receives second audio information;

applies gains to the first and second stereo channels to generate background audio output;

generates second foreground audio output based on the second audio information; and

combines the second foreground audio output with the background audio output to generate combined output for the first and second audio information.

43. The device of claim 42, wherein the mixing unit uses scaling, filtering, delay, and channel combination to generate the background audio output.

44. A device comprising an audio mixing unit that:

receives music audio;

presents the music audio to a user;

receives telephone call audio;

mixes the music audio and the telephone call audio so that the music audio is background audio and the telephone call audio is foreground audio, including applying gains to the music audio to create a background perception; and

presents a combination of the music audio with the telephone audio as a combined output with the music in the background and the telephone call in the foreground.

45. The device of claim 44, wherein the mixing unit uses scaling, filtering, delay, and channel combination to generate the background perception for the music audio.