Methods and devices for selectively generating time-scaled sound signals

• US 7,366,659 B2
• Filed: 06/07/2002
• Issued: 04/29/2008
• Est. Priority Date: 06/07/2002
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Etter, Walter
• Primary Examiner(s): Azad; Abul K.
• Application Number:
  US10/163,356
• Publication Number:
  US 20030229490A1
• Time in Patent Office: 2,153 Days
• Field of Search: None
• US Class Current: 704/211
• CPC Class Codes: G10L 21/04 Time compression or expansion

Abstract

Time-scaled, sound signals (i.e. sounds output at differing speeds) are generated by mixing weighted time-and frequency-domain processed signals, the former signal generally representing speech-based signals while the latter representing music-based signals. The weights applied to each type of signal may be determined by a scaling factor, which in turn is related to the desired speed at which a listener desires to hear a sound signal. In one example of the invention, only stationary signal portions of an input sound signal are used to generate time-scaled processed signals. An adaptive frame-size may also be used to pre-process the separate signals prior to being weighted, which at least decreases the amount of unwanted reverberative sound qualities in a resulting sound signal. Together, techniques envisioned by the present invention produce improved, speed adjusted sound signals.

Claims

1. A device for selectively generating time-scaled sound signals comprising:

a control unit adapted to generate first and second weights from an input sound signal;

a time-domain processor adapted to generate a time-domain processed, time-scaled signal (“

first signal”

);

a frequency-domain processor adapted to generate a frequency-domain processed, time domain, time-scaled signal (“

second signal”

) using an adaptive frame-size based on stationary and non-stationary characteristics of the input sound signal; and

a mixer adapted to adjust the first signal using the first weight, adjust the second signal using the second weight, combine the adjusted signals and output a time-scaled, sound signal.

2. The device as in claim 1 wherein the control unit is further adapted to adjust the first and second weights based on a scaling factor.

3. The device as in claim 2 wherein the control unit is further adapted to increase the first weight and decrease the second weight as the scaling factor increases.

4. The device as in claim 1 wherein the control unit comprises a sound discriminator adapted to detect whether the input sound signal is substantially a music or speech signal.

5. The device as in claim 1 wherein the frequency domain processor is adapted to generate a shortened frame-size for non-stationary portions of the input signal and to generate a lengthened frame-size for stationary portions of the input signal.

6. The device as in claim 1 wherein the frequency-domain processor is further adapted to generate a time-scaled signal only for stationary signal portions of the input signal.

7. The device as in claim 6 wherein the frequency-domain processor is further adapted to generate a second signal for non-stationary signal portions of the input signal which has substantially the same characteristics as the input signal.

8. The device as in claim 1 wherein the frequency-domain processor comprises a delay section adapted to add a delay to the second signal.

9. The device as in claim 1 wherein the time-domain processor is further adapted to output the first signal using an adaptive frame size based on pitch characteristics of the input sound signal.

10. The device as in claim 9 wherein the time-domain processor further comprises a pitch detector adapted to detect the pitch characteristics of the input sound signal.

11. The device as in claim 1 wherein the time-domain processor comprises a delay section adapted to add a delay to the first signal.

12. The device as in claim 1 wherein each of the processors comprises a delay section, wherein one of the delay sections is adapted to control a delay generated by the other delay section.

13. The device as in claim 1 wherein the mixer is further adapted to output a first signal when the input sound signal comprises substantially speech only.

14. The device as in claim 1 wherein the mixer is further adapted to output a second signal when the input sound signal comprises substantially music only.

15. A method for generating time-scaled sound signals comprising:

generating first and second weights from an input sound signal;

generating a time-domain processed, time-scaled signal (“

first signal”

);

generating a frequency-domain processed, time-domain, time-scaled signal (“

second signal”

) using an adaptive frame-size based on stationary and non-stationary characteristics of the input sound signal;

adjusting the first signal using the first weight;

adjusting the second signal using the second weight;

combining the adjusted signals; and

outputting a time-scaled, sound signal.

16. The method as in claim 15 further comprising adjusting the first and second weights based on a scaling factor.

17. The method as in claim 16 further comprising increasing the first weight and decreasing the second weight as the scaling factor increases.

18. The method as in claim 15 further comprising detecting whether the input sound signal is substantially a music or speech signal.

19. The method as in claim 15 further comprising generating a shortened frame size for non-stationary characteristics and generating a lengthened frame-size for stationary characteristics.

20. The method as in claim 15 further comprising generating a time-scaled signal only for stationary portions of the input sound signal.

21. The method as in claim 20 further comprising generating a second signal for the non-stationary portions of the input sound signal which has substantially the same characteristics as the input signal.

22. The method as in claim 15 further comprising adding a delay to the first signal.

23. The method as in claim 15 further comprising generating a frame-size based on pitch characteristics of the input sound signal.

24. The method as in claim 15 further comprising adding a delay to the second signal.

25. The method as in claim 15 further comprising controlling delays added to the first and second signals to ensure the signals are substantially synchronized.

26. The method as in claim 15 further comprising outputting a first signal when the input sound signal comprises substantially speech only.

27. The method as in claim 15 further comprising outputting a second signal when the input sound signal comprises substantially music only.