SELECTION OF ENCODING MODES AND/OR ENCODING RATES FOR SPEECH COMPRESSION WITH OPEN LOOP RE-DECISION

• US 20070219787A1
• Filed: 01/22/2007
• Published: 09/20/2007
• Est. Priority Date: 01/20/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Manjunath, Sharath, Kandhadai, Ananthapadmanabhan, Choy, Eddie
• Granted Patent: US 8,090,573 B2
• Time in Patent Office: Days
• US Class Current: 704/207
• CPC Class Codes: G10L 19/22 Mode decision, i.e. based on audio signal content versus external parameters

Abstract

In a device configurable to encode speech performing an open loop re-decision may comprise representing a speech signal by amplitude components and phase components for a current frame and a past frame. During the current frame, there may be an extraction of uncompressed amplitude components and uncompressed phase components. The amplitude components and the phase components from the past frame may then be retrieved. A set of features may be generated based on the uncompressed amplitude components from the current frame, the uncompressed phase components from the current frame, the amplitude components from the past frame, and the phase components from the past frame. The set of features may be checked as part of the open loop re-decision, and determining a final encoding decision based on the checking may be performed. The final encoding decision may be an encoding mode and/or encoding rate.

Claims

1. In a device configurable to encode speech, a method to perform an open loop re-decision comprising:

representing a speech signal by amplitude components and phase components for a current frame and a past frame;

extracting uncompressed amplitude components and uncompressed phase components for a current frame;

retrieving the amplitude components and the phase components from the past frame;

generating a first set of features based on the uncompressed amplitude components from the current frame, the uncompressed phase components from the current frame, the amplitude components from the past frame, and the phase components from the past frame;

checking the first set of features as part of the open loop re-decision; and

determining a final encoding decision based on the checking.

2. The method of claim 1, wherein the final encoding decision is an encoding mode.

3. The method of claim 2, wherein the encoding mode changes from PPP to CELP.

4. The method of claim 1, wherein the final encoding decision is an encoding rate.

5. The method of claim 4, wherein the encoding rate changes from quarter to full.

6. The method of claim 4, wherein the encoding rate changes from half to full.

7. The method of claim 1, wherein the generating the first set of features further comprises calculating at least one energy ratio, calculating at least one signal to noise-ratio and calculating at least one correlation.

8. The method of claim 7, wherein the calculating at least one energy ratio further comprises at least one energy ratio calculated in the time domain, frequency domain, or perceptually weighted domain.

9. The method of claim 8, wherein the at least one energy ratio is calculated from a derived signal from the speech signal.

10. The method of claim 9, wherein the derived signal is a residual signal.

11. The method of claim 1, wherein the amplitude components from the past frame are compressed and the phase components from the past frame are compressed.

12. The method of claim 1, wherein the amplitude components from the past frame are uncompressed and the phase components from the past frame are uncompressed.

13. The method of claim 1, wherein the amplitude components from the past frame are compressed and the phase components from the past frame are uncompressed.

14. The method of claim 1, wherein the amplitude components from the past frame are uncompressed and the phase components from the past frame are compressed.

15. The method of claim 1, wherein the representing a speech signal by amplitude and phase components comprises calculating a fourier series and extracting real and imaginary parts of the fourier series to calculate the amplitude components and the phase components.

16. The method of claim 1, wherein checking the first set features further comprises checking at least one feature with at least one or more rules in a set of decision rules.

24. An apparatus comprising an array of logic elements configured to perform a method according to any of claims 1 to 16.

25. A mobile device according to claim 24, the mobile device comprising circuitry configured to interact with a network for cellular radio-frequency communications.

17. A computer-readable medium comprising storing a set of instructions, wherein the set of instructions when executed by one or more processors comprises:

means for representing a speech signal by amplitude components and phase components for a current frame and a past frame;

means for extracting uncompressed amplitude components and uncompressed phase components for the current frame;

means for retrieving amplitude components and phase components from a past frame;

means for generating a first set of features based on the uncompressed amplitude components from the current frame, the uncompressed phase components from the current frame, the amplitude components from the past frame, and the phase components from the past frame;

means for checking the first set of features as part of the open loop re-decision; and

means for determining a final encoding decision based on the means for checking.

18. The computer-readable medium of claim 17, wherein the final encoding decision is an encoding mode.

19. The computer-readable medium of claim 18, wherein the encoding mode changes from PPP to CELP.

20. The computer-readable medium of claim 19, wherein the final encoding decision is an encoding rate.

21. The computer-readable medium of claim 20, wherein the encoding rate changes from quarter to full.

22. The computer-readable medium of claim 21, wherein the encoding rate changes from half to full.

23. The computer-readable medium of claim 17, wherein the generating the first set of features further comprises calculating at least one energy ratio, at least one signal to noise-ratio and calculating at least one correlation.

26. A device configurable to encode speech and perform an open loop-redicision comprising:

means for representing a speech signal by amplitude components and phase components for a current frame and a past frame;

means for extracting uncompressed amplitude components and uncompressed phase components for a current frame;

means for retrieving the amplitude components and the phase components from the past frame;

means for generating a first set of features based on the uncompressed amplitude components from the current frame, the uncompressed phase components from the current frame, the amplitude components from the past frame, and the phase components from the past frame;

means for checking the first set of features as part of the open loop re-decision; and

means for determining a final encoding decision based on the checking.

27. The device of claim 26, wherein the means for determining the final encoding decision is an encoding mode.

28. The device of claim 27, wherein the encoding mode changes from PPP to CELP.

29. The device of claim 28, wherein the means for determining the final encoding decision is an encoding rate.

30. The device of claim 29, wherein the encoding rate changes from quarter to full.

31. The device of claim 30, wherein the encoding rate changes from half to full.

32. The device of claim 26, wherein the means for generating the first set of features further comprises means for calculating at least one energy ratio, means for calculating at least one signal-to-noise-ratio and means for calculating at least one correlation.

33. The device of claim 32, wherein the means for calculating at least one energy ratio, means for calculating at least one signal to noise-ratio, or means for calculating at least one correlation further comprises means for calculating in the time domain, frequency domain, or perceptually weighted domain.

34. The device of claim 33, wherein the at least one energy ratio, the at least one signal-to-noise-ratio, and the at least one correlation is calculated from a derived signal from the speech signal.

35. The device of claim 34, wherein the derived signal is a residual signal.

36. The device of claim 26, wherein the amplitude components from the past frame are compressed and the phase components from the past frame are compressed.

37. The device of claim 26, wherein the amplitude components from the past frame are uncompressed and the phase components from the past frame are uncompressed.

38. The device of claim 26, wherein the amplitude components from the past frame are compressed and the phase components from the past frame are uncompressed.

39. The device of claim 26, wherein the amplitude components from the past frame are uncompressed and the phase components from the past frame are compressed.

40. The device of claim 26, wherein the means for representing a speech signal by amplitude and phase components comprises means for calculating a fourier series and means for extracting real and imaginary parts of the fourier series to calculate the amplitude components and the phase components.

41. The device of claim 26, wherein the means for checking the first set features further comprises means for checking at least one feature with at least one or more rules in a set of decision rules.