Open-loop pitch track smoothing

• US 8,386,245 B2
• Filed: 10/27/2006
• Issued: 02/26/2013
• Est. Priority Date: 03/20/2006
• Status: Active Grant

• Current Assignee: MACOM Technology Solutions Holdings, Inc.
• Original Assignee: Mindspeed Technologies Inc. (MACOM Technology Solutions Holdings, Inc.)
• Inventors: Gao, Yang
• Primary Examiner(s): WOZNIAK, JAMES S
• Application Number:
  US12/224,003
• Publication Number:
  US 20100241424A1
• Time in Patent Office: 2,314 Days
• Field of Search: 704/201, 704205-207, 704/216
• US Class Current: 704/207
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

There is provided a speech encoder for performing an algorithm that comprises obtaining (205) a plurality of open-loop pitch candidates from a current frame of a speech signal, the plurality of open-loop pitch candidates including a first open-loop pitch candidate and a second open-loop pitch candidate; obtaining (205) a voicing information from one or more previous frames; and selecting (280) one of the plurality of open-loop pitch candidates as a final pitch of the current frame using the voicing information from the one or more previous frames. In one aspect, the voicing information from the one or more previous frames includes a previous pitch of the one or more previous frames. In a further aspect, selecting the final pitch of the current frame includes selecting (210) an initial open-loop pitch from that has the maximum long-term correlation value.

Claims

1. A method of performing an open-loop pitch analysis using a circuitry, the method comprising:

obtaining, using the circuitry, a plurality of open-loop pitch candidates including a first open-loop pitch candidate (p_max1), a second open-loop pitch candidate (p_max2) and a third open-loop pitch candidate (p_max3), wherein p_max1>

p_max2>

p^—

max3;

obtaining, using the circuitry, a plurality of long-term correlation values, including a first correlation value (max1), a second correlation value (max2) and a third correlation value (max3), for each corresponding one of the plurality of open-loop pitch candidates;

selecting, using the circuitry, an initial open-loop pitch (max) from the plurality of open-loop pitch candidates, wherein the long-term correlation value corresponding to max (p_max) has the maximum long-term correlation value among the long-term correlation values;

if p_max2 is less than p_max,

setting a first threshold value to a first pre-determined threshold value if an absolute value of a previous pitch less p_max2 is less than a first pre-determined comparison value and setting the first threshold value to a second pre-determined threshold value if the absolute value of the previous pitch less p_max2 is not less than the first pre-determined comparison value;

if max multiplied by the first threshold value is less than max2, setting max to max2 and p_max to p^—

max2;

if p_max3 is less than p_max,

setting a second threshold value to a third pre-determined threshold value if an absolute value of a previous pitch less p_max3 is less than a second pre-determined comparison value and setting the second threshold value to a fourth pre-determined threshold value if the absolute value of the previous pitch less p_max3 is not less than the second pre-determined comparison value; and

if max multiplied by the second threshold value is less than max3, setting p_max to p_max3.

2. The method of claim 1, wherein the first pre-determined comparison value is 10, the first pre-determined threshold value is 0.7 and the second pre-determined threshold value is 0.9.

3. The method of claim 2, wherein the second pre-determined comparison value is 5, the third pre-determined threshold value is 0.7 and the fourth pre-determined threshold value is 0.9.

4. The method of claim 1, wherein the previous pitch is from one or more previous frames.

5. The method of claim 1, wherein the previous pitch is from an immediate previous frame.

6. A speech encoder for performing an open-loop pitch analysis, the speech encoder comprising:

a controller configured to;

obtain a plurality of open-loop pitch candidates including a first open-loop pitch candidate (p_max1), a second open-loop pitch candidate (p_max2) and a third open-loop pitch candidate (p_max3), wherein p_maxl>

p_max2>

p_max3;

obtain a plurality of long-term correlation values, including a first correlation value (max1), a second correlation value (max2) and a third correlation value (max3), for each corresponding one of the plurality of open-loop pitch candidates;

select an initial open-loop pitch (max) from the plurality of open-loop pitch candidates, wherein the long-term correlation value corresponding to max (p_max) has the maximum long-term correlation value among the long-term correlation values;

if p_max2 is less than p_max,

set a first threshold value to a first pre-determined threshold value if an absolute value of a previous pitch less p_max2 is less than a first pre-determined comparison value and set the first threshold value to a second pre-determined threshold value if the absolute value of the previous pitch less p_max2 is not less than the first pre-determined comparison value;

if max multiplied by the first threshold value is less than max2, set max to max2 and p_max to p_max2;

if p_max3 is less than p_max,

set a second threshold value to a third pre-determined threshold value if an absolute value of a previous pitch less p max3 is less than a second pre-determined comparison value and set the second threshold value to a fourth pre-determined threshold value if the absolute value of the previous pitch less p_max3 is not less than the second pre-determined comparison value; and

if max multiplied by the second threshold value is less than max3, set p_max to p_max3.

7. The speech encoder of claim 6, wherein the first pre-determined comparison value is 10, the first pre-determined threshold value is 0.7 and the second pre-determined threshold value is 0.9.

8. The speech encoder of claim 7, wherein the second pre-determined comparison value is 5, the third pre-determined threshold value is 0.7 and the fourth pre-determined threshold value is 0.9.

9. The speech encoder of claim 6, wherein the previous pitch is from one or more previous frames.

10. The speech encoder of claim 6, wherein the previous pitch is from an immediate previous frame.

11. A method of performing an open-loop pitch analysis, using a circuitry, the method comprising:

obtaining, using the circuitry, a plurality of open-loop pitch candidates including a first open-loop pitch candidate (p_max1), a second open-loop pitch candidate (p_max2) and a third open-loop pitch candidate (p_max3), wherein p_max1>

p_max2>

p_max3;

obtaining, using the circuitry, a plurality of long-term correlation values, including a first correlation value (max1), a second correlation value (max2) and a third correlation value (max3), for each corresponding one of the plurality of open-loop pitch candidates;

selecting, using the circuitry, an initial open-loop pitch (max) from the plurality of open-loop pitch candidates, wherein the long-term correlation value corresponding to max (p_max) has the maximum long-term correlation value among the long-term correlation values;

if p_max2 is less than p_max, setting max to max2 and p_max to p_max2 based on a first decision; and

if p_max3 is less than p_max, setting p_max to p_max3 based on a second decision.

12. The method of claim 11 further comprising:

obtaining a voicing information from one or more previous frames; and

using the voicing information from the one or more previous frames for each of the first decision and the second decision.

13. The method of claim 12, wherein the voicing information from the one or more previous frames includes a previous pitch of the one or more previous frames.

14. The method of claim 12, wherein the voicing information from the one or more previous frames is a pitch from an immediate previous frame.

15. The method of claim 11, where the first decision including:

setting a first threshold value to a first pre-determined threshold value if an absolute value of a previous pitch less p_max2 is less than a first pre-determined comparison value and setting the first threshold value to a second pre-determined threshold value if the absolute value of the previous pitch less p_max2 is not less than the first pre-determined comparison value; and

determining if max multiplied by the first threshold value is less than max2.

16. The method of claim 15, wherein the first pre-determined comparison value is 10, the first pre-determined threshold value is 0.7 and the second pre-determined threshold value is 0.9.

17. A speech encoder for performing an open-loop pitch analysis, the speech encoder comprising:

a controller configured to;

obtain a plurality of open-loop pitch candidates including a first open-loop pitch candidate (p_max1), a second open-loop pitch candidate (p_max2) and a third open-loop pitch candidate (p_max3), wherein p_max2>

p_max2>

p_max3;

obtain a plurality of long-term correlation values, including a first correlation value (max1), a second correlation value (max2) and a third correlation value (max3), for each corresponding one of the plurality of open-loop pitch candidates;

select an initial open-loop pitch (max) from the plurality of open-loop pitch candidates, wherein the long-term correlation value corresponding to max (p_max) has the maximum long-term correlation value among the long-term correlation values;

if p_max2 is less than p_max, set max to max2 and p_max to p_Max2 based on a first decision; and

if p_max3 is less than p_max, set p_max to p_max3 based on a second decision.

18. The speech encoder of claim 17, wherein the controller is further configured to:

obtain a voicing information from one or more previous frames; and

use the voicing information from the one or more previous frames for each of the first decision and the second decision.

19. The speech encoder of claim 18, wherein the voicing information from the one or more previous frames includes a previous pitch of the one or more previous frames.

20. The speech encoder of claim 18, wherein the voicing information from the one or more previous frames is a pitch from an immediate previous frame.

21. The speech encoder of claim 17, where the first decision including:

setting a first threshold value to a first pre-determined threshold value if an absolute value of a previous pitch less p_max2 is less than a first pre-determined comparison value and setting the first threshold value to a second pre-determined threshold value if the absolute value of the previous pitch less p_max2 is not less than the first pre-determined comparison value; and

determining if max multiplied by the first threshold value is less than max2.

22. The speech encoder of claim 21, wherein the first pre-determined comparison value is 10, the first pre-determined threshold value is 0.7 and the second pre-determined threshold value is 0.9.