SYSTEMS, METHODS, AND APPARATUS FOR FRAME ERASURE RECOVERY

• US 20110082693A1
• Filed: 12/13/2010
• Published: 04/07/2011
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kandhadai, Ananthapadmanbhan A., Krishnan, Venkatesh
• Granted Patent: US 8,825,477 B2
• Time in Patent Office: Days
• US Class Current: 704/225
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm

Abstract

In one configuration, erasure of a significant frame of a sustained voiced segment is detected. An adaptive codebook gain value for the erased frame is calculated based on the preceding frame. If the calculated value is less than (alternatively, not greater than) a threshold value, a higher adaptive codebook gain value is used for the erased frame. The higher value may be derived from the calculated value or selected from among one or more predefined values.

Claims

1. A method of processing an encoded speech signal, said method comprising:

detecting at least one particular sequence of modes in the two frames of the encoded speech signal that precede a frame erasure;

obtaining a gain value based at least in part on the frame of the encoded speech signal before the erasure;

in response to said detecting, comparing the obtained gain value to a threshold value;

in response to a result of said comparing, increasing the obtained gain value; and

based on the increased gain value, generating an excitation signal for the erased frame.

2. A method according to claim 1, wherein said detecting comprises detecting the sequence (nonvoiced frame, voiced frame) in the two frames of the encoded speech signal that precede the frame erasure.

3. A method according to claim 1, wherein said detecting comprises detecting the sequence (frame having a nonperiodic excitation, frame having an adaptive and periodic excitation) in the two frames of the encoded speech signal that precede the frame erasure.

4. A method according to claim 1, wherein said detecting comprises detecting the sequence (frame encoded using noise-excited linear prediction, frame encoded using code-excited linear prediction) in the two frames of the encoded speech signal that precede the frame erasure.

5. A method according to claim 1, wherein said detecting comprises detecting the sequence (silence descriptor frame, voiced frame) in the two frames of the encoded speech signal that precede the frame erasure.

6. A method according to claim 1, wherein the obtained gain value is an adaptive codebook gain value predicted for the erased frame.

7. A method according to claim 1, wherein said calculating an excitation signal for the erased frame includes multiplying a sequence of values which is based on the frame of the encoded speech signal that precedes the frame erasure by the increased gain value.

8. A computer-readable medium comprising instructions which when executed by an array of logic elements cause the array to perform a method according to claim 1.

9. An apparatus for processing an encoded speech signal, said apparatus comprising:

means for detecting at least one particular sequence of modes in the two frames of the encoded speech signal that precede a frame erasure;

means for obtaining a gain value, based at least in part on the frame of the encoded speech signal before the erasure;

means for comparing the obtained gain value to a threshold value, in response to detection of the at least one particular sequence of modes by said means for detecting;

means for increasing the obtained gain value, in response to a result of the comparison by said means for comparing; and

means for calculating an excitation signal for the erased frame, based on the increased gain value.

10. An apparatus according to claim 9, wherein said means for detecting is configured to detect the sequence (nonvoiced frame, voiced frame) in the two frames of the encoded speech signal that precede the frame erasure.

11. An apparatus according to claim 9, wherein said means for detecting is configured to detect the sequence (frame having a nonperiodic excitation, frame having an adaptive and periodic excitation) in the two frames of the encoded speech signal that precede the frame erasure.

12. An apparatus according to claim 9, wherein said means for detecting is configured to detect the sequence (frame encoded using noise-excited linear prediction, frame encoded using code-excited linear prediction) in the two frames of the encoded speech signal that precede the frame erasure.

13. An apparatus according to claim 9, wherein said means for detecting is configured to detect the sequence (silence descriptor frame, voiced frame) in the two frames of the encoded speech signal that precede the frame erasure.

14. An apparatus according to claim 9, wherein the obtained gain value is an adaptive codebook gain value predicted for the erased frame.

15. An apparatus according to claim 9, wherein said means for calculating an excitation signal for the erased frame is configured to multiply a sequence of values which is based on the frame of the encoded speech signal that precedes the frame erasure by the increased gain value.