Classification-based frame loss concealment for audio signals

• US 20070118369A1
• Filed: 11/23/2005
• Published: 05/24/2007
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Chen, Juin-Hwey
• Granted Patent: US 7,805,297 B2
• Time in Patent Office: Days
• US Class Current: 704/229
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm

Abstract

A system and method for performing frame loss concealment (FLC) when portions of a bit stream representing an audio signal are lost within the context of a digital communication system. The system and method utilizes a plurality of different FLC techniques, wherein each technique is tuned or designed for a different kind of audio signal. When a frame is lost, a previously-decoded audio signal corresponding to one or more previously-received good frames is analyzed. Based on the result of the analysis, the FLC technique that is most likely to perform well for the previously-decoded audio signal is chosen to perform the FLC operation for the current lost frame. In one implementation, the plurality of different FLC techniques include an FLC technique designed for music, such as a frame repeat FLC technique, and an FLC technique designed for speech, such as a periodic waveform extrapolation (PWE) technique.

Claims

1. A method in an audio decoder for generating an output audio signal corresponding to a lost frame of an audio bit-stream, comprising:

analyzing at least a portion of a previously-decoded audio signal corresponding to previously-decoded frames of the audio bit-stream;

selecting one of a plurality of frame loss concealment (FLC) techniques based on the results of the analysis; and

applying the selected one of the plurality of FLC techniques to the previously-decoded audio signal to generate the output audio signal corresponding to the lost frame.

2. The method of claim 1, wherein analyzing at least a portion of a previously-decoded audio signal comprises determining if the previously-decoded audio signal is speech or music.

3. The method of claim 1, wherein analyzing at least a portion of a previously-decoded audio signal comprises determining if a periodicity measure associated with the previously-decoded audio signal exceeds a predefined threshold.

4. The method of claim 2, wherein analyzing at least a portion of a previously-decoded audio signal further comprises determining if a periodicity measure associated with the previously-decoded audio signal exceeds a predefined threshold.

5. The method of claim 1, wherein selecting one of a plurality of FLC techniques based on the results of the analysis comprises selecting an FLC technique designed for music.

6. The method of claim 5, wherein selecting an FLC technique designed for music comprises selecting a frame repeat FLC technique.

7. The method of claim 1, wherein selecting one of a plurality of FLC techniques based on the results of the analysis comprises selecting an FLC technique designed for speech.

8. The method of claim 7, wherein selecting an FLC technique designed for speech comprises selecting a periodic waveform extrapolation (PWE) based FLC technique.

9. An audio decoding system, comprising:

a decoded signal buffer that stores a previously-decoded audio signal corresponding to previously-decoded frames of an audio bit-stream;

a plurality of processing blocks coupled to the decoded signal buffer, each of the plurality of processing blocks configured to perform a corresponding frame loss concealment (FLC) technique;

a signal classifier coupled to the decoded signal buffer and the plurality of processing blocks, the signal classifier configured to analyze at least a portion of the previously-decoded audio signal stored in the decoded signal buffer and, based on the results of the analysis, to select one of the plurality of processing blocks to perform FLC operations on the previously-decoded audio signal, thereby generating an output audio signal corresponding to a lost frame of the audio bit-stream.

10. The audio decoding system of claim 9, wherein the signal classifier is configured to determine if the previously-decoded audio signal is speech or music.

11. The audio decoding system of claim 9, wherein the signal classifier is configured to determine if a periodicity measure associated with the previously-decoded audio signal exceeds a predefined threshold.

12. The audio decoding system of claim 9, wherein the signal classifier is further configured to determine if a periodicity measure associated with the previously-decoded audio signal exceeds a predefined threshold.

13. The audio decoding system of claim 9, wherein one of the plurality of processing blocks is configured to perform an FLC technique designed for music.

14. The audio decoding system of claim 13, wherein the one of the plurality of processing blocks configured to perform an FLC technique designed for music is configured to perform a frame repeat FLC technique.

15. The audio decoding system of claim 9, wherein one of the plurality of processing blocks is configured to perform an FLC technique designed for speech.

16. The audio decoding system of claim 15, wherein the one of the plurality of processing blocks configured to perform an FLC technique designed for speech is configured to perform a periodic waveform extrapolation (PWE) based FLC technique.

17. A computer program product comprising a computer useable medium having computer program logic recorded thereon for enabling a processor in a computer system to generate an output audio signal corresponding to a lost frame of an audio bit-stream, comprising:

first means for enabling the processor to analyze at least a portion of a previously-decoded audio signal corresponding to previously-decoded frames of the audio bit-stream;

second means for enabling the processor to select one of a plurality of frame loss concealment (FLC) techniques based on the results of the analysis; and

third means for enabling the processor to apply the selected one of the plurality of FLC techniques to the previously-decoded audio signal to generate the output audio signal corresponding to the lost frame.

18. The computer program product of claim 17, wherein the first means includes means for enabling the processor to determine if the previously-decoded audio signal is speech or music.

19. The computer program product of claim 17, wherein the first means includes means for enabling the processor to determine if a periodicity measure associated with the previously-decoded audio signal exceeds a predefined threshold.

20. The computer program product of claim 18, wherein the first means further includes means for enabling the processor to determine if a periodicity measure associated with the previously-decoded audio signal exceeds a predefined threshold.

21. The computer program product of claim 17, wherein the second means comprises means for enabling the processor to select an FLC technique designed for music.

22. The computer program product of claim 21, wherein the means for enabling the processor to select an FLC technique designed for music comprises means for enabling the processor to select a frame repeat FLC technique.

23. The computer program product of claim 17, wherein the second means comprises means for enabling the processor to select an FLC technique designed for speech.

24. The computer program product of claim 23, wherein the means for enabling the processor to select an FLC technique designed for speech comprises means for enabling the processor to select a periodic waveform extrapolation (PWE) based FLC technique.