Error Concealment

• US 20100281321A1
• Filed: 05/01/2009
• Published: 11/04/2010
• Est. Priority Date: 05/01/2009
• Status: Active Grant

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: Cambridge Silicon Radio Limited (Qualcomm, Inc.)
• Inventors: Plude, Scott, Sun, Xuejing, Gadre, Sameer
• Granted Patent: US 8,316,267 B2
• Time in Patent Office: Days
• US Class Current: 714/747
• CPC Class Codes: G06F 11/08 Error detection or correction by redundancy in data representation, e.g. by using checking codes
• CPC Class Codes: H04L 1/0047 Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data

Abstract

A method and apparatus for selectively replacing damaged portions of a data stream. The method comprises analyzing the data stream to identify damaged portions therein; selecting a damaged portion for replacement; and replacing the selected damaged portion. The selected damaged portion is selected for replacement in dependence on a rate of replacement, the rate of replacement being that at which previous portions of the data stream have been replaced.

Claims

1. A method of selectively replacing damaged portions of a data stream, comprising:

analyzing the data stream to identify damaged portions therein;

selecting a damaged portion for replacement; and

replacing the selected damaged portion;

wherein the selected damaged portion is selected for replacement in dependence on a rate of replacement, the rate of replacement being that at which previous portions of the data stream have been replaced.

2. A method as claimed in claim 1, comprising replacing the selected damaged portion with a replacement portion by replacing at least one sample of the selected damaged portion.

3. A method as claimed in claim 1, further comprising assigning a portion replacement value to each portion of the data stream, wherein the rate of replacement associated with the selected damaged portion is a weighted average of a previous rate of replacement associated with the portion previous to the selected damaged portion and the portion replacement value of the portion previous to the selected damaged portion.

4. A method as claimed in claim 3, comprising assigning a first portion replacement value to portions of the data stream that are replaced, and assigning a second portion replacement value to portions of the data stream that are not replaced.

5. A method as claimed in claim 1, further comprising forming an output for each portion of the data stream.

6. A method as claimed in claim 5, wherein for each damaged portion, if the rate of replacement associated with the damaged portion is greater than a threshold rate, the output is the damaged portion.

7. A method as claimed in claim 1, comprising selecting a damaged portion for replacement if the rate of replacement associated with the selected damaged portion is less than a threshold rate.

8. A method as claimed in claim 5, wherein for each damaged portion, if the rate of replacement associated with the damaged portion is less than a threshold rate, the method comprises:

selecting that damaged portion for replacement; and

replacing the selected damaged portion with a replacement portion, wherein the output for that damaged portion is the replacement portion.

9. A method as claimed in claim 5, wherein for each damaged portion, if the rate of replacement associated with the damaged portion is less than a threshold rate, the method further comprises applying a pre-defined algorithm to determine whether to replace the damaged portion and output a replacement portion or to output the damaged portion, the algorithm being dependent on at least one criterion.

10. A method as claimed in claim 5, wherein for each damaged portion, if the rate of replacement associated with the damaged portion is greater than a threshold rate, the method further comprises applying a pre-defined algorithm to determine whether to replace the damaged portion and output a replacement portion or to output the damaged portion, the algorithm being dependent on at least one criterion.

11. A method as claimed in claim 9, wherein a first criterion is the level of degradation of the damaged portion, wherein a level of degradation lower than a threshold level promotes output of the damaged portion.

12. A method as claimed in claim 11, further comprising determining the level of degradation of the damaged portion by performing a correlation between the damaged portion and a candidate replacement portion for the damaged portion.

13. A method as claimed in claim 9, wherein a second criterion is whether the damaged portion has a property characteristic of noise, wherein the damaged portion having a property characteristic of noise promotes output of the damaged portion.

14. A method as claimed in claim 13, further comprising determining whether the damaged portion has a property characteristic of noise by computing the zero crossing rate of the damaged portion.

15. A method as claimed in claim 9, wherein a third criterion is whether the damaged portion comprises a click, wherein the damaged portion comprising a click promotes selection of the damaged portion for replacement, replacement of the selected damaged portion with a replacement portion, and output of the replacement portion for the damaged portion.

16. A method as claimed in claim 15, further comprising determining if the damaged portion comprises a click by comparing the energy of the damaged portion to the energy of a portion proximal to the damaged portion.

17. A method as claimed in claim 5, further comprising:

analyzing the data stream to identify lost portions and error-free portions therein;

replacing each lost portion with a replacement portion, wherein the output for each lost portion is its respective replacement portion;

wherein the output for each error-free portion is that error-free portion.

18. A method as claimed in claim 1, further comprising:

analyzing segments of the data stream to identify those segments consisting of more than a first number of samples;

splitting each segment consisting of more than the first number of samples into portions, at least one of the portions consisting of up to the first number of samples.

19. A method of selectively replacing damaged portions of a data stream, the method comprising:

for each damaged portion, estimating an error rate of the data stream; and

applying a pre-defined algorithm to determine whether to replace the damaged portion, wherein the algorithm;

(a) causes the output of the damaged portion if the estimated error rate is above a threshold; and

(b) has a propensity to cause the output of a replacement portion in place of the damaged portion if the estimated error rate is below the threshold.

20. A method of selectively replacing damaged portions of a data stream, the method comprising:

for each damaged portion, estimating an error rate of the data stream; and

applying a pre-defined algorithm to determine whether to replace the damaged portion, wherein the algorithm;

(a) causes the output of a replacement portion in place of the damaged portion if the estimated error rate is below the threshold; and

b) has a propensity to cause the output of the damaged portion if the estimated error rate is above a threshold.

21. An apparatus configured to selectively replace damaged portions of a data stream, the apparatus comprising:

a damage indicator configured to analyze the data stream to identify damaged portions therein;

a selection module configured to select a damaged portion for replacement, wherein the selection module is configured to select the damaged portion for replacement in dependence on a rate of replacement, the rate of replacement being that at which previous portions of the data stream have been replaced; and

a replacement module configured to replace the selected damaged portion.