Frame Loss Recovering Method, And Audio Decoding Method And Device Using Same

• US 20150255074A1
• Filed: 09/11/2013
• Published: 09/10/2015
• Est. Priority Date: 09/13/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Jeong, Gyuhyeok, Jeon, Hyejeong, Kang, Ingyu
• Granted Patent: US 9,633,662 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G10L 19/005 Correction of errors induced by the transmission channel, if related to the coding algorithm
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/12 the excitation function being a code excitation, e.g. in code excited linear prediction [CELP] vocoders

Abstract

The present invention relates to a frame loss recovering method, an audio decoding method, and an apparatus using the method. A method of recovering a frame loss of an audio signal according to the present invention includes: grouping transform coefficients of at least one frame into a predetermined number of bands among previous frames of a current frame; deriving an attenuation constant according to a tonality of the bands; and recovering transform coefficients of the current frame by applying the attenuation constant to the previous frame of the current frame.

Claims

1. A method of recovering a frame loss, the method comprising:

grouping transform coefficients of at least one frame into a predetermined number of bands among previous frames of a current frame;

deriving an attenuation constant according to a tonality of the bands; and

recovering transform coefficients of the current frame by applying the attenuation constant to the previous frame of the current frame.

2. The method of claim 1, wherein the attenuation constant is derived on the basis of transform coefficients of previous N normal frames (where N is an integer) of the current frame.

3. The method of claim 2, wherein the N is the number of buffers for storing information of the previous frame.

4. The method of claim 1, wherein in a band having a strong tonality of the transform coefficient, the attenuation constant is derived on the basis of a correlation between transform coefficients of previous normal frames.

5. The method of claim 4, wherein a per-band correlation is used as a per-band attenuation constant, and a band having a high positional correlation of an inter-frame sinusoidal pulse has a high correlation.

6. The method of claim 1, wherein in a band having a weak tonality of the transform coefficient, the attenuation constant is derived on the basis of energies for previous normal frames.

7. The method of claim 6, wherein the attenuation constant is a ratio between an energy value for a previous frame of the current frame and an energy prediction value predicted for the current frame on the basis of a change between energies of previous frames.

8. The method of claim 1, wherein the transform coefficient of the current frame is recovered to a value obtained by multiplying an attenuation constant derived for each band by a per-band transform coefficient of the previous frame.

9. The method of claim 8, wherein if the previous frame of the current frame is a recovered frame, the transform coefficient of the current frame is recovered by additionally applying the attenuation constant of the current frame to the attenuation constant of the previous frame.

10. An audio decoding method comprising:

determining whether there is a loss in a current frame;

if the current frame has lost, recovering a transform coefficient of the current frame on the basis of transform coefficients of previous frames of the current frame; and

inverse-transforming the recovered transform coefficient,

wherein in the recovering of the transform coefficient, the transform coefficient of the current frame is recovered on the basis of a per-band tonality of transform coefficients of at least one frame among the previous frames.

11. The method of claim 10, wherein the recovering of the transform coefficient comprises:

grouping transform coefficients of at least one frame into a predetermined number of bands among previous frames of the current frame;

deriving an attenuation constant according to a tonality of the bands; and

recovering transform coefficients of the current frame by applying the attenuation constant to the previous frame of the current frame.

12. The audio decoding method of claim 11, wherein the attenuation constant is derived on the basis of transform coefficients of a specific number of previous normal frames of the current frame.

13. The audio decoding method of claim 11, wherein in a band having a strong tonality of the transform coefficient, the attenuation constant is derived on the basis of a correlation between transform coefficients of previous normal frames.

14. The audio decoding method of claim 11, wherein in a band having a weak tonality of the transform coefficient, the attenuation constant is derived on the basis of energies for previous normal frames.

15. The audio decoding method of claim 10, wherein the transform coefficient of the current frame is recovered to a value obtained by multiplying an attenuation constant derived for each band by a per-band transform coefficient of the previous frame.

16. The audio decoding method of claim 15, wherein if the previous frame of the current frame is a recovered frame, the transform coefficient of the current frame is recovered by additionally applying the attenuation constant of the current frame to the attenuation constant of the previous frame.

17. The audio decoding method of claim 16, wherein the attenuation constant additionally applied to a band having a strong tonality is less than or equal to an attenuation constant additionally applied to a band having a weak tonal component.