METHOD AND APPARATUS FOR DECODING AUDIO SIGNAL

• US 20110178807A1
• Filed: 01/21/2011
• Published: 07/21/2011
• Est. Priority Date: 01/21/2010
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: BAE, Hyun-Joo, LEE, Byung-Sun, KIM, Hyun-Woo, LEE, Mi-Suk, YANG, Heesik, SUNG, Jongmo
• Granted Patent: US 9,111,535 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G10L 19/093 using sinusoidal excitation models
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding

Abstract

Provided are a method and an apparatus for decoding an audio signal. A method for decoding an audio signal encoded by a layered sinusoidal pulse coding scheme using one or more sinusoidal pulses includes decoding the encoded audio signal, setting a smoothing frequency band of the decoded audio signal according to a layer structure of the layered sinusoidal pulse coding scheme, dividing the smoothing frequency band into one or more subbands, and smoothing the decoded audio signal on a subband-by-subband basis. Accordingly, a decoding operation time can be reduced and the quality of a synthesized signal can be improved by variably setting a frequency band to be smoothed, when decoding an audio signal encoded by a layered sinusoidal pulse coding scheme using one or more sinusoidal pulses.

Claims

1. A method for decoding an audio signal encoded by a layered sinusoidal pulse coding scheme using one or more sinusoidal pulses, comprising:

decoding the encoded audio signal;

setting a smoothing frequency band of the decoded audio signal according to a layer structure of the layered sinusoidal pulse coding scheme;

dividing the smoothing frequency band into one or more subbands; and

smoothing the decoded audio signal on a subband-by-subband basis.

2. The method of claim 1, wherein said setting a smoothing frequency band of the decoded audio signal according to a layer structure of the layered sinusoidal pulse coding scheme comprises setting the smoothing frequency band variably according to the number of bits allocated on a subband-by-subband basis when encoding the audio signal by the layered sinusoidal pulse coding scheme.

3. The method of claim 1, wherein said setting a smoothing frequency band of the decoded audio signal according to a layer structure of the layered sinusoidal pulse coding scheme comprises setting the smoothing frequency band according to the static characteristics of the encoded audio signal.

4. The method of claim 1, wherein said smoothing the decoded audio signal on a subband-by-subband basis comprises smoothing the decoded audio signal with reference to a prestored audio signal of the previous frame of the decoded audio signal.

5. The method of claim 1, wherein said smoothing the decoded audio signal on a subband-by-subband basis comprises smoothing the position, gain factor and code of a sinusoidal pulse used to encode the audio signal.

6. An apparatus for decoding an audio signal encoded by a layered sinusoidal pulse coding scheme using one or more sinusoidal pulses, comprising:

a decoding unit configured to decode the encoded audio signal;

a smoothing frequency band setting unit configured to set a smoothing frequency band of the decoded audio signal according to a layer structure of the layered sinusoidal pulse coding scheme; and

a smoothing unit configured to divide the smoothing frequency band into one or more subbands and smooth the decoded audio signal on a subband-by-subband basis.

7. The apparatus of claim 6, wherein the smoothing frequency band setting unit sets the smoothing frequency band variably according to the number of bits allocated on a subband-by-subband basis when encoding the audio signal by the layered sinusoidal pulse coding scheme.

8. The apparatus of claim 6, wherein the smoothing frequency band setting unit sets the smoothing frequency band according to the static characteristics of the encoded audio signal.

9. The apparatus of claim 6, further comprising a delay buffer configured to store an audio signal of the previous frame of the decoded audio signal,

wherein the smoothing unit smooths the decoded audio signal with reference to an audio signal of the previous frame of the decoded audio signal prestored in the delay buffer.

10. The apparatus of claim 6, wherein the smoothing unit smooths the position, gain factor and code of a sinusoidal pulse used to encode the audio signal.

11. An audio signal decoding method comprising:

receiving an encoded audio signal;

decoding the encoded audio signal;

setting a smoothing frequency band of the decoded audio signal according to the number of bits allocated to the encoded audio signal; and

smoothing the decoded audio signal with respect to the smoothing frequency band.

12. The audio signal decoding method of claim 11, wherein said smoothing the decoded audio signal with respect to the smoothing frequency band comprises:

dividing the smoothing frequency band into one or more subbands; and

smoothing the decoded audio signal on a subband-by-subband basis.

13. The audio signal decoding method of claim 11, wherein said smoothing the decoded audio signal with respect to the smoothing frequency band comprises smoothing the decoded audio signal with reference to a prestored audio signal of the previous frame of the decoded audio signal.