METHOD AND APPARATUS FOR ENCODING AND DECODING AUDIO SIGNAL USING ADAPTIVE SINUSOIDAL CODING

• US 20110301961A1
• Filed: 02/16/2010
• Published: 12/08/2011
• Est. Priority Date: 02/16/2009
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Lee, Mi-Suk, Bae, Hyun-Joo, Lee, Byung-Sun
• Granted Patent: US 8,805,694 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/0204 using subband decomposition
• 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

A method and an apparatus for encoding and decoding audio signals using adaptive sinusoidal coding are provided. The audio signal encoding method includes the steps of dividing a synthesized audio signal into a plurality of sub-bands, calculating the energy of each sub-band, selecting a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands, and performing sinusoidal coding with regard to the selected sub-bands. Application of sinusoidal coding based on consideration of the amount of energy of each sub-band of the synthesized signal improves the quality of the synthesized signal more efficiently.

Claims

1. A method for encoding an audio signal, comprising:

receiving a transformed audio signal;

dividing the transformed audio signal into a plurality of sub-bands;

calculating energy of each of the sub-bands;

selecting a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands; and

performing sinusoidal coding with regard to the selected sub-bands.

2. The method of claim 1, wherein the predetermined number is determined by the number of pulses to be coded in one sub-band and the number of bits necessary to code one pulse.

3. The method of claim 1, wherein said performing sinusoidal coding with regard to the selected sub-bands comprises:

confirming if there are adjacent sub-bands among the selected sub-bands;

merging the adjacent sub-bands into one sub-band; and

performing sinusoidal coding with regard to the merged sub-band.

4. The method of claim 1, wherein in said performing sinusoidal coding with regard to the selected sub-bands,

sinusoidal coding is performed with regard to the selected sub-bands in the order of the amount of energy.

5. An apparatus for encoding an audio signal, comprising:

an input unit configured to receive a transformed audio signal;

a calculation unit configured to divide the transformed audio signal into a plurality of sub-bands, calculate energy of each of the sub-bands, and select a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands; and

a coding unit configured to perform sinusoidal coding with regard to the selected sub-bands.

6. The apparatus of claim 5, wherein the calculation unit is configured to determine the predetermined number based on the number of pulses to be coded in one sub-band and the number of bits necessary to code one pulse.

7. The apparatus of claim 5, wherein the calculation unit is configured to confirm if there are adjacent sub-bands among the selected sub-bands and merge the adjacent sub-bands into one sub-band, and

the coding unit is configured to perform sinusoidal coding with regard to the merged sub-band.

8. The apparatus of claim 5, wherein the coding unit is configured to perform sinusoidal coding with regard to the selected sub-bands in the order of the amount of energy.

9. A method for decoding an audio signal, comprising:

receiving a synthesized audio signal;

dividing the synthesized audio signal into a plurality of sub-bands;

calculating energy of each of the sub-bands;

selecting a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands; and

performing sinusoidal pulse sinusoidal decoding with regard to the selected sub-bands.

10. The method of claim 9, wherein the predetermined number is determined by the number of pulses to be coded in one sub-band and the number of bits necessary to code one pulse.

11. The method of claim 9, wherein in said performing sinusoidal decoding with regard to the selected sub-bands,

sinusoidal decoding is performed with regard to the selected sub-bands in the order of the amount of energy.

12. An apparatus for decoding an audio signal, comprising:

an input unit configured to receive a synthesized audio signal;

a calculation unit configured to divide the synthesized audio signal into a plurality of sub-bands, calculate energy of each of the sub-bands, and select a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands; and

a decoding unit configured to perform sinusoidal decoding with regard to the selected sub-bands.

13. The apparatus of claim 12, wherein the calculation unit is configured to determine the predetermined number based on the number of pulses to be coded in one sub-band and the number of bits necessary to code one pulse.

14. The apparatus of claim 12, wherein the decoding unit is configured to perform sinusoidal decoding, with regard to the selected sub-bands in the order of the amount of energy.

15. A method for encoding an audio signal, comprising:

receiving an audio signal;

performing Modified Discrete Cosine Transform (MDCT) with regard to the audio signal to output a MDCT coefficient;

synthesizing a high-frequency audio signal using the MDCT coefficient; and

performing sinusoidal coding with regard to the high-frequency audio signal.

16. The method of claim 15, wherein said performing sinusoidal coding with regard to the high-frequency audio signal comprises:

dividing the high-frequency audio signal into a plurality of sub-bands;

calculating energy of each of the sub-bands;

selecting a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands; and

performing sinusoidal coding with regard to the selected sub-bands.

17. An apparatus for encoding an audio signal, comprising:

an input unit configured to receive an audio signal;

a MDCT unit configured to perform MDCT with regard to the audio signal to output a MDCT coefficient;

a synthesis unit configured to synthesize a high-frequency audio signal using the MDCT coefficient; and

a sinusoidal coding unit configured to perform sinusoidal coding with regard to the high-frequency audio signal.

18. The apparatus of claim 17, wherein the sinusoidal coding unit is configured to divide the high-frequency signal into a plurality of sub-bands, calculate energy of each of the sub-bands, select a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands, and perform sinusoidal coding with regard to the selected sub-bands.

19. A method for decoding an audio signal, comprising:

receiving an audio signal;

performing MDCT with regard to the audio signal to output a MDCT coefficient;

synthesizing a high-frequency audio signal using the MDCT coefficient; and

performing sinusoidal decoding with regard to the high-frequency audio signal.

20. The method of claim 19, wherein said performing sinusoidal decoding with regard to the high-frequency audio signal comprises:

dividing the high-frequency signal into a plurality of sub-bands;

calculating energy of each of the sub-bands;

selecting a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands; and

performing sinusoidal decoding with regard to the selected sub-bands.

21. An apparatus for decoding an audio signal, comprising:

an input unit configured to receive an audio signal;

a MDCT unit configured to perform MDCT with regard to the audio signal to output a MDCT coefficient;

a synthesis unit configured to synthesize a high-frequency audio signal using the MDCT coefficient; and

a sinusoidal decoding unit configured to perform sinusoidal decoding with regard to the high-frequency audio signal.

22. The apparatus of claim 21, wherein the sinusoidal decoding unit is configured to divide the high-frequency signal into a plurality of sub-bands, calculate energy of each of the sub-bands, select a predetermined number of sub-bands having a relatively large amount of energy from the sub-bands, and perform sinusoidal decoding with regard to the selected sub-bands.