Method and apparatus for encoding and decoding high frequency signal

• US 8,825,476 B2
• Filed: 04/08/2013
• Issued: 09/02/2014
• Est. Priority Date: 11/17/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choo, Ki-hyun, Oh, Eun-mi, Miao, Lei
• Primary Examiner(s): Chawan, Vijay B
• Application Number:
  US13/858,688
• Publication Number:
  US 20130226566A1
• Time in Patent Office: 512 Days
• Field of Search: 704/219, 704/265, 704/222, 704/216, 704/208, 704/207, 704/212, 704/230, 704/262, 704/225, 375/240.15, 455/228
• US Class Current: 704/222
• CPC Class Codes: G10L 19/02 using spectral analysis, e.g. transform vocoders or subband vocoders
• CPC Class Codes: G10L 19/0208 Subband vocoders
• CPC Class Codes: G10L 19/04 using predictive techniques
• CPC Class Codes: G10L 19/06 Determination or coding of the spectral characteristics, e.g. of the short-term prediction coefficients
• CPC Class Codes: G10L 19/07 Line spectrum pair [LSP] vocoders
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: G10L 21/038 using band spreading techniques
• CPC Class Codes: G10L 25/12 the extracted parameters being prediction coefficients
• CPC Class Codes: G10L 25/21 the extracted parameters being power information
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

Provided are a method and apparatus for encoding and decoding a high frequency signal by using a low frequency signal. The high frequency signal can be encoded by extracting a coefficient by linear predicting a high frequency signal, and encoding the coefficient, generating a signal by using the extracted coefficient and a low frequency signal, and encoding the high frequency signal by calculating a ratio between the high frequency signal and an energy value of the generated signal. Also, the high frequency signal can be decoded by decoding a coefficient, which is extracted by linear predicting a high frequency signal, and a low frequency signal, and generating a signal by using the decoded coefficient and the decoded low frequency signal, and adjusting the generated signal by decoding a ratio between the generated signal and an energy value of the high frequency signal.

Claims

1. A method of decoding a high frequency signal, the method comprising:

decoding a coefficient extracted by linear predicting a high frequency signal, and a low frequency signal, and generating a signal based on the decoded coefficient and the decoded low frequency signal;

decoding a gain between an energy value of the generated signal and an energy value of the high frequency signal; and

adjusting the generated signal using the decoded gain and the decoded coefficient.

2. The method of claim 1, wherein the generating of a signal comprises:

generating a first signal by decoding the extracted coefficient;

generating a second signal in a high frequency band by using the decoded low frequency signal; and

generating a third signal by calculating the first and second signals by using a preset method.

3. The method of claim 1, wherein the generating of a signal comprises:

generating a first signal by decoding the extracted coefficient;

extracting a residual signal by linear predicting the decoded low frequency signal;

generating a second signal in a high frequency band by using the extracted residual signal; and

generating a third signal by calculating the first and second signals by using a preset method.

4. The method of claim 2, wherein the generating of a first signal comprises:

generating a fourth signal by using the decoded coefficient; and

generating the first signal by normalizing the fourth signal.

5. The method of claim 2, wherein the generating of a second signal and the generating of a third signal are performed in the frequency domain.

6. The method of claim 3, wherein the generating of a first signal comprises:

generating a fourth signal by using the decoded coefficient; and

generating the first signal by normalizing the fourth signal.

7. The method of claim 3, wherein the generating of a second signal and the generating of a third signal are performed in the frequency domain.

8. The method of claim 1, wherein the generating of a signal comprises:

generating the signal by decoding the extracted coefficient, and then generating a first signal by performing a first point-transform to the frequency domain;

performing the first point-transform on the decoded low frequency signal to the frequency domain, and generating a second signal in the high frequency band by using the transformed low frequency signal; and

generating the signal by calculating the first and second signals by using the preset method, and then generating a third signal by performing a first point-inverse transform to a time domain, and

the decoding a coefficient comprises;

performing a second point-transform on the third signal to the frequency domain;

decoding the ratio between the generated signal and the energy value of the high frequency signal; and

adjusting the transformed third signal according to each preset unit by using the decoded ratio.

9. The method of claim 8, wherein the generating of a first signal comprises:

generating a fourth signal by using the decoded coefficient;

normalizing the fourth signal; and

generating the first signal by performing the first point-transform on the normalized fourth signal to the frequency domain.

10. The method of claim 1, wherein the generating of a signal comprises:

decoding the extracted coefficient and the low frequency signal;

extracting a residual signal by linear predicting the decoded low frequency signal; and

synthesizing the extracted residual signal and the extracted coefficient.

11. The method of claim 10, wherein the adjusting of the generated signal is performed in the frequency domain.

12. The method of claim 1, further comprising adjusting the decoded ratio so that the signal does not remarkably change in the boundary of the decoded low frequency signal and the high frequency signal that is to be decoded.

13. The method of claim 1, further comprising adjusting the adjusted signal so that an energy value between the preset units does not remarkably change.

14. The method of claim 1, wherein the generating of a signal comprises:

generating a first signal by decoding the extracted coefficient;

extracting a residual signal by decoding and linear predicting the low frequency signal; and

generating a second signal by calculating the first signal and the extracted residual signal by using a preset method.

15. A method of decoding a high frequency signal, the method comprising:

generating a first signal by decoding a coefficient extracted by linear predicting a high frequency signal;

extracting a residual signal by decoding and linear predicting a low frequency signal;

generating a second signal based on the generated first signal and the extracted residual signal;

decoding a gain calculated by using the high frequency signal and the low frequency signal, and adjusting the decoded gain using the decoded coefficient; and

adjusting the generated second signal by applying the adjusted gain to the second signal.

16. An apparatus for decoding a high frequency signal, the apparatus comprising:

a low frequency signal decoding unit to decode a low frequency signal and an energy value of the high frequency signal;

an excitation signal generating unit to generate an excitation signal of the high frequency signal by using the decoded low frequency signal; and

a high frequency signal generating unit to generate a decoded high frequency signal by adjusting an energy value of the generated excitation signal based on the decoded energy value of the high frequency signal.