Method and apparatus for encoding and decoding high frequency signal

• US 8,417,516 B2
• Filed: 01/20/2012
• Issued: 04/09/2013
• 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, Miao, Lei, Oh, Eun-mi
• Primary Examiner(s): Chawan, Vijay B
• Application Number:
  US13/354,749
• Publication Number:
  US 20120116757A1
• Time in Patent Office: 445 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: 704/219
• 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 encoding a high frequency signal, the method comprising:

extracting a coefficient by linear predicting a high frequency signal, and encoding the extracted coefficient;

generating a signal based on the extracted coefficient and a low frequency signal;

calculating a gain according to a ratio between an energy value of the high frequency signal and an energy value of the generated signal; and

encoding the high frequency signal based on the calculated gain and the extracted coefficient.

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

generating a first signal by using the extracted coefficient;

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

generating a third signal by calculating the first and second signals in a predetermined method.

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

generating a fourth signal by using the extracted coefficient; and

generating the first signal by normalizing the fourth signal.

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

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

generating a first signal by using the extracted coefficient;

extracting a residual signal by linear predicting the 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.

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

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

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

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

the encoding of the high frequency signal comprises;

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

encoding the high frequency signal by calculating a ratio between an energy value of the transformed high frequency signal and an energy value of the transformed third signal according to each preset unit.

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

generating a fourth signal by using the extracted coefficient;

normalizing the generated fourth signal; and

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

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

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

synthesizing the extracted residual signal and the extracted coefficient; and

generating the signal by calculating the synthesized residual signal and the high frequency signal by using a preset method.

9. The method of claim 8, wherein the generating is performed in the frequency domain.

10. The method of claim 1, further comprising adjusting each of the calculated ratios by using a ratio of tonality of the low frequency signal to tonality of the high frequency signal.

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

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

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

generating 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.