Apparatus and method determining weighting function for linear prediction coding coefficients quantization

• US 20110295600A1
• Filed: 05/26/2011
• Published: 12/01/2011
• Est. Priority Date: 05/27/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: Oh, Eun Mi, Sung, Ho Sang
• Granted Patent: US 9,236,059 B2
• Time in Patent Office: Days
• US Class Current: 704/219
• CPC Class Codes: G10L 19/032 Quantisation or dequantisation of spectral components
• 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

Abstract

An apparatus determining a weighting function for line prediction coding coefficients quantization converts a linear prediction coding (LPC) coefficient of an input signal into one of a line spectral frequency (LSF) coefficient and an immitance spectral frequency (ISF) coefficient and determines a weighting function associated with one of an importance of the ISF coefficient and importance of the LSF coefficient using one of the converted ISF coefficient and the converted LSF coefficient.

Claims

1. An apparatus determining a weighting function, comprising:

a coefficient conversion unit to convert a linear prediction coding (LPC) coefficient of an input signal into one of a line spectral frequency (LSF) coefficient and an immitance spectral frequency (ISF) coefficient;

a weighting function determination unit to determine a weighting function associated with one of importance of the ISF coefficient and importance of the LSF coefficient; and

a quantization unit to quantize one of the converted ISF coefficient and the converted LSF coefficient using the determined weighting function, and to convert one of the quantized ISF coefficient and the quantized LSF coefficient into a quantized LPC coefficient.

2. The apparatus of claim 1, wherein the weighting function determination unit determines using a spectral magnitude of the input signal a weighting function of each magnitude associated with a spectral envelope of the input signal.

3. The apparatus of claim 2, wherein the weighting function determination unit determines the weighting function of each magnitude using a magnitude of a spectral bin corresponding to one of a frequency of the ISF coefficient and a frequency of the LSF coefficient.

4. The apparatus of claim 2, wherein the weighting function determination unit determines the weighting function of each magnitude using a magnitude of a spectral bin corresponding to one of a frequency of the ISF coefficient and a frequency of the LSF coefficient and a magnitude of at least one neighboring spectral bin disposed around the spectral bin.

5. The apparatus of claim 2, wherein the weighting function determination unit determines a weighting function of each frequency using one of frequency information about the ISF coefficient and frequency information about the LSF coefficient and combines the weighting function of each frequency with the weighting function of each magnitude.

6. The apparatus of claim 5, wherein the weighting function determination unit determines the weighting function of each frequency using perceptual characteristics and a formant distribution of the input signal.

7. The apparatus of claim 6, wherein the weighting function determination unit extracts the perceptual characteristics of the input signal based on a bark scale.

8. The apparatus of claim 6, wherein the weighting function determination unit determines the weighting function of each frequency based on a first formant of the formant distribution.

9. The apparatus of claim 1, wherein the weighting function determination unit determines the weighting function based on a frequency band of the input signal.

10. The apparatus of claim 1, wherein the weighting function determination unit determines the weighting function based on an encoding mode of the input signal.

11. The apparatus of claim 1, wherein the weighting function determination unit determines the weighting function using tilt information about a spectral magnitude based on spectrum analysis of the input signal.

12. A method of determining a weighting function, comprising:

converting, using at least one processor, a linear prediction coding (LPC) coefficient of an input signal into one of a line spectral frequency (LSF) coefficient and an immitance spectral frequency (ISF) coefficient;

determining, by the at least one processor, a weighting function associated with an importance of the LPC coefficient using one of the converted ISF coefficient and the converted LSF coefficient;

quantizing, by the at least one processor, using the determined weighting function one of the converted ISF coefficient and the converted LSF coefficient; and

converting, by the at least one processor, into a quantized LPC coefficient one of the quantized ISF coefficient and the quantized LSF coefficient.

13. The method of claim 12, wherein the determining of the weighting function determines using a spectral magnitude of the input signal a weighting function of each magnitude associated with a spectral envelope of the input signal.

14. The method of claim 13, wherein the determining of the weighting function determines the weighting function of each magnitude using a magnitude of a spectral bin corresponding to one of a frequency of the ISF coefficient and a frequency of the LSF coefficient.

15. The method of claim 13, wherein the determining of the weighting function determines the weighting function of each magnitude using a magnitude of a spectral bin corresponding to one of a frequency of the ISF coefficient and a frequency of the LSF coefficient and a magnitude of at least one neighboring spectral bin disposed around the spectral bin.

16. The method of claim 13, wherein the determining of the weighting function comprises determining a weighting function of each frequency using one of frequency information about the ISF coefficient and frequency information about the LSF coefficient and combining the weighting function of each frequency with the weighting function of each magnitude.

17. The method of claim 16, wherein the determining of the weighting function of each frequency determines the weighting function of each frequency using perceptual characteristics and a formant distribution of the input signal.

18. The method of claim 17, wherein the determining of the weighting function of each frequency extracts the perceptual characteristics of the input signal based on a bark scale.

19. The method of claim 17, wherein the determining of the weighting function of each frequency determines the weighting function of each frequency based on a first formant of the formant distribution.

20. The method of claim 12, wherein the determining of the weighting function determines the weighting function based on a frequency band of the input signal.

21. The method of claim 12, wherein the determining of the weighting function determines the weighting function based on an encoding mode of the input signal.

22. The method of claim 12, wherein the determining of the weighting function determines the weighting function using tilt information about a spectral magnitude based on spectrum analysis of the input signal.

23. At least one non-transitory computer-readable medium comprising computer readable instructions that control at least one processor to perform the method of claim 12.

24. A method, comprising:

converting, by at least one processor, a linear prediction coding (LPC) coefficient of speech into one of a line spectral frequency coefficient (LSF) and an immitance spectral frequency coefficient (ISF);

determining a weighted importance of the LPC coefficient by selecting and quantizing one of the LSF and ISF coefficients, where the weighted importance is based upon a frequency band of the speech, an encoding mode of the speech and spectrum analysis of the speech; and

converting the quantized selection into a quantized LPC coefficient.

25. At least non-transitory one computer readable medium comprising computer readable instructions that control at least one processor to implement the method of claim 24.