Method and apparatus for adaptive sub-band allocation of spectral coefficients
AssigneeElectronics and Telecommunications Research Institute
InventorsHyun Woo KIM, Hyun Joo BAE, Byung Sun LEE
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Abstract
An apparatus and method for adaptive sub-band allocation of spectral coefficients are disclosed. The sizes of sub-bands are determined according to the distribution of spectral coefficients transformed from an input speech/audio signal to perform more elaborate quantization in units of sub-bands. Thus, quantization noise of the spectral coefficients is reduced, and sound quality in a frequency region is enhanced, thereby improving the quality of the signal.
Claims14
A method for adaptive sub-band allocation of spectral coefficients, comprising the steps of:
- allocating spectral coefficients transformed from an audio signal to each band;
- determining whether to permit short sub-bands for the band or not;
- determining the type of sub-bands for each band corresponding to the distribution of the spectral coefficients upon permission of short sub-bands;
- and
- allocating the spectral coefficients for the band to the sub-bands according to the determined type and quantizing the spectral coefficients for each sub-band to output a bit stream.
An apparatus for adaptive sub-band allocation of spectral coefficients, comprising:
- a frequency transformation unit for transforming an audio signal into spectral coefficients of a frequency domain;
- a band setting unit for allocating the spectral coefficients for each band, calculating the spectral flatness and distribution of the spectral coefficients to set the type of sub-bands for each band and allocate the spectral coefficients;
- and
- a quantization unit for calculating the gain and shape of the spectral coefficients for each sub-band and quantizing the same.
Dependencies are inferred from the claim text.