US 2009/0265167 A1 · SPEECH ENCODING APPARATUS AND SPEECH ENCODING METHOD

Abstract

Disclosed is an audio encoding device capable of adjusting a spectrum inclination of a quantized noise without changing the Formant weight. The device includes: an HPF (131) which extracts a high-frequency component of the frequency region from an input audio signal; a high-frequency energy level calculation unit (132) which calculates an energy level of the high-frequency component in a frame unit; an LPF (133) which extracts a low-frequency component of the frequency region from the input audio signal; a low-energy level calculation unit (134) which calculates an energy level of a low-frequency component in a frame unit; an inclination correction coefficient calculation unit (141) multiplies the difference between SNR of the high-frequency component and SNR of the low-frequency component inputted from an adder (140) by a constant and adds a bias component to the product so as to calculate an inclination correction coefficient ?3. The inclination correction coefficient is used for adjusting the spectrum inclination of a quantized noise.

Claims15

Dependent claims

A speech encoding apparatus comprising:

a linear prediction analyzing section that performs a linear prediction analysis with respect to a speech signal to generate a linear prediction coefficient;
a quantizing section that quantizes the linear prediction coefficient;
a perceptual weighting section that performs perceptual weighting filtering with respect to an input speech signal to generate a perceptual weighted speech signal using a transfer function including a tilt compensation coefficient for adjusting a spectral slope of a quantization noise;
a tilt compensation coefficient control section that controls the tilt compensation coefficient using a signal to noise ratio of the speech signal in a first frequency band;
and
an excitation search section that performs an excitation search of an adaptive codebook and fixed codebook to generate an excitation signal using the perceptual weighted speech signal.

3 more elements

Dependencies are inferred from the claim text.

Speech encoding apparatus and speech encoding method

Life of this patent

Speech encoding apparatus and speech encoding method

Life of this patent

Abstract

Claims15