US 2010/0250244 A1 · ENCODER AND DECODER

Abstract

There is provided an encoder capable of improving inter-channel prediction (ICP) performance in scalable stereo sound encoding using an ICP. In the encoder, ICP analysis units (113, 114, 115) use, as reference signal candidates, a frequency coefficient (sL′(f)) in the low-band portion of a side residual signal, a frequency coefficient (mM,i(f)) in each sub-band portion of a monaural residual signal, and a frequency coefficient (mL(f)) in the low-band portion of the monaural residual signal, respectively, and perform an ICP analysis between the respective these candidates and a frequency coefficient (sM,i(f)) in each sub-band portion of the side residual signal to generate first, second, and third ICP coefficients. A selection unit (116) selects an optimum reference signal from among the reference signal candidates by checking the relationship between the respective reference signal candidates and the frequency coefficient (sM,i(f)) in each sub-band portion of the side residual signal and outputs, to an ICP parameter quantization unit (117), a reference signal ID indicating the selected reference signal and an ICP coefficient corresponding to the reference signal.

Claims11

Dependent claims

1-10. (canceled)

A coding apparatus comprising:

a monaural signal generation section that synthesizes a first channel signal and a second channel signal in a stereo signal, to generate a monaural signal, and generates a side signal, the side signal being a difference between the first channel signal and the second channel signal;
a side residual signal acquiring section that acquires a side residual signal, the side residual signal being a linear prediction residual signal for the side signal;
a monaural residual signal acquiring section that acquires a monaural residual signal, the monaural residual signal being a linear prediction residual signal for the monaural signal;
a first spectrum division section that divides the side residual signal into a low band part being a lower band than a predetermined frequency and a middle band part being a higher band than the predetermined frequency;
a second spectrum division section that divides the monaural residual signal into a low band part being a lower band than a predetermined frequency and a middle band part being a higher band than the predetermined frequency;
a selection section that selects an optimal signal as a reference signal from reference signal candidates by checking relationships between each reference signal candidate and a target signal, the reference signal candidates being frequency coefficients for the low band part of the side residual signal, frequency coefficients for the middle band part of the monaural residual signal, and frequency coefficients for the low band part of the monaural residual signal, and the target signal being frequency coefficients for the middle band part of the side residual signal;
and
an inter channel prediction analysis section that performs an inter-channel prediction analysis between the reference signal and the target signal, to acquire inter-channel prediction coefficients.

5 more elements

A decoding apparatus comprising:

an inter-channel prediction parameter decoding section that decodes a reference signal identification identifying a reference signal and decodes inter-channel prediction coefficients acquired by performing an inter-channel prediction analysis between the reference signal and frequency coefficients for a middle band part being a higher band than a predetermined frequency of a side residual signal, the reference signal being selected from:
frequency coefficients for a low band part being a lower band than the predetermined frequency of the side residual signal, the side residual signal being a linear prediction residual signal for a side signal being a difference between a first channel signal and a second channel signal in a stereo signal;
frequency coefficients for a middle band part being a higher band than the predetermined frequency of a monaural residual signal, the monaural residual signal being the linear prediction residual signal for a monaural signal generated by synthesizing the first channel signal and the second channel signal;
and frequency coefficients for the low band part lower band than the predetermined frequency of the monaural residual signal;
an inter-channel prediction synthesis section that calculates the frequency coefficients for the middle band part of the side residual signal by filtering the reference signal using the inter-channel prediction coefficients as filter coefficients;
an addition section that adds the frequency coefficients for the low band part of the side residual signal and the frequency coefficients for the middle band part of the side residual signal, to acquire frequency coefficients for an entire band of the side residual signal;
a transformation section that transforms frequency coefficients for the entire band of the side residual signal into a time-domain side residual signal;
a linear prediction synthesis section that performs linear prediction synthesis filtering for the time-domain side residual signal, to acquire the side signal;
and
a stereo signal calculation section that acquires the first channel signal and the second channel signal using the monaural signal and the side signal.

7 more elements

A decoding method comprising the steps of:

an inter-channel prediction parameter decoding step of decoding a reference signal identification identifying a reference signal and decoding inter-channel prediction coefficients acquired by performing an inter-channel prediction analysis between the reference signal and frequency coefficients for a middle band part being a higher band than a predetermined frequency of a side residual signal, the reference signal being selected from:
frequency coefficients for a low band part being a lower band than the predetermined frequency of the side residual signal, the side residual signal being a linear prediction residual signal for a side signal being a difference between a first channel signal and a second channel signal in a stereo signal;
frequency coefficients for a middle band part being a higher band than the predetermined frequency of a monaural residual signal, the monaural residual signal being the linear prediction residual signal for a monaural signal generated by synthesizing the first channel signal and the second channel signal;
and frequency coefficients for the low band part lower band than the predetermined frequency of the monaural residual signal;
an inter-channel prediction synthesis step of calculating the frequency coefficients for the middle band part of the side residual signal by filtering the reference signal using the inter-channel prediction coefficients as filter coefficients;
an addition step of adding the frequency coefficients for the low band part of the side residual signal and the frequency coefficients for the middle band part of the side residual signal, to acquire frequency coefficients for an entire band of the side residual signal;
a transformation step of transforming frequency coefficients for the entire band of the side residual signal into a time-domain side residual signal;
a linear prediction synthesis step of performing linear prediction synthesis filtering for the time-domain side residual signal, to acquire the side signal;
and
a stereo signal calculation step of acquiring the first channel signal and the second channel signal using the monaural signal and the side signal.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application

12/740,020Filed 31 Oct 2008

Priority

JP 2007-28462231 Oct 2007

Published

30 Sep 2010

Term ends

Not estimatedThe source records don’t support an estimate.

Classification5 codes

G10L 19/24
Vocoders using multiple modes: variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical…
G10L 19/008
Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals,…:…
G10L 19/0204
Using spectral analysis, e.g. transform vocoders or subband vocoders: using subband decomposition
G10L 19/04
Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals,…:…

Encoder and decoder

Life of this patent

Encoder and decoder

Life of this patent

Abstract

Claims11