ENCODER, DECODER, AND THE METHODS THEREFOR

• US 20110046946A1
• Filed: 05/29/2009
• Published: 02/24/2011
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: III Holdings 12, LLC (Intellectual Ventures LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Liu, Zongxian, Chong, Kok Seng
• Granted Patent: US 8,452,587 B2
• Time in Patent Office: Days
• US Class Current: 704/203
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding

Abstract

Provided is an encoder which can decode a high-quality stereo signal while keeping the amount of information in the bit allocation information to a minimum when a scalable coding technique is used for a stereo signal. In the encoder, a principal component analysis (PCA) converter (101) PCA converts the left signal and the right signal of the stereo signal and generates the main signal of the first layer and the sub-signal of the first layer. In the first layer to the M-th layer (where M is a natural number, 2 or greater), an adaptive residual encoder (102-m) (where m is a natural number from 1 to M) compares the importance of the main signal of the m-th layer and the importance of the sub-signal of the m-th layer, selects the signal having the higher importance, encodes the selected signal, and generates the encoded data of the m-th layer. From the first layer to the M−1-st layer, the adaptive residual encoder (102-m) generates the signal obtained by subtracting the decoded signal of the encoded data of the m-th layer from the selected signal as the main signal of the m+1-st layer, and generates the unselected signal as the sub-signal of the m+1-st layer.

Claims

1. An encoding apparatus comprising:

a transformation section that performs principal component analysis transformation of a first channel signal and a second channel signal of an input stereo signal, to generate a first layer primary signal and a first layer secondary signal;

an m-th layer selecting section that compares importance of an m-th layer primary signal (where m is a natural number equal to or greater than 1 and equal to or less than M) and importance of an m-th layer secondary signal in a first layer to an M-th layer (where M is a natural number equal to or greater than

     2), and selects a signal of higher importance;

an m-th layer encoding section that encodes the signal selected in the m-th layer selecting section, to generate m-th layer encoded data in the first layer to the M-th layer;

an m-th layer decoding section that decodes the m-th encoded data to generate an m-th layer decoded signal in the first layer to an (M−

1)-th layer;

a subtracting section that generates a signal obtained by subtracting the m-th layer decoded signal from the signal selected in the m-th layer selecting section, and a signal that is not selected in the m-th layer selecting section, as an (m+1)-th layer primary signal and an (m+1)-th layer secondary signal, in the first layer to the (M−

1)-th layer; and

a transmitting section that transmits encoded data of the first layer to the M-th layer and signal information indicating signals selected in selecting sections in the first layer to the M-th layer.

2. The encoding apparatus according to claim 1, wherein:

the selecting section always selects the primary signal in the first layer; and

the transmitting section transmits the signal information of a second layer to the M-th layer.

3. The encoding apparatus according to claim 1, wherein:

the selecting section always selects the primary signal in the first layer to an (i−

1)-th layer (where i is a natural number equal to or greater than 2 and equal to or less than M); and

the transmitting section transmits the signal information of an i-th layer to the M-th layer.

4. The encoding apparatus according to claim 1, wherein the importance comprises an indicator represented by signal energy.

5. The encoding apparatus according to claim 1, wherein the importance comprises an indicator represented by a signal to noise ratio.

6. The encoding apparatus according to claim 1, wherein the importance comprises an indicator represented by a mask to noise ratio.

7. A decoding apparatus comprising:

a receiving section that receives encoded data of a first layer to an M-th layer and signal information indicating a signal encoded in each of the first layer to the M-th layer, the encoded data being obtained by encoding a primary signal and a secondary signal in the first layer to the M-th layer (where M is a natural number equal to or greater than

     2), and the primary signal and the secondary signal being obtained by performing principal component analysis transformation of a first channel signal and a second channel signal of an input stereo signal;

a decoding section that decodes the encoded data of an m-th layer based on the signal information of the m-th layer in the m-th layer (where m is a natural number between 1 and M), and obtains an m-th layer decoded signal;

an adding section that adds decoded signals of the first layer to the M-th layer to generate the primary signal and the secondary signal; and

an inverse transformation section that performs inverse transformation of the principal component analysis transformation using the primary signal and the secondary signal, and obtains the first channel signal and the second channel signal.

8. An encoding method comprising:

a transforming step of performing principal component analysis transformation of a first channel signal and a second channel signal of an input stereo signal, to generate a first layer primary signal and a first layer secondary signal;

an m-th layer selecting step of comparing importance of an m-th layer primary signal (where m is a natural number equal to or greater than 1 and equal to or less than M) and importance of an m-th layer secondary signal in a first layer to an M-th layer (where M is a natural number equal to or greater than

     2), and selecting a signal of higher importance;

an m-th layer encoding step of encoding the signal selected in the m-th layer selecting step, to generate m-th layer encoded data in the first layer to the M-th layer;

an m-th layer decoding step of decoding the m-th encoded data to generate an m-th layer decoded signal in the first layer to an (M−

1)-th layer;

a subtracting step of generating a signal obtained by subtracting the m-th layer decoded signal from the signal selected in the m-th layer selecting step, and a signal that is not selected in the m-th layer selecting step, as an (m+1)-th layer primary signal and an (m+1)-th layer secondary signal, in the first layer to the (M−

1)-th layer; and

a transmitting step of transmitting encoded data of the first layer to the M-th layer and signal information indicating signals selected in selecting steps in the first layer to the M-th layer.

9. A decoding method comprising:

a receiving step of receiving encoded data of a first layer to an M-th layer and signal information indicating a signal encoded in each of the first layer to the M-th layer, the encoded data being obtained by encoding a primary signal and a secondary signal in the first layer to the M-th layer (where M is a natural number equal to or greater than

     2), and the primary signal and the secondary signal being obtained by performing principal component analysis transformation of a first channel signal and a second channel signal of an input stereo signal;

a decoding step of decoding the encoded data of an m-th layer based on the signal information of the m-th layer in the m-th layer (where m is a natural number between 1 and M), and obtaining an m-th layer decoded signal;

an adding step of adding decoded signals of the first layer to the M-th layer to generate the primary signal and the secondary signal; and

an inverse transforming step of performing inverse transformation of the principal component analysis transformation using the primary signal and the secondary signal, and obtaining the first channel signal and the second channel signal.