Encoder, decoder, and the methods therefor

• US 8,452,587 B2
• Filed: 05/29/2009
• Issued: 05/28/2013
• 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
• Primary Examiner(s): He, Jialong
• Assistant Examiner(s): Shan, Jie
• Application Number:
  US12/990,706
• Publication Number:
  US 20110046946A1
• Time in Patent Office: 1,460 Days
• Field of Search: 704500-504
• 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 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 compares the importance of the main signal of the m-th layer, where m is a natural number from 1 to M, 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 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 transformer 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;

the encoding apparatus is a scalable encoder having M layers, wherein M>

=2;

an m-th layer selector that compares an importance of an m-th layer primary signal with an importance of an m-th layer secondary signal in each layer from a first layer to an M-th layer, and selects a signal of higher importance from the m-th layer primary signal and the m-th layer secondary signal;

an m-th layer encoder that encodes the signal selected in the m-th layer selector, to generate m-th layer encoded data in each layer from the first layer to the M-th layer;

an m-th layer decoder that decodes the m-th encoded data to generate an m-th layer decoded signal in each layer from the first layer to an (M−

1)-th layer;

a subtractor that generates a m-th layer residual signal obtained by subtracting the m-th layer decoded signal from the signal selected in the m-th layer selector, wherein the m-th layer residual signal is used as an (m+1)-th layer primary signal and a signal that has lower importance and is not selected in the m-th layer selector is used as an (m+1)-th layer secondary signal, in each layer from the first layer to the (M−

1)-th layer;

and a transmitter that transmits encoded data of the first layer to the M-th layer and signal information indicating signals selected in selectors in the first layer to the M-th layer.

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

the selector always selects the primary signal in the first layer; and

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

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

the selector 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 transmitter 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. An encoding method for a scalable encoder haying M layers, wherein M>

=2, the method comprising;

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;

comparing and selecting, by comparing an importance of an m-th layer primary signal with an importance of an m-th layer secondary signal in each layer from a first layer to an M-th layer, and selecting a signal of higher importance from the m-th layer primary signal and the m-th layer secondary signal;

encoding the signal selected in the comparing and selecting, to generate m-th layer encoded data in each layer from the first layer to the M-th layer;

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

1)-th layer; and

generating a m-th layer residual signal obtained by subtracting the m-th layer decoded signal from the signal selected in the comparing and selecting, as an (m+1)-th layer primary signal and a signal that has lower importance and is not selected in the comparing and selecting is used as an (m+1)-th layer secondary signal, in each layer from the first layer to the (M−

1)-th layer; and

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