Coding device and coding method with high layer coding based on lower layer coding results

• US 8,306,827 B2
• Filed: 03/08/2007
• Issued: 11/06/2012
• Est. Priority Date: 03/10/2006
• Status: Active Grant

• Current Assignee: III Holdings 12, LLC (Intellectual Ventures LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yamanashi, Tomofumi, Sato, Kaoru, Morii, Toshiyuki, Oshikiri, Masahiro
• Primary Examiner(s): He, Jialong
• Application Number:
  US12/282,287
• Publication Number:
  US 20090094024A1
• Time in Patent Office: 2,070 Days
• Field of Search: 704500-504, 704200-278
• US Class Current: 704/500
• 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

A coding device is provided with features in which optimum coding in a higher layer is flexibly carried out based on a coding result of a lower layer and a quality audio signal in limited circumstances is served to users. In this coding device, a basic layer coding unit codes an input signal to generate a basic layer information source code and outputs a linear prediction coefficient (LPC) and a quantum LPC, which are parameters calculated at coding, to an expanded layer control unit. A basic layer decoding unit decodes the basic layer information source code. An adding unit reverses a polarity of a basic layer decoded signal, adds the same to the input signal, and calculates a difference signal. The expanded layer control unit generates expanded layer mode information indicative of a coding mode in an expanded layer based on the LPC and the quantum LPC. An expanded layer coding unit codes the difference signal obtained from the adding unit under control of the expanded layer control unit.

Claims

1. A coding apparatus that encodes an input signal by information of n layers, where n is an integral number equal to or greater than 2, the apparatus comprising:

a base layer coder that encodes the input signal and generates encoded information of a first layer;

an i-th layer decoder that decodes encoded information of an i-th layer, where i is an integral number between 1 and n−

1, and generates a decoded signal of the i-th layer;

an adder that finds one of a first layer difference signal representing a difference between the input signal and a decoded signal of the first layer, and an i-th layer difference signal representing a difference between a difference signal of an (i−

1)-th layer and a decoded signal of the i-th layer;

a (i+1)-th layer enhancement layer coder that encodes the difference signal of the i-th layer and generates encoded information of a (i+1)-th layer; and

an enhancement layer controller that controls a coding method in a second coder in a higher layer, which is higher than a predetermined layer according to a quantization result of coding parameters for a first coder in the predetermined layer,

wherein one of the coders is a code-excited linear prediction (CELP) type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first linear prediction coefficient (LPC) codebook when an LPC quantization error in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second LPC codebook of a smaller size than the first LPC codebook when the LPC quantization error in the first coder in the predetermined layer is equal to or less than the predetermined threshold.

2. The coding apparatus according to claim 1,

wherein one of the coders is a CELP type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first fixed excitation codebook when an LPC quantization error in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second fixed excitation codebook of a larger size than the first fixed excitation codebook when the LPC quantization error in the first coder in the predetermined layer is equal to or less than the predetermined threshold.

3. The coding apparatus according to claim 1,

wherein one of the coders is a CELP type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first shape codebook when an LPC quantization error in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second shape codebook of a smaller size than the first shape codebook when the LPC quantization error in the first coder in the predetermined layer is equal to or less than the predetermined threshold.

4. The coding apparatus according to claim 1,

wherein one of the coders is a CELP type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first gain codebook when an LPC quantization error in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second gain codebook of a smaller size than the first gain codebook when the LPC quantization error in the first coder in the predetermined layer is equal to or less than the predetermined threshold.

5. The coding apparatus according to claim 1,

wherein one of the coders is a CELP type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first shape codebook when an LPC pitch gain in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second shape codebook of a smaller size than the first shape codebook when the LPC pitch gain in the first coder in the predetermined layer is equal to or less than the predetermined threshold.

6. The coding apparatus according to claim 1,

wherein one of the coders is a CELP type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first gain codebook when an LPC pitch gain in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second gain codebook of a smaller size than the first gain codebook when the LPC pitch gain in the first coder in the predetermined layer is equal to or less than the predetermined threshold.

7. A coding method that encodes an input signal by information of n layers, where n is an integral number greater than 2, comprising:

encoding, by a base layer coder, the input signal and generating encoded information of a first base layer;

decoding, by an i-th layer decoder, encoded information of an i-th layer, where i is an integral number at least equal to 1 and not more than n−

1, and generating a decoded signal of the i-th layer;

finding, by an adder, a difference signal of a first layer representing a difference between the input signal and a decoded signal of the first base layer or a difference signal of an i-th layer representing a difference between a difference signal of a (i−

1) layer and the decoded signal of the i-th layer;

encoding, by an (i+1)-th layer coder, the difference signal of the i-th layer and generating encoded information of a (i+1)-th layer; and

controlling the coding method, by an enhancement layer controller, in a second coder in a higher layer, which is higher than a predetermined layer according to a quantization result of coding parameters of a first coder in the predetermined layer,

wherein one of the coders is a code-excited linear prediction (CELP) type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first linear prediction coefficient (LPC) codebook when an LPC quantization error in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second LPC codebook of a smaller size than the first LPC codebook when the LPC quantization error in the first coder in the predetermined layer is equal to or less than the predetermined threshold.

8. A non-transitory computer-readable storage medium that includes a program that makes a computer perform a coding method that encodes an input signal by encoded information of n layers, where n is an integral number greater than 2, comprising:

encoding, by a base layer coder, the input signal and generating encoded information of a first base layer;

decoding, by an ith layer decoder, encoded information of an i-th layer, where i is an integral number at least equal to 1 and not more than n−

1, and generating a decoded signal of the i-th layer;

finding, by an adder, a difference signal of a first layer representing a difference between the input signal and a decoded signal of the first base layer or a difference signal of an i-th layer representing a difference between a difference signal of a (i−

1) layer and the decoded signal of the i-th layer;

encoding, by an (i+1)-th layer coder, the difference signal of the i-th layer and generating encoded information of a (i+1)-th layer; and

controlling the coding method, by an enhancement layer controller, a second coder in a higher layer, which is higher than a predetermined layer according to a quantization result of coding parameters of a first coder in the predetermined layer,

wherein one of the coders is a code-excited linear prediction (CELP) type coder, and the enhancement layer controller controls the coding method in the second coder in the higher layer than the predetermined layer such that quantization is performed using a first linear prediction coefficient (LPC) codebook when an LPC quantization error in the first coder in the predetermined layer is greater than a predetermined threshold and quantization is performed using a second LPC codebook of a smaller size than the first LPC codebook when the LPC quantization error in the first coder in the predetermined layer is equal to or less than the predetermined threshold.