Methods and apparatuses for variable dimension vector quantization

• US 20070118365A1
• Filed: 01/16/2007
• Published: 05/24/2007
• Est. Priority Date: 03/04/2003
• Status: Abandoned Application

• Current Assignee: Wai Chu
• Original Assignee: Wai Chu
• Inventors: Chu, Wai
• Application Number:
  US11/654,122
• Publication Number:
  US 20070118365A1
• Time in Patent Office: Days
• US Class Current: 704/219
• CPC Class Codes: G10L 19/08 Determination or coding of the excitation function; Determination or coding of the long-term prediction parameters
• CPC Class Codes: G10L 2019/0004 Design or structure of the codebook

Abstract

Improved variable dimension vector quantization-related (“VDVQ-related”) processes have been developed that provide quality improvements over known coding processes in codebook optimization and the quantization of harmonic magnitudes that can be applied to a broad range of distortion measures, including those that would involve inverting a singular matrix using known centroid computation techniques. The improved VDVQ-related processes improve the way in which actual codevectors are extracted from the codevectors of the codebook by redefining the index relationship and using interpolation to determine the actual codevector elements when the index relationship produces a non-integer value. Additionally, these processes improve the way in which codebooks are optimized using the principles of gradient-descent. These improved VDVQ-related processes can be implemented in various software and hardware implementations.

Claims

1. A method for harmonic coding that produces an encoded bit-stream from an input signal, comprising:

determining at least one linear prediction coefficient for the input signal s[n] using linear prediction analysis;

producing an excitation signal u[n] using the at least one linear prediction coefficient and the input signal;

determining at least one pitch period T_k and at least one harmonic magnitude x_k of the excitation signal u[n], wherein the at least one harmonic magnitude x_k includes at least one harmonic magnitude element x_k,j and a variable harmonic magnitude dimension N(T_k);

determining other parameters using the linear prediction coefficients; and

quantizing the other parameters, the pitch period and the at least one harmonic magnitude x_k to produce an encoded bit-stream, wherein the at least one harmonic magnitude is quantized using an improved variable dimension vector quantization procedure.

2. A computer readable storage medium storing computer readable program code for harmonic coding of an input signal, comprising:

data encoding a codebook, wherein the codebook includes at least one codevector y_i and wherein each of the at least one codevectors y_i includes a codevector magnitude N_v and at least one codevector element y_i,m; and

a computer code implementing a method for harmonic coding in response to the input signal, wherein the method for harmonic coding includes;

determining at least one linear prediction coefficient for the input signal s[n] using linear prediction analysis;

producing an excitation signal u[n] using the at least one linear prediction coefficient and the input signal;

determining at least one pitch period T_k and at least one harmonic magnitude x_k of the excitation signal u[n], wherein the at least one harmonic magnitude x_k includes at least one harmonic magnitude element x_k,j and a variable harmonic magnitude dimension N(T_k);

determining other parameters using the linear prediction coefficients; and

quantizing the other parameters, the pitch period and the at least one harmonic magnitude x_k to produce an encoded bit-stream, wherein the at least one harmonic magnitude is quantized using an improved variable dimension vector quantization procedure.

3. An optimized harmonic coder for encoding an input signal s[n] as an encoded bit-stream, comprising:

a linear prediction analysis device, wherein the linear prediction analysis device receives the input signal and produces a plurality of linear prediction coefficients;

an other processing device coupled to the linear prediction analysis device, wherein the other processing device produces at least one other parameter;

an inverse filter defined by the plurality of LP coefficients;

wherein the inverse filter receives the input signal, is coupled to the linear prediction analysis device receiving the linear prediction coefficients therefrom, and produces an excitation signal;

a harmonic analysis device coupled to the inverse filter and receiving the excitation signal therefrom, wherein the harmonic analysis device produces a pitch period T and at least one harmonic magnitude x_j, wherein the harmonic magnitude includes a variable harmonic dimension N(T_k); and

a variable dimension vector quantizer coupled to the harmonic analysis device and the other processing device, wherein the variable dimension vector quantizer receives the pitch period T and the at least one harmonic magnitude x_j from the harmonic analysis device, and receives the other parameters from the other processing device;

wherein the variable dimension vector includes a codebook which includes at least one codevector y_i and wherein the at least one codevector y_i includes a codevector dimension N_v and at least one codebook element y_i,m;

and wherein the variable dimension vector quantizer quantizes the pitch period, the at least one other parameter and the at least one harmonic magnitude x_j to produce the encoded bit-stream, wherein quantizing the at least one harmonic magnitude x_j, includes;

determining at least one linear prediction coefficient for the input signal s[n] using linear prediction analysis;

producing an excitation signal u[n] using the at least one linear prediction coefficient and the input signal;

determining at least one pitch period T_k and at least one harmonic magnitude x_k of the excitation signal u[n], wherein the at least one harmonic magnitude x_k includes at least one harmonic magnitude element x_k,j and a variable harmonic magnitude dimension N(T_k);

determining other parameters using the linear prediction coefficients; and

quantizing the other parameters, the pitch period and the at least one harmonic magnitude x_k to produce an encoded bit-stream, wherein the at least one harmonic magnitude is quantized using an improved variable dimension vector quantization procedure.