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Method and system for line spectral frequency vector quantization in speech codec

A technology of speech coder and code vector, which is applied in the direction of speech analysis, instrumentation, advanced technology, etc., and can solve the problem that the code vector is not optimal

Inactive Publication Date: 2006-02-08
NOKIA TECH OY
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However, the resulting encoded vector may not be optimal

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  • Method and system for line spectral frequency vector quantization in speech codec
  • Method and system for line spectral frequency vector quantization in speech codec
  • Method and system for line spectral frequency vector quantization in speech codec

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Embodiment Construction

[0091] The spectral (pair) parameter vector is a vector representing linear prediction coefficients so that a stable spectral (pair) vector is always ordered. Such representations include line spectral frequency (LSF), line spectral pair (LSP), immittance spectral frequency (ISF), immittance spectral pair (ISP), etc. For the sake of simplicity, the present invention is described by taking LSF expression as an example.

[0092] image 3 A LSF quantization system 40 according to the present invention is shown. remove Figure 1a In addition to the system components shown, a sorting unit 20 is arranged between the summing unit 16 and the summing unit 18 . The sorting unit 20 is used to quantize the LSF coefficient qLSF i k Rearrange so that they are in ascending order of frequency. For example, if Figure 2a And as shown in 2b, the quantized LSF coefficient qLSF 1 k and qLSF 2 k Already sorted in ascending order, i.e. qLSF i 1 i 2 i 3 , so the function of the sorting...

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Abstract

A method and system for quantizing LSF vectors in a speech coder, wherein predicted LSF values based on previously decoded output values are used to estimate spectral distortion, along with the residual codebook vectors and the LSF coefficients. The method comprises the steps of obtaining a plurality of quantized LSF coefficients from the respective predicted LSF values and the residual codebook vectors; rearranging the quantized LSF coefficients in the frequency domain in an orderly fashion; obtaining the spectral distortion from the rearranged quantized LSF coefficients and the respective LSF coefficients; and an optimal code vector is selected based on the spectral distortion.

Description

technical field [0001] The present invention mainly relates to the coding of speech and audio signals, and in particular to the quantization of linear prediction coefficients in the frequency domain of line spectrum. Background technique [0002] Speech audio coding algorithms are widely used in communication, multimedia and memory systems. It is this need to preserve the high quality of the composite signal while saving transmission and storage capacity that drives the development of encoding algorithms. The complexity of the encoder is limited by the processing power of the application platform. In some applications such as speech storage applications, the encoder can be very complex and the decoder should be as simple as possible. [0003] In a typical speech coder, the input speech signal is processed in segments, called frames. Typical frame lengths are 10-30 milliseconds, and a 5-15 millisecond preamble in subsequent frames is also available. A frame can be further...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G10L19/12G10L19/04G10L19/00G10L19/06
CPCG10L19/07G10L19/038
Inventor A·雷莫
Owner NOKIA TECH OY