Predictive split-matrix quantization of spectral parameters for efficient coding of speech
First Claim
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1. A method for jointly quantizing N linear-predictive-coding spectral models per frame of a sampled sound signal, in which N>
- 1, in view of enhancing a spectral-accuracy/coding-rate trade-off in a technique for digitally encoding said sound signal, said method comprising the following combination of steps;
(a) forming a matrix, F, comprising N rows defining N vectors representative of said N linear-predictive-coding spectral models, respectively;
(b) removing from the matrix F a time-varying prediction matrix, P, based on at least one previous frame, to obtain a residual matrix, R; and
(c) vector quantizing said residual matrix R.
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Abstract
The present invention concerns efficient quantization of more than one LPC spectral models per frame in order to enhance the accuracy of the time-varying spectrum representation without compromising on the coding-rate. Such efficient representation of LPC spectral models is advantageous to a number of techniques used for digital encoding of speech and/or audio signals.
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7 Claims
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1. A method for jointly quantizing N linear-predictive-coding spectral models per frame of a sampled sound signal, in which N>
- 1, in view of enhancing a spectral-accuracy/coding-rate trade-off in a technique for digitally encoding said sound signal, said method comprising the following combination of steps;
(a) forming a matrix, F, comprising N rows defining N vectors representative of said N linear-predictive-coding spectral models, respectively; (b) removing from the matrix F a time-varying prediction matrix, P, based on at least one previous frame, to obtain a residual matrix, R; and (c) vector quantizing said residual matrix R. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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5. A method as defined in claim 1, wherein said N linear-predictive-coding spectral models per frame correspond to N sub frames interspersed with m-1 sub frames, m being an integer, and wherein said vectors representative of said linear-predictive-coding spectral models corresponding to said interspersed sub frames are obtained using linear interpolation.
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6. A method as defined in claim 1, further comprising the step of obtaining the time-varying prediction matrix P using a recursive prediction approach.
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7. A method as defined in claim 1, wherein said N linear-predictive-coding spectral models per frame results from a linear-predictive-coding analysis using different window shapes according to the order of a particular spectral model within the frame.
- 1, in view of enhancing a spectral-accuracy/coding-rate trade-off in a technique for digitally encoding said sound signal, said method comprising the following combination of steps;
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