US 6,606,591 B1 · Speech coding employing hybrid linear prediction coding

Abstract

A speech coding system that employs hybrid linear prediction coding during extraction of linear prediction coefficients within ITU-Recommendation speech coding standards. The present invention is operable within linear prediction speech coding systems including code-excited linear prediction speech coding systems, and it provides for a substantially improved perceptual quality of reproduced speech signals when compared to conventional speech coding methods that employ the commonly known auto-correlation method that is based on minimizing the linear prediction coding (LPC) prediction error energy. The invention is operable to provide for high perceptual quality of reproduced speech signals having substantial differences of energy in various frequency bands. For example, for speech signals having information dispersed broadly across the frequency spectrum, such as having a significant amount of information at low frequency and a significant amount of information at high frequency, the invention provides a way to maintain a high perceptual quality across the broad frequency range. The invention generates a single set of linear prediction coefficients (LPCs) either directly from the speech signal in certain embodiments of the invention, or alternatively, interveningly through the use of line spectral frequencies (LSFs) that are generated from different sets of linear prediction coefficients (LPCs) generated from the speech signal itself in other embodiments of the invention.

Claims27

Dependent claims

A speech codec that performs linear prediction speech coding on a speech signal, the speech codec comprising:

an encoder circuitry, the speech signal provided to the encoder circuitry;
a decoder circuitry communicatively coupled to the encoder circuitry;
a communication link configured to communicatively couple the encoder circuitry and the decoder circuitry;
a linear prediction coefficient parameter extraction circuitry configured to extract at least two sets of linear prediction coefficients during the coding of the speech signal, the linear prediction coefficient parameter extraction circuitry comprising:
a first speech signal processing circuitry configured to extract a first set of linear prediction coefficients representative of a first emphasized component of the speech signal in a speech signal frame;
and
a second speech signal processing circuitry configured to extract a second set of linear prediction coefficients representative of a second emphasized component of the speech signal in the speech signal frame;
and
a linear prediction coefficient combination circuitry configured to combine the first and second sets of linear prediction coefficients to generate a single set of linear prediction coefficients comprising a hybrid of the first and second sets of linear prediction coefficients.

6 more elements

A speech coding system that performs hybrid extraction of linear prediction coefficients during.coding of a speech signal, the speech coding system comprising:

a linear prediction coefficient parameter extraction circuitry configured to extract at least two sets of linear prediction coefficients during the coding of the speech signal in a speech signal frame, at least one of the at least two sets of linear prediction coefficients generated from a pre-emphasized component of the speech signal based on a speech signal characteristic of the speech signal in the speech signal frame;
and
a linear prediction coefficient combination circuitry configured to combine the at least two sets of linear prediction coefficients to generate a single set of linear prediction coefficients comprising a hybrid of the at least two sets of linear prediction coefficients.

A method that performs hybrid extraction of linear prediction coefficients from a speech signal, the method comprising:

calculating a first set of linear prediction coefficients from the speech signal in a speech signal frame;
calculating a second set of linear prediction coefficients from the speech signal in the speech frame, at least one of the at least two sets of linear prediction coefficients generated from a pre-emphasized component of the speech signal based on a speech signal characteristic of the speech signal;
and
combining the first and second sets of linear prediction coefficients to generate a single set of linear prediction coefficients comprising a hybrid of the first and second sets of linear prediction coefficients.

1 more element

Dependencies are inferred from the claim text.

Speech coding employing hybrid linear prediction coding

Life of this patent

Speech coding employing hybrid linear prediction coding

Life of this patent

Abstract

Claims27