REW parametric vector quantization and dual-predictive SEW vector quantization for waveform interpolative coding
View Patent ↗An enhanced analysis-by-synthesis waveform interpolative speech coder able to operate at 2.8 kbps. Novel features include dual-predictive analysis-by-synthesis quantization of the slowly-evolving waveform, efficient parametrization of the rapidly-evolving waveform magnitude, and analysis-by-synthesis vector quantization of the rapidly evolving waveform parameter. Subjective quality tests indicate that it exceeds G.723.1 at 5.3 kbps, and of G.723.1 at 6.3 kbps.
1. A method for interpolative coding input signals, said signals decomposed into or composed of a slowly evolving waveform and a rapidly evolving waveform having a magnitude, the method incorporating at least one of the following steps:
(a) analysis-by-synthesis vector quantization of the rapidly evolving waveform parameter;
(b) parametrizing the magnitude of the rapidly evolving waveform;
(c) incorporating temporal weighting in the AbS VQ of the REW; or
(d) incorporating spectral weighting in the AbS VQ of the REW;
the method either (1) applying a filter to a vector quantizer codebook in the analysis-by-synthesis vector-quantization of the rapidly evolving waveform whereby to add self correlation to the codebook vectors or (2) using a coder in which a plurality of bits therein are allocated to the rapidly evolving waveform magnitude.
2. The method of claim 1 further comprising analysis-by-synthesis vector quantization of the slowly evolving waveform.
3. The method of claim 1 wherein said signal is speech.
4. The method of claim 1 wherein said method incorporates each of steps (a) through (c).
5. A method for interpolative coding input signals, said signals decomposed into or composed of a slowly evolving waveform and a rapidly evolving waveform having a magnitude, comprising:
(a) analysis-by-synthesis vector quantization of the rapidly evolving waveform parameter;
(b) analysis-by-synthesis quantization of the slowly evolving waveform;
(c) parametrizing the magnitude of the rapidly evolving waveform;
(d) incorporating temporal weighting in the analysis-by-synthesis vector quantization of the rapidly evolving waveform; and
(e) incorporating spectral weighting in the analysis-by-synthesis vector quantization of the rapidly evolving waveform
the method either (1) applying a filter to a vector guantizer codebook in the analysis-by-synthesis vector-quantization of the rapidly evolving waveform whereby to add self correlation to the codebook vectors or (2) using a coder in which a plurality of bits therein are allocated to the rapidly evolving waveform magnitude.
6. The method of claim 5 in which in the step of analysis-by-synthesis of a first vector-quantization of the slowly evolving waveform is predicted based on the vector quantization of the rapidly evolving waveform and a second vector quantization of the slowly evolving waveform.
7. A method for interpolative coding input signals, said signals decomposed into or composed of a rapidly evolving waveform, comprising incorporating analysis-by-synthesis vector quantization of the rapidly evolving waveform parameter, the method either (1) applying a filter to a vector guantizer codebook in the analysis-by-synthesis vector-quantization of the rapidly evolving waveform whereby to add self correlation to the codebook vectors or (2) using a coder in which a plurality of bits therein are allocated to the rapidly evolving waveform magnitude.
8. A speech coding system using waveform interpolation comprising at least one of the following steps:
(a) analysis-by-synthesis vector quantization of a rapidly evolving waveform parameter;
(b) parametrizing a magnitude of a rapidly evolving waveform;
(c) incorporating temporal weighting in the AbS VQ of the REW; or
(d) incorporating spectral weighting in the AbS VQ of the REW;
the method either (1) applying a filter to a vector quantizer codebook in the analysis-by-synthesis vector-quantization of the rapidly evolving waveform whereby to add self correlation to the codebook vectors or (2) using a coder in which a plurality of bits therein are allocated to the rapidly evolving waveform magnitude.