Speech classification and parameter weighting used in codebook search
US6493665B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 18, 1998 |
| Grant date | Dec 10, 2002 |
| Priority date | — |
| Expiry date | Sep 18, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L2019/0011
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A multi-rate speech coded supports a plurality of encoding bit rate modes by adaptively selecting encoding bit rate modes to match communication channel restrictions. In higher bit rate encoding modes, an accurate representation of speech through CELP (code excited linear prediction) and other associated modeling parameters are generated for higher quality decoding and reproduction. To support lower bit rate encoding modes, a variety of techniques are applied many of which involve the classification of the input signal. For each bit rate mode selected, pluralities of fixed or innovation subcodebooks are selected for use in generating innovation vectors. The fixed codebook contains pulse subcodebooks and noise-like subcodebooks. To assist in selection of one of the subcodebooks, an adaptive weighting approach is applied in a searching procedure wherein residual classification and various parameters are used to generate a weighting function that is used to favor one subcodebook over another. The pulse subcodebooks are favored to code pulse-like residuals, while the noise-like subcodebooks are favored to code noise-like residuals. The classification may involve identification of noise…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.