Digital audio signal coding using a CELP coder and a transform coder
US6134518A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1998 |
| Grant date | Oct 17, 2000 |
| Priority date | — |
| Expiry date | Mar 4, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/04
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Apparatus is described for digitally encoding an input audio signal for storage or transmission. A distinguishing parameter is measure from the input signal. It is determined from the measured distinguishing parameter whether the input signal contains an audio signal of a first type or a second type. First and second coders are provided for digitally encoding the input signal using first and second coding methods respectively and a switching arrangement directs, at any particular time, the generation of an output signal by encoding the input signal using either the first or second coders according to whether the input signal contains an audio signal of the first type or the second type at that time. A method for adaptively switching between transform audio coder and CELP coder, is presented. In a preferred embodiment, the method makes use of the superior performance of CELP coders for speech signal coding, while enjoying the benefits of transform coder for other audio signals. The combined coder is designed to handle both speech and music and achieve an improved quality.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.