Method and apparatus for seamless multi-rate speech coding
US6496794B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1999 |
| Grant date | Dec 17, 2002 |
| Priority date | — |
| Expiry date | Nov 22, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/24
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A communications system (100) includes a multi-rate source coder (MRSC) (102), a variable size/rate buffer (VSRB) (112), a speech buffer (104), and a buffer control block (106). The variable size/rate buffer (112) includes a source coder bit buffer (SCBB) (114) and an adaptive transmit frame buffer (116). The source coder bit buffer (114) receives speech frames coded at different rates from the multi-rate source coder (102), and deposits an integer or non-integer number of frames in the adaptive transmit frame buffer (ATFB) (116). A receiver includes a seamless rate transition module (SRTM) (308) and an variable buffer (310). The seamless rate transition module (308) correlates speech data previously coded at different rates, and it then truncates or alternatively appends, concatenates, and warps the speech data to remove any annoying artifacts at the rate change boundary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.