Digital signal compression encoding with improved quantisation
US6668088B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Nov 29, 1999 |
| Grant date | Dec 23, 2003 |
| Priority date | — |
| Expiry date | Nov 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In compression encoding of a digital signal, such as MPEG2, transform coefficients are quantised with the lower bound of each interval being controlled by a parameter &lgr;. In the MPEG2 reference coder, for example, &lgr;=0.75. Because the quantised coefficients are variable length coded, improved quality or reduced bit rates can be achieved by controlling &lgr; so as to vary dynamically the bound of each interval with respect to the associated representation level. The parameter &lgr; can vary with coefficient amplitude, with frequency, or with quantisation step size. In a transcoding operation, &lgr; can also vary with parameters in the initial coding operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.