Interval width update process in the arithmetic coding method
US5592162A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 23, 1994 |
| Grant date | Jan 7, 1997 |
| Priority date | — |
| Expiry date | Mar 23, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/4006
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention relates to an interval width update process in arithmetic coding, characterized in that PA0 a set of values ={A[0],A[1], . . . ,A[r-1]}, is selected and the interval width is maintained as an index Wi in said set, PA0 a single table lookup simultaneously updates the interval width and supplies the augend and shift by performing the following operation: EQU (Wi+1, Xi, Ri)=.function."(Si, Wi) PA0 in which the function .function." is implemented by a single table lookup, in which p(Si) and P(Si) are determined from Si, A[Wi] is determined from Wi, p(Si).multidot.A[Wi] and Ri=P(Si).multidot.A[Wi] are computed, the shift Xi necessary for representing p(Si).multidot.A[Wi].multidot.2.sup.Xi in is determined. Wi+1 is determined in such a way that A[Wi+1] is the best representative of p(Si).multidot.A[Wi].multidot.2.sup.Xi, followed by return to Wi+1, Xi and Ri.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.