Refined entropy coding for level maps
US10484695B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 2017 |
| Grant date | Nov 19, 2019 |
| Priority date | — |
| Expiry date | Dec 5, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/122
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Coding using level maps is disclosed. A method includes coding a scan position, in a forward scan direction, corresponding to an end-of-block and coding, in a backward scan direction, a non-zero map indicating positions of the transform block containing non-zero transform coefficients. The method also includes coding, in the backward scan direction, lower-range level maps, each lower-range level map having a respective map level up to a maximum map level, the lower-range level map indicating which absolute values of the non-zero transform coefficients are equal to the respective map level and which absolute values of the non-zero transform coefficients are greater than the respective map level. The method also includes coding a coefficient residual map, each residual coefficient of the coefficient residual map corresponding to a respective non-zero transform coefficient of the transform block having an absolute value exceeding the maximum map level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.