Context adaptive variable length decoding system and method
US6646578B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 2002 |
| Grant date | Nov 11, 2003 |
| Priority date | — |
| Expiry date | Nov 22, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/625
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system and method to perform context-adaptive variable length decoding (CAVLC) of transform coefficient levels for block-based motion-compensated decoding of moving pictures, corresponding to transform coefficients. The system and method includes complexity-reduction improvements in the coefficient level decoding process, such as simplified and extended range of Lev-VLC tables. Specifically, the number of Lev-VLC tables is extended from 5 to 7 and only 1 escape code (28-bit escape code) is used for tables Lev-VLC1to Lev-VLC6. The system and method also includes a simplified and improved table selection process. The table selection for the first Coefficient_level after trailing ones depends on total number of non-zero coefficients and number of trailing ones which are local variables within the CAVLC module. The table selection process for subsequent Coefficient_level's has been re-designed in such a way that the same logic path can be used to select Lev-VLC table for the next coefficient regardless of block modes and quantization parameters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.