Largest magnitude indices selection for (run, level) encoding of a block coded picture
US6959116B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 18, 2001 |
| Grant date | Oct 25, 2005 |
| Priority date | — |
| Expiry date | Nov 30, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/007
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Transform coefficients for blocks of pixels in an original picture are quantized to produce respective sets of quantization indices for the blocks of pixels. The quantization indices for at least some of the blocks are produced by using a quantization step size that is not uniform within each block. Largest magnitude quantization indices are selected from the respective sets of quantization indices for (run, level) encoding to produce the (run, level) encoded picture. For example, MPEG-2 coded video includes a set of non-zero AC discrete cosine transform (DCT) coefficients for 8×8 blocks of pixels. For scaling the MPEG-2 coded video, non-zero AC DCT coefficients are removed from the MPEG-2 coded video to produce reduced-quality MPEG-2 coded video that includes no more than a selected number of largest magnitude quantization indices for the non-zero AC DCT coefficients for each 8×8 block.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.