Method of architecture for converting MPEG-2 4:2:2-profile bitstreams into main-profile bitstreams
US6259741A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 1999 |
| Grant date | Jul 10, 2001 |
| Priority date | — |
| Expiry date | Feb 18, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/40
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system for converting the color format of a digital video bitstream. The system accounts for the allowable formats of the pre- and-post-conversion bitstreams, including quantizer precision level, and whether luma and chroma data have separate quantization matrices, or share a common quantization matrix. In a particular implementation, an MPEG-2 4:2:2 P bitstream having a color format of 4:2:2 or 4:2:0 is converted to a MP bitstream having a color format of 4:2:0. Coding efficiencies are achieved by using the luma quantization matrix to re-quantize the chroma data, and re-using luma motion vectors for performing motion compensation of the chroma data. Further efficiencies can be achieved by representing a 4:2:2 reference picture in a 4:2:0 format for converting inter coded frames, and changing the position of a pixel downsizing filter and clip function. Adjustment of the quantization precision is provided as required. A transcoding function can also be achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.