Efficient scaling of nonscalable MPEG-2 Video
US6771703B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2000 |
| Grant date | Aug 3, 2004 |
| Priority date | — |
| Expiry date | Nov 6, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/59
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
To reduce bandwidth of non-scalable MPEG-2 coded video, certain non-zero AC DCT coefficients for the 8×8 blocks are removed from the MPEG-2 coded video. In one implementation, high-frequency AC DCT coefficients are removed at the end of the coefficient scan order. This method requires the least computation and is most desirable if the reduced-bandwidth video is to be spatially sub-sampled. In another implementation, the smallest-magnitude AC DCT coefficients are removed. This method may produce an undesirable increase in the frequency of occurrence of escape sequences in the (run, level) coding. This frequency can be reduced by retaining certain non-zero AC DCT coefficients that are not the largest magnitude coefficients, and by increasing a quantization scale to reduce the coefficient levels. The reduced-bandwidth video can be used for a variety of applications, such as browsing for search and play-list generation, bit stream scaling for splicing, and bit-rate adjustment for services with limited resources and for multiplexing of transport streams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.