Embedding watermarks into compressed video data
US6373960B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 6, 1998 |
| Grant date | Apr 16, 2002 |
| Priority date | — |
| Expiry date | Jan 6, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0081
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A for method watermarking a compressed video bitstream selects for modification numerous sites within an MPEG compressed video bitstream, each of which sites includes a DCT coefficient which is apt for modification. Watermarking sites are preferably located in MPEG B frames, and the DCT coefficient to be modified preferably has a run-length of zero (0). The method then embeds the watermark by modifying the DCT coefficient for at least some of the selected sites. A list specifying the watermarking sites may be transmitted together with the compressed video bitstream to permit further watermarking by subsequent bitstream receivers. A system for detecting an unauthorized copy of a watermarked video forms a synchronized, frame-by-frame difference between a possibly unauthorized copy of the watermarked compressed video and an un-watermarked copy of the video. Data in the watermarking site list permits readily locating watermarks within the possibly unauthorized copy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.