Method and apparatus for encoding symbols carrying payload data for watermarking an audio or video signal, and method and apparatus for decoding symbols carrying payload data of a watermarked audio or video signal
US7634031B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 2006 |
| Grant date | Dec 15, 2009 |
| Priority date | — |
| Expiry date | Sep 30, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0202
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Watermark information (denoted WM) consists of several symbols which are embedded continuously in an audio or a video signal. At decoder site the WM is regained using correlation of the received signal with an m-sequence if Spread Spectrum is used. According to the invention, each WM symbol carries an identification data ID item in addition to its normal payload, and it is already tested in the encoder whether or not the signal is good enough so that the embedded symbol can be recovered at decoder side. If true, it is embedded. If not true, no WM is embedded for the length of one symbol and the test is repeated for the following symbol. The sequence of IDs is known at the encoder which can therefore detect using the ID whether or not a symbol has been skipped.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.