Method of embedding watermarks in a signal encoded by an encoder having a feedback loop, for example, a sigma-delta modulator (21, 22, 23). A digital watermark pattern (w) is embedded in the signal (z) by modifying selected samples (for example, replacing every 100th bit) of the encoded signal (y) by samples of the watermark pattern. The circuit (24) for modifying the samples is located inside the loop of the encoder. The effect of watermarking is thus compensated in subsequent encoding steps and the signal-to-noise ratio is only slightly affected.

Title
Embedding supplemental data in encoded signal
Application Number
98800340
Publication Number
1234944
Application Date
January 12, 1998
Publication Date
November 10, 1999
Inventor
P A C M Nitong
G F G Deboveiry
A A M L Blukers
Agent
wu zengyong
Assignee
Koninclijke Philips Electronics
IPC
H04N 07/50
H04N 07/08