Patent ID: 8768005

Claim:
A method for extracting a watermark signal from an output signal of a watermarking encoder, the output signal including an input signal portion corresponding to an input signal to the watermarking encoder and a watermark signal portion corresponding to the watermark signal, the method comprising: receiving the input signal and the output signal; generating an adjusted output signal by adjusting gain and delay of the output signal to account for changes in gain and delay in the input signal portion of the output signal introduced by the watermarking encoder or generating an adjusted input signal by adjusting gain and delay of the input signal to account for changes in gain and delay in the input signal portion of the output signal introduced by the watermarking encoder by extracting the phase difference between the input signal and the output signal and extracting the ratio or difference of the magnitudes of the input signal and the output signal; and obtaining the watermark signal from a difference between the input signal and the adjusted output signal or from a difference between the adjusted input signal and the output signal.