Patent ID: 6798894
Filing Date: 2004-09-28
Classification: G06K,G06T,G10L,G11B,H04N

Abstract:
A method of introducing a watermark into a stream of bits comprising variable length codes that represent transform domain samples while insuring that a bit rate of said stream of bits is maintained within a pre-established limit, said method comprising, providing a watermark signal comprising changes to associated transform domine samples to embed the watermark signal in the samples, maintaining a cumulative change amount which indicates an amount of the positive and negative changes which are made to said codes as a result of embedding the watermark signal, adjusting the watermark signal changes to particular transform samples such that the amount of the adjustment and the change to the particular transform samples is non-zero yet the cumulative change amount is maintained below the pre-established limit, and suspending positive changes if the cumulative change amount exceeds the pre-established limit, whereby the bit rate of said stream of bits is maintained within the pre-established limit.