| 摘要 |
A method and arrangement are disclosed for embedding a watermark (W) in a media signal (MP) comprising signal samples (x(n)) being encoded as variable-length code words (VLC). The variable-length coded DCT coefficients of an MPEG2 video signal constitute such a media signal. The watermark is embedded by inverting the signs of the AC coefficients as far as such an inversion indeed causes the coefficients to be increased or decreased as prescribed (s(n)) by the watermark to be embedded. The invention is simple to implement, does not require re-encoding of the signal and does not affect the bit rate of the bit stream. |
