Ordered bitplane watermarking of digital video by direct sequence spread spectrum

Still image watermarking has gained considerable interest. Digital video, however, has received comparatively less attention. In this work we present a formal framework for digital video watermarking. The video signal is modeled as sequence of bitplanes arranged along the time axis. Watermarking of this sequence is a two layer operation. A controlling m-sequence first establishes a pseudorandom order on the bitplanes. This order determines the candidate planes for later watermarking. The watermark itself is a 2D extension of the same or possibly another m-sequence. We have shown that the watermark, when limited to the 4 lowest bitplanes of an 8-bit signal, are unnoticeable. We have also shown that a correlation detector operating over a sequence of frames can extract an embedded watermark at SNR's as low as 0 dB. The watermarked video is also robust to video editing attempts such as subsampling, frame reordering etc. In addition, the watermark is identifiable from arbitrary short segments of video.