A method of placing a watermark in a video stream estimates motion between
frames in the video stream, and computes a representative motion for a
frame. Before embedding the watermark in that frame, the method spatially
adjusts a digital watermark by the representative motion. This method is
particularly suited for embedding a watermark in a video stream
compressed using motion estimation. In this case, the method uses the
motion vectors in the video stream to compute a dominant motion for a
frame, and then shifts the watermark by this dominant motion before
embedding it in the frame.