Improving Perceptual Quality in Video watermarking using motion estimation

Motion is inherent to video signals, and high perceptual quality cannot be achieved without accounting for motion. Although the information inferred from motion vectors in an encoder does not always represent the true motion of objects, in this paper, we show that it still carries useful information for finding an estimate of motion characteristics. We use the number of copy-mode macroblocks to measure motion intensity, and we use motion history to capture the spatial distribution of motion. By this means, we can identify moving areas in video frames. We do not embed watermark bits in moving areas to avoid watermarking artifacts introduced into P- and B-frames from watermark bits embedded in I-frames. Our simulations show that the proposed algorithm reduces undesirable watermarking artifacts in the video when compared to methods that do not exploit motion information.