WATERMARKING OF UNCOMPRESSED AND COMPRESSED VIDEO

In this paper, methods for embedding additive digital watermarks into uncompressed and compressed video sequences are presented. The basic p rinciple borrows from spread spectrum communications. It consists of a ddition of an encrypted, pseudo-noise signal to the video that is invi sible, statistically unobtrusive, and robust against manipulations. Fo r practical applications, watermarking schemes operating on compressed video are desirable. A method for watermarking of MPEG-2 encoded vide o is presented. The scheme is a compatible extension of the scheme ope rating on uncompressed video. The watermark is generated exactly in th e same manner as for uncompressed video, transformed using the discret e cosine transform (DCT) and embedded into the MPEG-2 bit-stream witho ut increasing the bit-rate. The watermark can be retrieved from the de coded video and without knowledge of the original, unwatermarked video . Although an existing MPEG-2 bit-stream is partly altered, the scheme avoids visible artifacts by addition of a drift compensation signal. The proposed method is robust and of much lower complexity than a comp lete decoding process followed by watermarking in the pixel domain and re-encoding. Fast implementations exist which have a complexity compa rable to a video decoder. Experimental results are given. The scheme i s also applicable to other hybrid transform coding schemes like MPEG-1 , MPEG-4, H.261, and H.263. (C) 1998 Elsevier Science B.V. All rights reserved.