Digital video data can be copied repeatedly without loss of quality. Therefore, copyright protection of video data is a more important issue in digital video delivery networks than it was with analog TV broadcast. One method of copyright protection is the addition of a "watermark" to the video signal which carries information about sender and receiver of the delivered video. Therefore, watermarking enables identification and tracing of different copies of video data. Applications are video distribu?tion over the World Wide Web (WWW), pay-per-view video broadcast, or labeling of video discs and video tapes. In the mentioned applicati?ons, the video data is usually stored in compressed format. Thus, the watermark must be embedded in the compressed domain. We present a scheme for robust watermarking of MPEG-2 encoded video. The scheme is of much lower complexity than a complete decoding process followed by watermarking in the pixel domain and re-encoding. Although an existing MPEG-2 bitstream is partly altered, the scheme avoids drift by adding a drift compensation signal. The scheme has been implemented and the results confirm that a robust watermark can be embedded into MPEG encoded video which can be used to securely transmit arbitrary binary information at a data rate of several bytes/second, The scheme is easily applicable to other video coding schemes like MPEG-1, H.261, and H.263.
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