Watermarking of MPEG-2 encoded video without decoding and re-encoding

Embedding information into multimedia data, also called watermarking, is atopic that has gained increased attention recently. For practical applications like authentication and labeling in pay-per-view television broadcasting, watermarking of video, and especially of already encoded video, is interesting. We present a scheme for robust watermarking of MPEG-2 encoded video. The watermark is embedded into the MPEG-3 bitstream, and can be retrieved from the decoded video. The scheme is robust and 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 also applicable to other hybrid coding schemes like MPEG-1, H.261, and H.263.