Reversible watermarking using two-way decodable codes
Bijan G. Mobasseri, Domenick Cinalli · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2004
Traditional variable length codes(VLC) used in compressed media are brittle and suffer synchronization loss following bit errors. To counter this situation, resynchronizing VLCs(RVLC) have been proposed to help identify, limit and possibly reverse channel errors. In this work we observe that watermark bits are in effect forced bit errors and are amenable to the application of error-resilient techniques. We have developed a watermarking algorithm around a two-way decodable RVLC. The inherent error control property of the code is now exploited to implement reversible watermarking in the compressed domain. A new decoding algorithm is developed to reestablish synchronization that is lost as a result of watermarking. Resynchronization is achieved by disambiguating among many potential markers that are abundantly emulated in data. The algorithm is successfully applied to several MPEG-2 streams.