AC-3 bit stream watermarking

摘要

AC-3 audio compression find applications in home cinema, DVD, BD and digital television. This paper addresses the challenge of transparently watermarking AC-3 bit streams instead of the conventional decoding — baseband watermarking — re-encoding approach. We discuss the alternate possibilities to embed watermarks by altering the MDCT coefficients delivered in the bit stream, which consists of mantissas and exponents. We then introduce an AC-3 bit stream watermarking system that is accomplished by solely modifying mantissas to obtain a low computational complexity. We subsequently present the associated watermark detector, which proves to be interoperable with a legacy watermarking system that operates in a different embedding domain. Finally, we compare the proposed bit stream system with the regular decoding — watermarking — re-encoding chain to verify the quality and robustness.