Re-synchronizing Audio Watermarking after Non-linear Time Stretching

Stefan Nürnberger, Sascha Zmudzinski, Martin Steinebach

In: Proceedings SPIE 7880, Media Watermarking, Security, and Forensics. Media Watermarking, Security, and Forensics January 23 San Francisco CA United States 7880 SPIE 2011.


Digital audio watermarking today is robust to many common attacks, including lossy compression and digital-to-analogue conversion. One robustness and security challenge, still, is time-stretching. This operation speeds up or slows down the playback speed while preserving the tone pitch. Although inaudible for an uninformed listener if smoothly applied, time-stretching can be confusing for a blind watermark detection algorithm. We introduce a non-blind approach for reconstructing the original timing based on dynamic time warping. Our experiments show that the approach is successful even if non-linear stretching was applied. Our solution can significantly increase the robustness and security of every audio watermarking scheme that is dependent on precise timing conditions at detection time.

nuernberger2011spie_watermarking.pdf (pdf, 272 KB)

Deutsches Forschungszentrum für Künstliche Intelligenz
German Research Center for Artificial Intelligence