Transient audio watermarks resistant to reverberation effects

Abstract

An encoding and decoding method for digital audio watermarking and data hiding in transient acoustic content is disclosed. The audio signal is segmented into overlapping frames and each frame is decomposed into frequency bands. A special transient detector is used to detect frames characterized by transient audio signals (rapidly rising signal amplitude envelope and a relatively broadband spectrum with rapidly evolving spectral content, such as speech fricatives, drum beats, etc.). Frames falling on or containing transients are detected and encoded with binary watermark data by unconditionally hard-modulating the signal frequency band signals according to rules determined by the value of the respective associated binary data bits of the watermark data and without reference to the characteristics of the watermarked band signals. The method is undetectable by human listeners and unusually resistant to the degrading effects of acoustic reverberation.