High capacity FFT-based audio watermarking

Abstract

This paper proposes a novel high capacity audio watermarking algorithm to embed data and extract it in a bit-exact manner based on changing the magnitudes of the FFT spectrum. The key idea is to divide the FFT spectrum into short frames and change the magnitude value of the FFT samples based on the average of the samples of each frame. Using the average of FFT magnitudes makes it possible to improve the robustness, since the average is more stable against changes compared with single samples. In addition to good capacity, transparency and robustness, this scheme has three parameters which facilitate the regulation of these properties. The experimental results show that the method has a high capacity (0.5 to 4 kbps), without significant perceptual distortion (ODG is about ¿1) and provides robustness against common audio signal processing such as added noise, filtering and MPEG compression (MP3).