A Data Hiding Method for Stereo Audio Signals Using the Polarity of the Inter-Channel Decorrelator

We propose a data hiding algorithm for stereo audio signals which embeds data using the polarity of the reverberations added to the high-frequency channels. We replace the high-frequency components with one middle channel, and embed data as the polarity of reverberations added to each channel in order to adjust the coherence between these channels. Blind detection of embedded data is possible using correlation between the delayed sum and the difference of the high-frequency channels at the detector. Embedded data was detected with little or no errors for added noise at 20 dB SNR and above. MP3 and AAC audio coders were shown not to affect the embedded data as well. The embedded audio quality test using the MUSHRA standard method resulted in little noticeable degradation for almost all sources.