Two-Channel time-frequency audio watermarking

The time-frequency audio watermarking scheme operates by removing and adding samples to the frequency spectrum of the audio signals (compression-expansion) as a way to embed watermarks. The watermarks so embedded are identified by comparing the waveforms of the original and the watermarked signals. For a single channel signal, the compression-expansion represents one binary symbol and the unchanged frames in between are taken as the other binary symbol. For audio signals with two channels such as stereo music, a method is proposed in this paper so that compression- expansion in the two channels are used to represent different binary symbols In addition, some modifications to the original scheme are also presented.