A Robust Audio Watermarking Algorithm Based on DCT and Vector Quantization

In this paper, a novel robust audio watermarking algorithm based on discrete cosine transform (DCT) and vector quantization (VQ) is proposed. The original audio signal is first segmented into frames. The embedding process for each frame is as follows. First, the original frame is DCT transformed, and several middle-frequency coefficients are composed of a vector to be modified. Then the labeled-codeword based VQ is used to quantize this vector according to the watermark bit to be embedded. Finally, the modified middle-frequency coefficients together with the untouched coefficients are inversely DCT transformed to get the watermarked frame. Experimental results show that the proposed watermarking algorithm has strong robustness to not only most of the attacks in stir mark benchmark for audio but also the cropping attack.