A Perceptually Adaptive and Retrievable QIM Scheme for Efficient Blind Audio Watermarking

This study proposes a feasible way to incorporate the quantization index modulation (QIM) scheme into a framework jointly formed by the discrete wavelet packet transform (DWPT) and discrete cosine transform (DCT) in the field of audio watermarking. To achieve a balance between the robustness and imperceptibility, an adaptive QIM has been developed under the guidance of the human auditory masking effect while carrying out frame synchronization and watermark embedding. An iterative algorithm is introduced to ensure a precise retrieval of the original quantization step from the watermarked signal without referring to auxiliary information. The effectiveness of the proposed scheme has been proven using the perceptual evaluation of audio quality (PEAQ) and the bit error rates of the recovered watermark under common digital signal processing attacks.