Audio Watermarking Scheme Based on Improved QIM and Residual-Guided Scaling Factor Against Desynchronization Attacks

Traditional audio watermarking schemes do not adequately consider the watermark band misalignment caused by desynchronization attacks, thereby exhibiting vulnerability to such attacks. To address this issue, a novel audio watermarking scheme based on improved quantization index modulation (QIM) and residual-guided scaling factor is proposed. Specifically, the host signal performs discrete cosine transform and singular value decomposition to extract low and medium frequency features with good robustness. Then, the global low-frequency feature information is utilized for quantizer construction, tackling the amplitude scaling-related attacks that classical QIM fails to resist. Next, the chaotic encrypted watermarks are embedded in the mid-frequency features by the improved QIM technique. In the watermark extracting stage, the residual-guided scaling factor is estimated to resist desynchronization attacks. According to the watermark embedding pattern, the misaligned watermark bands caused by the desynchronization attacks are pinpointed by minimizing residuals between the extracted features under different scaling factors and the original watermarked features. After that, the watermark information is directly extracted from these bands. Finally, the performance of the proposed watermarking scheme against desynchronization attacks and common signal processing techniques is theoretically analyzed. Extensive experiments demonstrate that, compared to the state-of-the-art schemes, the proposed scheme provides a more efficient solution to resist desynchronization attacks, while the watermarked audio quality maintains an excellent level.