Frame-Correlation Exploitation for Secure Audio Watermarking: A Parallel Multi-Watermarking Framework with Enhanced Robustness

To further balance the robustness and imperceptibility of audio watermarking technology and protect the global market information security, this paper proposes an inter-frame correlation-based multiple parallel audio watermarking scheme (ICMP). Adjacent Frame Extraction Process (AFEP) is proposed to select the adjacent frame. Then, Discrete Cosine Transform (DCT) is applied to each embedding frame and its adjacent frame to extract their corresponding frequency domain coefficients. To improve robustness, midfrequency DCT coefficients are selected to embed multiwatermarks. For enhancing embedding capacity, randomly generated vectors are transformed into orthogonal unit vectors using Gram-Schmidt orthogonalization. By projecting each interframe difference coefficient onto orthogonal vectors, multiwatermarks are embedded in parallel by adjusting the projections into a predefined range. Experimental results show that, compared to existing schemes, the proposed scheme generally offers superior imperceptibility and robustness.