Adaptive audio watermarking algorithm in the hybrid domain

An adaptive blind digital audio watermarking algorithm based on psychoacoustic model is proposed. The scheme jointly exploiting the discrete wavelet packet transform (DWPT) and the discrete cosine transform (DCT) to perform large-capacity blind audio watermarking without introducing perceptible distortion. Each audio frame was divided into 26 sub-band signals by using DWPT. After that, we apply DCT to wavelet packet coefficients and calculate the masking threashold. The masking threshold of each sub-band was used to seek suitable segments and position for watermark embedding. The binary image watermark was embeded into the block middle-frequency and low-frequency DCT coefficients according to quantization index modulation. The quantization step of DCT coefficient in each sub-band was determined by the sub-band ratio of noise to masking threshold .The extraction was executed blindly. Experimental results show that our scheme achieves a good trade-off between robustness, imperceptibility and payload, the watermark capacity range from 576.7bps to 689.5bps,the hidden watermark data is robust to additive noise, requantization, resampling, low-pass filtering, and MP3 compression.