An audio digital watermarking algorithm transmitted via air channel in double DCT domain

Based on double DCT transform, an audio digital watermarking algorithm was proposed and transmitted via air channel. The low-frequency coefficients in DCT domain were chosen for the second DCT transform. Using the method of modifying the coefficients in double DCT domain, the watermarking and synchronization signal was embedded into the original audio carrier and with large watermarking capacity. Experimental results indicate that the proposed algorithm has a good hidden effect, and it has very good robustness especially to 30% resample and MP3 compression attacks. Moreover, it can be applied to transmitting situation via air channel, and bit error is from 1.2% to 6.5%.