Abstract: An audio sonic watermarking algorithm was proposed based on double DCT transform. The low-frequency coefficients after the first DCT transform were chosen for the second DCT transform. Using the method of modifying the coefficients in the double DCT domain, watermarking was embedded and in large quantities. 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, with bit error ranging from 12% to 65%.

Key words: digital watermarking, AD/DA conversion, DCT transform, synchronization signal