Reversible watermarking for compressed speech

Reversible watermarking for compressed speech is proposed. Two properties of parameter-based speech coding bitstream are pointed out. Based on the properties, unimportant parameters are further compressed by entropy coding and concatenated with the watermark payload. The proposed scheme is demonstrated with G.729 speech coding and can be applied to other speech coding standards. Experiment results show that this method can achieve transparent quality of marked speech and a fairly high embedding rate.