High-payload spread spectrum based audio watermarking via M-ary code phase shift keying

This paper presents a method to improve the payload of spread spectrum (SS) based audio watermarking via an M-ary SS modulation technique called code phase shift keying (CPSK), in which the code phase of the spreading sequence is modulated with multiple data bits. Compared with the code division multiple access (CDMA) based watermarking with the same transparency and payload, the proposed scheme provides better robustness against common attacks for large M, and requires lower embedding and extraction complexity.