In this paper, we present a non-blind technique of
adding the watermark to the Fourier spectral components of audio
signal in a way such that the modified amplitude does not exceed the
maximum amplitude spread (MAS). This MAS is due to individual
Discrete fourier transform (DFT) coefficients in that particular frame,
which is derived from the Energy Spreading function given by
Schroeder. Using this technique one can store double the information
within a given frame length i.e. overriding the watermark on the
host of equal length with least perceptual distortion. The watermark
is uniformly floating on the DFT components of original signal.
This helps in detecting any intentional manipulations done on the
watermarked audio. Also, the scheme is found robust to various signal
processing attacks like presence of multiple watermarks, Additive
white gaussian noise (AWGN) and mp3 compression.
 De, A. Multimedia Watermarking in Enhancing Digital Security. ITUT/
ITU-D Workshop, Aug.2001,Banglore.
 Schroeder, M. R., B. S. Atal, and J. L. Hall. Optimizing digital speech
coders by exploiting properties of the human ear. Journal Acoust. Soc.
America, vol. 66, no. 6, pp. 1647-1652, December 1979.
 Su, J. K., F. Hartung, and B. Girod. A channel model for a watermark
attack. In security and watermarking of multimedia contents, , SPIE, Vol.
3657, pp. 159-170, Jan 1999.
 Zwicker, E. and H. Fastl. Psychoacoustics: Facts and Models. Springer-
Verlag, Berlin, Germany, 1990.
 Haykin, S. Communication Systems. 3rd Edition. John Wiley and sons,
 Milleth, J. K., K. Giridhar, and D. Jalihal. Performance enhancement of
space-time trellis codes when encountering AWGN and Ricean channels.
In IEEE Trans. on vehicular technology, Vol. 54, No. 4, July 2005.
 Boney, L., Ahmed H. Tewfic, Khaled N. Hamdy. Digital watermarks
for audio signals. In proceedings of multimedia computing and systems,
 Lee, S. K. and Y. S. Ho Digital audio watermarking in Cepstral Domain.
IEEE Transactions on Consumer Electronics, Vol.46, No.3,August 2000,
 Painter, E. M and A. S. Spanias. A review of algorithms for perceptual
coding of digital audio signals. 13th International Conference on Digital
Signal Processing Proceedings, DSP-97, vol.1,July 1997,pp.179-208.