Warped Linear Predictive Coding (Warped LPC or WLPC) is a variant of Linear predictive coding in which the spectral representation of the system is modified, for example by replacing the unit delays used in an LPC implementation with first-order allpass filters. This can have advantages in reducing the bitrate required for a given level of perceived audio quality/intelligibility, especially in wideband audio coding.
History
Warped LPC was first proposed in 1980 by Hans Werner Strube.
References
Oppenheim, A.V.; Johnson, D.H. (1972) Discrete representation of signals, Proceedings of the IEEE, vol. 60, no. 6, pp. 681-691, June 1972
Kruger, E.; Strube, H.W. (1988) Linear prediction on a warped frequency scale, Acoustics, Speech, and Signal Processing [see also IEEE Transactions on Signal Processing], IEEE Transactions on , vol.36, no.9pp.1529-1531, Sep 1988
Laine, U.K.; Karjalainen, M.; Altosaar, T. (1994) Warped linear prediction (WLP) in speech and audio processing, Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on , vol.iii, no.pp.III/349-III/352 vol.3, 19-22 Apr 1994
