Warped Linear Predictive Coding

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) [http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1450657 Discrete representation of signals] , Proceedings of the IEEE, vol. 60, no. 6, pp. 681-691, June 1972
* Strube, H.W. (1980) [http://link.aip.org/link/?JASMAN/68/1071/1 Linear prediction on a warped frequency scale] , Journal of the Acoustical Society of America, vol. 68, no. 4, pp. 1071-1076, Oct 1980
* Harma, A.; Laine, U.K. (2001) [http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=928922 A comparison of warped and conventional linear predictive coding] , Speech and Audio Processing, IEEE Transactions on , vol.9, no.5pp.579-588, Jul 2001
* Kruger, E.; Strube, H.W. (1988) [http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=90384 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) [http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=390018 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