Warped linear predictive coding (warped LPC or WLPC) is a variant of
linear predictive coding
Linear predictive coding (LPC) is a method used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive mod ...
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
all-pass filter
An all-pass filter is a signal processing filter that passes all frequencies equally in gain, but changes the phase relationship among various frequencies. Most types of filter reduce the amplitude (i.e. the magnitude) of the signal applied to i ...
s. This can have advantages in reducing the bitrate required for a given level of perceived audio quality/intelligibility, especially in
wideband
In communications, a system is wideband when the message bandwidth significantly exceeds the coherence bandwidth of the channel. Some communication links have such a high data rate that they are forced to use a wide bandwidth; other links ma ...
audio coding.
History
Warped LPC was first proposed in 1980 by Hans Werner Strube.
References
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Digital signal processing
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