mlib_SignalLSP2LPC_S16(3MLmediaLib Library Functimlib_SignalLSP2LPC_S16(3MLIB)NAME
mlib_SignalLSP2LPC_S16, mlib_SignalLSP2LPC_S16_Adp - convert line spec‐
tral pair coefficients to linear prediction coefficients
SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ]
#include <mlib.h>
mlib_status mlib_SignalLSP2LPC_S16(mlib_s16 *lpc,
mlib_s32 lscale, const mlib_s16 *lsp, mlib_s32 order);
mlib_status mlib_SignalLSP2LPC_S16_Adp(mlib_s16 *lpc,
mlib_s32 *lscale, const mlib_s16 *lsp, mlib_s32 order);
DESCRIPTION
Each of the functions in this group converts line spectral pair coeffi‐
cients to linear prediction coefficients.
The line spectral pair (LPS) coefficients are defined as the roots of
the following two polynomials:
-(M+1) -1
P(z) = A(z) + z * A(z )
-(M+1) -1
Q(z) = A(z) - z * A(z )
where A(z) is the inverse filter
M -i
A(z) = 1- SUM a(i) * z
i=1
Note that since P(z) is symmetric and Q(z) is antisymmetric all roots
of these polynomials are on the unit circle and they alternate each
other. P(z) has a root at z = -1 (w = PI) and Q(z) has a root at z = 1
(w = 0).
The line spectral frequency (LPF) are the angular frequency of the line
spectral pair (LPS) coefficients.
q = cos(w)
where q is the LPS and w is the LPF.
See Fundamentals of Speech Recognition by Lawrence Rabiner and Biing-
Hwang Juang, Prentice Hall, 1993.
Note for functions with adaptive scaling (with _Adp postfix), the scal‐
ing factor of the output data will be calculated based on the actual
data; for functions with non-adaptive scaling (without _Adp postfix),
the user supplied scaling factor will be used and the output will be
saturated if necessary.
PARAMETERS
Each function takes the following arguments:
lpc The linear prediction coefficients.
lscale The scaling factor of the line spectral pair coefficients,
where actual_data = output_data * 2**(-scaling_factor).
lsp The line spectral pair coefficients in Q15 format.
order The order of the linear prediction filter.
RETURN VALUES
Each function returns MLIB_SUCCESS if successful. Otherwise it returns
MLIB_FAILURE.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOmlib_SignalLPC2LSP_S16(3MLIB), attributes(5)SunOS 5.10 2 Mar 2007 mlib_SignalLSP2LPC_S16(3MLIB)
