mlib_SignalLPC2LSP_S16(3MLIB) mediaLib Library Functions mlib_SignalLPC2LSP_S16(3MLIB)
NAME
mlib_SignalLPC2LSP_S16 - convert linear prediction coefficients to line spectral pair coefficients
SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ]
#include <mlib.h>
mlib_status mlib_SignalLPC2LSP_S16(mlib_s16 *lsp, const mlib_s16 *lpc, mlib_s32 lscale, mlib_s32 order);
DESCRIPTION
The mlib_SignalLPC2LSP_S16() function converts linear prediction coefficients to line spectral pair 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.
PARAMETERS
The function takes the following arguments:
lsp The line spectral pair coefficients in Q15 format.
lpc The linear prediction coefficients.
lscale The scaling factor of the linear prediction coefficients, where actual_data = input_data * 2**(-scaling_factor).
order The order of the linear prediction filter.
RETURN VALUES
The 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 |Evolving |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO
mlib_SignalLSP2LPC_S16(3MLIB), attributes(5)
SunOS 5.10 10 Nov 2004 mlib_SignalLPC2LSP_S16(3MLIB)