mlib_signallpccovariancefree_s16(3mlib) [sunos man page]

mlib_SignalLPCCovarianceFree_S16(3MLIB) 		    mediaLib Library Functions			   mlib_SignalLPCCovarianceFree_S16(3MLIB)

NAME

       mlib_SignalLPCCovarianceFree_S16, mlib_SignalLPCCovarianceFree_F32 - clean up for covariance method

SYNOPSIS

       cc [ flag... ] file... -lmlib [ library... ]
       #include <mlib.h>

       void mlib_SignalLPCCovarianceFree_S16(void *state);

       void mlib_SignalLPCCovarianceFree_F32(void *state);

DESCRIPTION

       Each of these functions frees the internal state structure for covariance method of linear predictive coding (LPC).

       This function cleans up the internal state structure and releases all memory buffers.

PARAMETERS

       Each of the functions takes the following arguments:

       state	       Pointer to the internal state structure.

RETURN VALUES

       None.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       mlib_SignalLPCCovarianceInit_S16(3MLIB),  mlib_SignalLPCCovarianceInit_F32(3MLIB),  mlib_SignalLPCCovariance_S16(3MLIB),  mlib_SignalLPCCo-
       variance_S16_Adp(3MLIB), mlib_SignalLPCCovariance_F32(3MLIB), attributes(5)

SunOS 5.10							    9 Nov 2004				   mlib_SignalLPCCovarianceFree_S16(3MLIB)

mlib_SignalLPCCovariance_S16(3MLIB)			    mediaLib Library Functions			       mlib_SignalLPCCovariance_S16(3MLIB)

NAME

       mlib_SignalLPCCovariance_S16, mlib_SignalLPCCovariance_S16_Adp - perform linear predictive coding with covariance method

SYNOPSIS

       cc [ flag... ] file... -lmlib [ library... ]
       #include <mlib.h>

       mlib_status mlib_SignalLPCCovariance_S16(mlib_s16 *coeff, mlib_s32 cscale, const mlib_s16 *signal, void *state);

       mlib_status mlib_SignalLPCCovariance_S16_Adp(mlib_s16 *coeff, mlib_s32 *cscale, const mlib_s16 *signal, void *state);

DESCRIPTION

       Each function performs linear predictive coding with covariance method.

       In linear predictive coding (LPC) model, each speech sample is represented as a linear combination of the past M samples.

		    M
	    s(n) = SUM a(i) * s(n-i) + G * u(n)
		   i=1

       where  s(*)  is the speech signal, u(*) is the excitation signal, and G is the gain constants, M is the order of the linear prediction fil-
       ter. Given s(*), the goal is to find a set of coefficient a(*) that minimizes the prediction error e(*).

			   M
	    e(n) = s(n) - SUM a(i) * s(n-i)
			  i=1

       In covariance method, the coefficients can be obtained by solving following set of linear equations.

	     M
	    SUM a(i) * c(i,k) = c(0,k), k=1,...,M
	    i=1

       where

		     N-k-1
	    c(i,k) =  SUM s(j) * s(j+k-i)
		      j=0

       are the covariance coefficients of s(*), N is the length of the input speech vector.

       Note that the covariance matrix R is a symmetric matrix, and the equations can be solved efficiently with Cholesky decomposition method.

       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 scaling 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:

       coeff	       The linear prediction coefficients.

       cscale	       The scaling factor of the linear prediction coefficients, where actual_data = output_data * 2**(-scaling_factor).

       signal	       The input signal vector with samples in Q15 format.

       state	       Pointer to the internal state structure.

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	     |Evolving			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       mlib_SignalLPCCovarianceInit_S16(3MLIB), mlib_SignalLPCCovarianceFree_S16(3MLIB), attributes(5)

SunOS 5.10							    10 Nov 2004 			       mlib_SignalLPCCovariance_S16(3MLIB)