difmag.c

sloedgy open sip stack source code

/*

$Log: difmag.c,v $
Revision 1.1  2006/06/26 03:02:52  joegenbaclor
I have decided to include the latest development realease  of OPAL tagged Deimos Devel 1 (June 8 2006) as inegrated classes to opensipstack to avoid future version conflicts due to the fast pace in OPAL development.   This move is also aimed to reduce the size of projects using OPAL componets such as the soon to be relased OpenSIPPhone.

Revision 2.2  2005/08/08 03:28:41  dereksmithies
Eradicate all "/ * within comments" messages from GCC compilations.

Revision 2.1  2003/03/14 09:53:27  robertj
Updated to openH323 v1.11.7

Revision 1.1  2000/06/05 04:45:12  robertj
Added LPC-10 2400bps codec

 * Revision 1.1  1996/08/19  22:32:31  jaf
 * Initial revision
 *

*/

#ifdef P_R_O_T_O_T_Y_P_E_S
extern int difmag_(real *speech, integer *lpita, integer *tau, integer *ltau, integer *maxlag, real *amdf, integer *minptr, integer *maxptr);
#endif

/*  -- translated by f2c (version 19951025).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include "f2c.h"

/* ********************************************************************** */

/* 	DIFMAG Version 49 */

/*
 * $Log: difmag.c,v $
 * Revision 1.1  2006/06/26 03:02:52  joegenbaclor
 * I have decided to include the latest development realease  of OPAL tagged Deimos Devel 1 (June 8 2006) as inegrated classes to opensipstack to avoid future version conflicts due to the fast pace in OPAL development.   This move is also aimed to reduce the size of projects using OPAL componets such as the soon to be relased OpenSIPPhone.
 *
 * Revision 2.2  2005/08/08 03:28:41  dereksmithies
 * Eradicate all "/ * within comments" messages from GCC compilations.
 *
 * Revision 2.1  2003/03/14 09:53:27  robertj
 * Updated to openH323 v1.11.7
 *
 * Revision 1.1  2000/06/05 04:45:12  robertj
 * Added LPC-10 2400bps codec
 *
 * Revision 1.1  1996/08/19  22:32:31  jaf
 * Initial revision
 * */
/* Revision 1.3  1996/03/15  23:09:39  jaf */
/* Just added a few comments about which array indices of the arguments */
/* are used, and mentioning that this subroutine has no local state. */

/* Revision 1.2  1996/03/13  14:41:31  jaf */
/* Comments added explaining that none of the local variables of this */
/* subroutine need to be saved from one invocation to the next. */

/* Revision 1.1  1996/02/07 14:45:04  jaf */
/* Initial revision */


/* ********************************************************************* */

/*  Compute Average Magnitude Difference Function */

/* Inputs: */
/*  SPEECH - Low pass filtered speech */
/*           Indices MIN_N1 through MAX_N1+LPITA-1 are read, where */
/*      MIN_N1 = (MAXLAG - MAX_TAU)/2+1  MAX_TAU = max of TAU(I) for I=1,LTAU
*/
/*      MAX_N1 = (MAXLAG - MIN_TAU)/2+1  MIN_TAU = min of TAU(I) for I=1,LTAU
*/
/*  LPITA  - Length of speech buffer */
/*  TAU    - Table of lags */
/*           Indices 1 through LTAU read. */
/*  LTAU   - Number of lag values to compute */
/*  MAXLAG - Maximum possible lag value */
/* Outputs: */
/*  (All of these outputs are also read, but only after being written.) */
/*  AMDF   - Average Magnitude Difference for each lag in TAU */
/*           Indices 1 through LTAU written */
/*  MINPTR - Index of minimum AMDF value */
/*  MAXPTR - Index of maximum AMDF value */

/* This subroutine has no local state. */

/* Subroutine */ int difmag_(real *speech, integer *lpita, integer *tau, 
	integer *ltau, integer *maxlag, real *amdf, integer *minptr, integer *
	maxptr)
{
    /* System generated locals */
    integer i__1, i__2;
    real r__1;

    /* Local variables */
    integer i__, j, n1, n2;
    real sum;

/*       Arguments */
/*       Local variables that need not be saved */
/*       Local state */
/*       None */
    /* Parameter adjustments */
    --amdf;
    --tau;
    --speech;

    /* Function Body */
    *minptr = 1;
    *maxptr = 1;
    i__1 = *ltau;
    for (i__ = 1; i__ <= i__1; ++i__) {
	n1 = (*maxlag - tau[i__]) / 2 + 1;
	n2 = n1 + *lpita - 1;
	sum = 0.f;
	i__2 = n2;
	for (j = n1; j <= i__2; j += 4) {
	    sum += (r__1 = speech[j] - speech[j + tau[i__]], abs(r__1));
	}
	amdf[i__] = sum;
	if (amdf[i__] < amdf[*minptr]) {
	    *minptr = i__;
	}
	if (amdf[i__] > amdf[*maxptr]) {
	    *maxptr = i__;
	}
    }
    return 0;
} /* difmag_ */