123 lines
3.3 KiB
C
123 lines
3.3 KiB
C
/*
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$Log: difmag.c,v $
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Revision 1.1 2004/05/04 11:16:42 csoutheren
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Initial version
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Revision 1.1 2000/06/05 04:45:12 robertj
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Added LPC-10 2400bps codec
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* Revision 1.1 1996/08/19 22:32:31 jaf
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* Initial revision
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*
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*/
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#ifdef P_R_O_T_O_T_Y_P_E_S
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extern int difmag_(real *speech, integer *lpita, integer *tau, integer *ltau, integer *maxlag, real *amdf, integer *minptr, integer *maxptr);
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#endif
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/* -- translated by f2c (version 19951025).
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You must link the resulting object file with the libraries:
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-lf2c -lm (in that order)
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*/
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#include "f2c.h"
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/* ********************************************************************** */
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/* DIFMAG Version 49 */
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/* $Log: difmag.c,v $
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* Revision 1.1 2004/05/04 11:16:42 csoutheren
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* Initial version
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*
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* Revision 1.1 2000/06/05 04:45:12 robertj
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* Added LPC-10 2400bps codec
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*
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* Revision 1.1 1996/08/19 22:32:31 jaf
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* Initial revision
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*
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*/
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/* Revision 1.3 1996/03/15 23:09:39 jaf */
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/* Just added a few comments about which array indices of the arguments */
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/* are used, and mentioning that this subroutine has no local state. */
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/* Revision 1.2 1996/03/13 14:41:31 jaf */
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/* Comments added explaining that none of the local variables of this */
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/* subroutine need to be saved from one invocation to the next. */
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/* Revision 1.1 1996/02/07 14:45:04 jaf */
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/* Initial revision */
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/* ********************************************************************* */
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/* Compute Average Magnitude Difference Function */
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/* Inputs: */
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/* SPEECH - Low pass filtered speech */
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/* Indices MIN_N1 through MAX_N1+LPITA-1 are read, where */
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/* MIN_N1 = (MAXLAG - MAX_TAU)/2+1 MAX_TAU = max of TAU(I) for I=1,LTAU
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*/
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/* MAX_N1 = (MAXLAG - MIN_TAU)/2+1 MIN_TAU = min of TAU(I) for I=1,LTAU
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*/
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/* LPITA - Length of speech buffer */
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/* TAU - Table of lags */
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/* Indices 1 through LTAU read. */
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/* LTAU - Number of lag values to compute */
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/* MAXLAG - Maximum possible lag value */
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/* Outputs: */
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/* (All of these outputs are also read, but only after being written.) */
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/* AMDF - Average Magnitude Difference for each lag in TAU */
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/* Indices 1 through LTAU written */
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/* MINPTR - Index of minimum AMDF value */
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/* MAXPTR - Index of maximum AMDF value */
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/* This subroutine has no local state. */
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/* Subroutine */ int difmag_(real *speech, integer *lpita, integer *tau,
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integer *ltau, integer *maxlag, real *amdf, integer *minptr, integer *
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maxptr)
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{
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/* System generated locals */
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integer i__1, i__2;
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real r__1;
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/* Local variables */
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integer i__, j, n1, n2;
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real sum;
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/* Arguments */
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/* Local variables that need not be saved */
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/* Local state */
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/* None */
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/* Parameter adjustments */
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--amdf;
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--tau;
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--speech;
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/* Function Body */
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*minptr = 1;
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*maxptr = 1;
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i__1 = *ltau;
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for (i__ = 1; i__ <= i__1; ++i__) {
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n1 = (*maxlag - tau[i__]) / 2 + 1;
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n2 = n1 + *lpita - 1;
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sum = 0.f;
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i__2 = n2;
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for (j = n1; j <= i__2; j += 4) {
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sum += (r__1 = speech[j] - speech[j + tau[i__]], abs(r__1));
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}
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amdf[i__] = sum;
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if (amdf[i__] < amdf[*minptr]) {
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*minptr = i__;
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}
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if (amdf[i__] > amdf[*maxptr]) {
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*maxptr = i__;
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}
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}
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return 0;
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} /* difmag_ */
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