codecs/lpc10/irc2pc.c

   1 /*
   2
   3 $Log$
   4 Revision 1.15  2004/06/26 03:50:14  markster
   5 Merge source cleanups (bug #1911)
   6
   7 Revision 1.14  2003/02/12 13:59:15  matteo
   8 mer feb 12 14:56:57 CET 2003
   9
  10 Revision 1.1.1.1  2003/02/12 13:59:15  matteo
  11 mer feb 12 14:56:57 CET 2003
  12
  13 Revision 1.2  2000/01/05 08:20:39  markster
  14 Some OSS fixes and a few lpc changes to make it actually work
  15
  16  * Revision 1.1  1996/08/19  22:31:56  jaf
  17  * Initial revision
  18  *
  19
  20 */
  21
  22 /*  -- translated by f2c (version 19951025).
  23    You must link the resulting object file with the libraries:
  24         -lf2c -lm   (in that order)
  25 */
  26
  27 #include "f2c.h"
  28
  29 #ifdef P_R_O_T_O_T_Y_P_E_S
  30 extern int irc2pc_(real *rc, real *pc, integer *order, real *gprime, real *g2pass);
  31 #endif
  32
  33 /* ***************************************************************** */
  34
  35 /*      IRC2PC Version 48 */
  36
  37 /* $Log$
  38  * Revision 1.15  2004/06/26 03:50:14  markster
  39  * Merge source cleanups (bug #1911)
  40  *
  41  * Revision 1.14  2003/02/12 13:59:15  matteo
  42  * mer feb 12 14:56:57 CET 2003
  43  *
  44  * Revision 1.1.1.1  2003/02/12 13:59:15  matteo
  45  * mer feb 12 14:56:57 CET 2003
  46  *
  47  * Revision 1.2  2000/01/05 08:20:39  markster
  48  * Some OSS fixes and a few lpc changes to make it actually work
  49  *
  50  * Revision 1.1  1996/08/19  22:31:56  jaf
  51  * Initial revision
  52  * */
  53 /* Revision 1.3  1996/03/20  15:47:19  jaf */
  54 /* Added comments about which indices of array arguments are read or */
  55 /* written. */
  56
  57 /* Revision 1.2  1996/03/14  16:59:04  jaf */
  58 /* Comments added explaining that none of the local variables of this */
  59 /* subroutine need to be saved from one invocation to the next. */
  60
  61 /* Revision 1.1  1996/02/07 14:47:27  jaf */
  62 /* Initial revision */
  63
  64
  65 /* ***************************************************************** */
  66
  67 /*   Convert Reflection Coefficients to Predictor Coeficients */
  68
  69 /* Inputs: */
  70 /*  RC     - Reflection coefficients */
  71 /*           Indices 1 through ORDER read. */
  72 /*  ORDER  - Number of RC's */
  73 /*  GPRIME - Excitation modification gain */
  74 /* Outputs: */
  75 /*  PC     - Predictor coefficients */
  76 /*           Indices 1 through ORDER written. */
  77 /*           Indices 1 through ORDER-1 are read after being written. */
  78 /*  G2PASS - Excitation modification sharpening factor */
  79
  80 /* This subroutine has no local state. */
  81
  82 /* Subroutine */ int irc2pc_(real *rc, real *pc, integer *order, real *gprime,
  83          real *g2pass)
  84 {
  85     /* System generated locals */
  86     integer i__1, i__2;
  87
  88     /* Builtin functions */
  89     double sqrt(doublereal);
  90
  91     /* Local variables */
  92     real temp[10];
  93     integer i__, j;
  94
  95 /*      Arguments */
  96 /* $Log$
  97  * Revision 1.15  2004/06/26 03:50:14  markster
  98  * Merge source cleanups (bug #1911)
  99  *
 100  * Revision 1.14  2003/02/12 13:59:15  matteo
 101  * mer feb 12 14:56:57 CET 2003
 102  *
 103  * Revision 1.1.1.1  2003/02/12 13:59:15  matteo
 104  * mer feb 12 14:56:57 CET 2003
 105  *
 106  * Revision 1.2  2000/01/05 08:20:39  markster
 107  * Some OSS fixes and a few lpc changes to make it actually work
 108  *
 109  * Revision 1.1  1996/08/19  22:31:56  jaf
 110  * Initial revision
 111  * */
 112 /* Revision 1.3  1996/03/29  22:03:47  jaf */
 113 /* Removed definitions for any constants that were no longer used. */
 114
 115 /* Revision 1.2  1996/03/26  19:34:33  jaf */
 116 /* Added comments indicating which constants are not needed in an */
 117 /* application that uses the LPC-10 coder. */
 118
 119 /* Revision 1.1  1996/02/07  14:43:51  jaf */
 120 /* Initial revision */
 121
 122 /*   LPC Configuration parameters: */
 123 /* Frame size, Prediction order, Pitch period */
 124 /*       Local variables that need not be saved */
 125     /* Parameter adjustments */
 126     --pc;
 127     --rc;
 128
 129     /* Function Body */
 130     *g2pass = 1.f;
 131     i__1 = *order;
 132     for (i__ = 1; i__ <= i__1; ++i__) {
 133         *g2pass *= 1.f - rc[i__] * rc[i__];
 134     }
 135     *g2pass = *gprime * (real)sqrt(*g2pass);
 136     pc[1] = rc[1];
 137     i__1 = *order;
 138     for (i__ = 2; i__ <= i__1; ++i__) {
 139         i__2 = i__ - 1;
 140         for (j = 1; j <= i__2; ++j) {
 141             temp[j - 1] = pc[j] - rc[i__] * pc[i__ - j];
 142         }
 143         i__2 = i__ - 1;
 144         for (j = 1; j <= i__2; ++j) {
 145             pc[j] = temp[j - 1];
 146         }
 147         pc[i__] = rc[i__];
 148     }
 149     return 0;
 150 } /* irc2pc_ */
 151