--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/intercom/ilbc/FrameClassify.c	Fri Jun 25 09:57:52 2010 +0200
@@ -0,0 +1,117 @@
+
+   /******************************************************************
+
+       iLBC Speech Coder ANSI-C Source Code
+
+       FrameClassify.c
+
+       Copyright (C) The Internet Society (2004).
+       All Rights Reserved.
+
+   ******************************************************************/
+
+#include "iLBC_define.h"
+
+   /*---------------------------------------------------------------*
+    *  Classification of subframes to localize start state
+    *--------------------------------------------------------------*/
+
+int FrameClassify(              /* index to the max-energy sub-frame */
+  iLBC_Enc_Inst_t * iLBCenc_inst,
+  /* (i/o) the encoder state structure */
+  float *residual               /* (i) lpc residual signal */
+  )
+{
+  float max_ssqEn, fssqEn[NSUB_MAX], bssqEn[NSUB_MAX], *pp;
+  int n, l, max_ssqEn_n;
+  const float ssqEn_win[NSUB_MAX - 1] = { (float) 0.8, (float) 0.9,
+    (float) 1.0, (float) 0.9, (float) 0.8
+  };
+  const float sampEn_win[5] = { (float) 1.0 / (float) 6.0,
+    (float) 2.0 / (float) 6.0, (float) 3.0 / (float) 6.0,
+    (float) 4.0 / (float) 6.0, (float) 5.0 / (float) 6.0
+  };
+
+  /* init the front and back energies to zero */
+
+  memset(fssqEn, 0, NSUB_MAX * sizeof(float));
+  memset(bssqEn, 0, NSUB_MAX * sizeof(float));
+
+  /* Calculate front of first seqence */
+
+  n = 0;
+  pp = residual;
+  for (l = 0; l < 5; l++) {
+    fssqEn[n] += sampEn_win[l] * (*pp) * (*pp);
+    pp++;
+  }
+  for (l = 5; l < SUBL; l++) {
+
+
+
+
+
+    fssqEn[n] += (*pp) * (*pp);
+    pp++;
+  }
+
+  /* Calculate front and back of all middle sequences */
+
+  for (n = 1; n < iLBCenc_inst->nsub - 1; n++) {
+    pp = residual + n * SUBL;
+    for (l = 0; l < 5; l++) {
+      fssqEn[n] += sampEn_win[l] * (*pp) * (*pp);
+      bssqEn[n] += (*pp) * (*pp);
+      pp++;
+    }
+    for (l = 5; l < SUBL - 5; l++) {
+      fssqEn[n] += (*pp) * (*pp);
+      bssqEn[n] += (*pp) * (*pp);
+      pp++;
+    }
+    for (l = SUBL - 5; l < SUBL; l++) {
+      fssqEn[n] += (*pp) * (*pp);
+      bssqEn[n] += sampEn_win[SUBL - l - 1] * (*pp) * (*pp);
+      pp++;
+    }
+  }
+
+  /* Calculate back of last seqence */
+
+  n = iLBCenc_inst->nsub - 1;
+  pp = residual + n * SUBL;
+  for (l = 0; l < SUBL - 5; l++) {
+    bssqEn[n] += (*pp) * (*pp);
+    pp++;
+  }
+  for (l = SUBL - 5; l < SUBL; l++) {
+    bssqEn[n] += sampEn_win[SUBL - l - 1] * (*pp) * (*pp);
+    pp++;
+  }
+
+  /* find the index to the weighted 80 sample with
+     most energy */
+
+  if (iLBCenc_inst->mode == 20)
+    l = 1;
+  else
+    l = 0;
+
+  max_ssqEn = (fssqEn[0] + bssqEn[1]) * ssqEn_win[l];
+  max_ssqEn_n = 1;
+  for (n = 2; n < iLBCenc_inst->nsub; n++) {
+
+
+
+
+
+
+    l++;
+    if ((fssqEn[n - 1] + bssqEn[n]) * ssqEn_win[l] > max_ssqEn) {
+      max_ssqEn = (fssqEn[n - 1] + bssqEn[n]) * ssqEn_win[l];
+      max_ssqEn_n = n;
+    }
+  }
+
+  return max_ssqEn_n;
+}