1 files changed, 110 insertions, 0 deletions
diff --git a/trunk/codecs/ilbc/FrameClassify.c b/trunk/codecs/ilbc/FrameClassify.c
new file mode 100644
index 000000000..c982fd667
--- /dev/null
+++ b/trunk/codecs/ilbc/FrameClassify.c
@@ -0,0 +1,110 @@
+
+/******************************************************************
+
+    iLBC Speech Coder ANSI-C Source Code
+
+    FrameClassify.c 
+
+    Copyright (C) The Internet Society (2004). 
+    All Rights Reserved.
+
+******************************************************************/
+
+#include "iLBC_define.h"
+#include "FrameClassify.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;
+}
+
+