Add iLBC codec

git-svn-id: http://svn.digium.com/svn/asterisk/trunk@852 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 100 insertions, 0 deletions

diff --git a/codecs/ilbc/FrameClassify.c b/codecs/ilbc/FrameClassify.c
new file mode 100755
index 000000000..61ede133b
--- /dev/null
+++ b/codecs/ilbc/FrameClassify.c
@@ -0,0 +1,100 @@
+ 
+/****************************************************************** 
+ 
+    iLBC Speech Coder ANSI-C Source Code 
+ 
+    FrameClassify.c  
+ 
+    Copyright (c) 2001, 
+    Global IP Sound AB. 
+    All rights reserved. 
+ 
+******************************************************************/ 
+ 
+#include "iLBC_define.h" 
+ 
+/*----------------------------------------------------------------* 
+ *  Classification of subframes to localize start state                           
+ *---------------------------------------------------------------*/ 
+ 
+int FrameClassify(  /* index to the max-energy sub frame */ 
+    float *residual /* (i) lpc residual signal */ 
+){ 
+    float max_ssqEn, fssqEn[NSUB], bssqEn[NSUB], *pp; 
+    int n, l, max_ssqEn_n; 
+    const float ssqEn_win[NSUB-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*sizeof(float)); 
+    memset(bssqEn, 0, NSUB*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<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=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 */ 
+ 
+    max_ssqEn=(fssqEn[0]+bssqEn[1])*ssqEn_win[0]; 
+    max_ssqEn_n=1; 
+    for (n=2;n<NSUB;n++) { 
+         
+        if ((fssqEn[n-1]+bssqEn[n])*ssqEn_win[n-1] > max_ssqEn) { 
+            max_ssqEn=(fssqEn[n-1]+bssqEn[n]) * 
+                            ssqEn_win[n-1]; 
+            max_ssqEn_n=n; 
+        } 
+    } 
+ 
+    return max_ssqEn_n; 
+} 
+ 
+