Add iLBC codec

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

1 files changed, 65 insertions, 0 deletions

diff --git a/codecs/ilbc/syntFilter.c b/codecs/ilbc/syntFilter.c
new file mode 100755
index 000000000..fe61eaa46
--- /dev/null
+++ b/codecs/ilbc/syntFilter.c
@@ -0,0 +1,65 @@
+ 
+/****************************************************************** 
+ 
+    iLBC Speech Coder ANSI-C Source Code 
+ 
+    syntFilter.c  
+ 
+    Copyright (c) 2001, 
+    Global IP Sound AB. 
+    All rights reserved. 
+ 
+******************************************************************/ 
+ 
+#include "iLBC_define.h" 
+ 
+/*----------------------------------------------------------------* 
+ *  LP synthesis filter. 
+ *---------------------------------------------------------------*/ 
+     
+void syntFilter( 
+    float *Out,     /* (i/o) Signal to be filtered */ 
+    float *a,       /* (i) LP parameters */ 
+    int len,    /* (i) Length of signal */ 
+    float *mem      /* (i/o) Filter state */ 
+){ 
+    int i, j; 
+    float *po, *pi, *pa, *pm; 
+ 
+    po=Out; 
+ 
+    /* Filter first part using memory from past */ 
+ 
+    for (i=0;i<LPC_FILTERORDER;i++) { 
+        pi=&Out[i-1]; 
+        pa=&a[1]; 
+        pm=&mem[LPC_FILTERORDER-1]; 
+        for (j=1;j<=i;j++) { 
+            *po-=(*pa++)*(*pi--); 
+        } 
+        for (j=i+1;j<LPC_FILTERORDER+1;j++) { 
+            *po-=(*pa++)*(*pm--); 
+        } 
+        po++; 
+    } 
+ 
+    /* Filter last part where the state is entierly in  
+       the output vector */ 
+     
+    for (i=LPC_FILTERORDER;i<len;i++) { 
+        pi=&Out[i-1]; 
+        pa=&a[1]; 
+        for (j=1;j<LPC_FILTERORDER+1;j++) { 
+            *po-=(*pa++)*(*pi--); 
+        } 
+        po++; 
+    } 
+ 
+    /* Update state vector */ 
+ 
+    memcpy(mem, &Out[len-LPC_FILTERORDER],  
+        LPC_FILTERORDER*sizeof(float)); 
+} 
+ 
+ 
+