1 files changed, 80 insertions, 0 deletions
diff --git a/codecs/ilbc/syntFilter.c b/codecs/ilbc/syntFilter.c
new file mode 100644
index 000000000..190eb009d
--- /dev/null
+++ b/codecs/ilbc/syntFilter.c
@@ -0,0 +1,80 @@
+
+   /******************************************************************
+
+       iLBC Speech Coder ANSI-C Source Code
+
+       syntFilter.c
+
+       Copyright (C) The Internet Society (2004).
+       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 entirely 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));
+   }
+
+
+
+
+
+
+
+
+
+
+
+
+
+