Add iLBC codec

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@852 65c4cc65-6c06-0410-ace0-fbb531ad65f3

codecs/ilbc/StateConstructW.c

@@ -0,0 +1,72 @@
+ 
+/****************************************************************** 
+ 
+    iLBC Speech Coder ANSI-C Source Code 
+ 
+    StateConstructW.c  
+ 
+    Copyright (c) 2001, 
+    Global IP Sound AB. 
+    All rights reserved. 
+ 
+******************************************************************/ 
+ 
+#include <math.h>  
+#include <string.h> 
+ 
+#include "iLBC_define.h" 
+#include "constants.h" 
+#include "filter.h" 
+ 
+/*----------------------------------------------------------------* 
+ *  decoding of the start state 
+ *---------------------------------------------------------------*/ 
+ 
+void StateConstructW(  
+    int idxForMax,      /* (i) 6-bit index for the quantization of  
+                               max amplitude */ 
+    int *idxVec,    /* (i) vector of quantization indexes */ 
+    float *syntDenum,   /* (i) synthesis filter denumerator */ 
+    float *out,         /* (o) the decoded state vector */ 
+    int len             /* (i) length of a state vector */ 
+){ 
+    float maxVal, tmpbuf[LPC_FILTERORDER+2*STATE_LEN], *tmp,  
+        numerator[LPC_FILTERORDER+1]; 
+    float foutbuf[LPC_FILTERORDER+2*STATE_LEN], *fout; 
+    int k,tmpi; 
+     
+    /* decoding of the maximum value */ 
+ 
+    maxVal = state_frgqTbl[idxForMax]; 
+    maxVal = (float)pow(10,maxVal)/(float)4.5; 
+         
+    /* initialization of buffers and coefficients */ 
+     
+    memset(tmpbuf, 0, LPC_FILTERORDER*sizeof(float)); 
+    memset(foutbuf, 0, LPC_FILTERORDER*sizeof(float)); 
+    for(k=0; k<LPC_FILTERORDER; k++){ 
+        numerator[k]=syntDenum[LPC_FILTERORDER-k]; 
+    } 
+    numerator[LPC_FILTERORDER]=syntDenum[0]; 
+    tmp = &tmpbuf[LPC_FILTERORDER]; 
+    fout = &foutbuf[LPC_FILTERORDER]; 
+ 
+    /* decoding of the sample values */ 
+     
+    for(k=0; k<len; k++){ 
+        tmpi = len-1-k; 
+        /* maxVal = 1/scal */ 
+        tmp[k] = maxVal*state_sq3Tbl[idxVec[tmpi]]; 
+    } 
+ 
+    /* circular convolution with all-pass filter */ 
+ 
+    memset(tmp+len, 0, len*sizeof(float)); 
+    ZeroPoleFilter(tmp, numerator, syntDenum, 2*len,  
+        LPC_FILTERORDER, fout); 
+    for(k=0;k<len;k++){ 
+        out[k] = fout[len-1-k]+fout[2*len-1-k]; 
+    } 
+} 
+ 
+