1 files changed, 116 insertions, 0 deletions
diff --git a/codecs/ilbc/gainquant.c b/codecs/ilbc/gainquant.c
new file mode 100644
index 000000000..0e74ff827
--- /dev/null
+++ b/codecs/ilbc/gainquant.c
@@ -0,0 +1,116 @@
+
+   /******************************************************************
+
+       iLBC Speech Coder ANSI-C Source Code
+
+
+
+
+
+
+       gainquant.c
+
+       Copyright (C) The Internet Society (2004).
+       All Rights Reserved.
+
+   ******************************************************************/
+
+   #include <string.h>
+   #include <math.h>
+   #include "constants.h"
+   #include "filter.h"
+
+   /*----------------------------------------------------------------*
+    *  quantizer for the gain in the gain-shape coding of residual
+    *---------------------------------------------------------------*/
+
+   float gainquant(/* (o) quantized gain value */
+       float in,       /* (i) gain value */
+       float maxIn,/* (i) maximum of gain value */
+       int cblen,      /* (i) number of quantization indices */
+       int *index      /* (o) quantization index */
+   ){
+       int i, tindex;
+       float minmeasure,measure, *cb, scale;
+
+       /* ensure a lower bound on the scaling factor */
+
+       scale=maxIn;
+
+       if (scale<0.1) {
+           scale=(float)0.1;
+       }
+
+       /* select the quantization table */
+
+       if (cblen == 8) {
+           cb = gain_sq3Tbl;
+       } else if (cblen == 16) {
+           cb = gain_sq4Tbl;
+       } else  {
+           cb = gain_sq5Tbl;
+       }
+
+       /* select the best index in the quantization table */
+
+       minmeasure=10000000.0;
+       tindex=0;
+       for (i=0; i<cblen; i++) {
+
+
+
+
+
+           measure=(in-scale*cb[i])*(in-scale*cb[i]);
+
+           if (measure<minmeasure) {
+               tindex=i;
+               minmeasure=measure;
+           }
+       }
+       *index=tindex;
+
+       /* return the quantized value */
+
+       return scale*cb[tindex];
+   }
+
+   /*----------------------------------------------------------------*
+    *  decoder for quantized gains in the gain-shape coding of
+    *  residual
+    *---------------------------------------------------------------*/
+
+   float gaindequant(  /* (o) quantized gain value */
+       int index,      /* (i) quantization index */
+       float maxIn,/* (i) maximum of unquantized gain */
+       int cblen       /* (i) number of quantization indices */
+   ){
+       float scale;
+
+       /* obtain correct scale factor */
+
+       scale=(float)fabs(maxIn);
+
+       if (scale<0.1) {
+           scale=(float)0.1;
+       }
+
+       /* select the quantization table and return the decoded value */
+
+       if (cblen==8) {
+           return scale*gain_sq3Tbl[index];
+       } else if (cblen==16) {
+           return scale*gain_sq4Tbl[index];
+       }
+       else if (cblen==32) {
+           return scale*gain_sq5Tbl[index];
+       }
+
+       return 0.0;
+   }
+
+
+
+
+
+