1 files changed, 158 insertions, 0 deletions
diff --git a/codecs/ilbc/LPCdecode.c b/codecs/ilbc/LPCdecode.c
new file mode 100644
index 000000000..81bab9048
--- /dev/null
+++ b/codecs/ilbc/LPCdecode.c
@@ -0,0 +1,158 @@
+
+   /******************************************************************
+
+       iLBC Speech Coder ANSI-C Source Code
+
+       LPC_decode.c
+
+       Copyright (C) The Internet Society (2004).
+       All Rights Reserved.
+
+   ******************************************************************/
+
+   #include <math.h>
+   #include <string.h>
+
+   #include "helpfun.h"
+   #include "lsf.h"
+   #include "iLBC_define.h"
+   #include "constants.h"
+
+   /*---------------------------------------------------------------*
+    *  interpolation of lsf coefficients for the decoder
+    *--------------------------------------------------------------*/
+
+   void LSFinterpolate2a_dec(
+       float *a,           /* (o) lpc coefficients for a sub-frame */
+       float *lsf1,    /* (i) first lsf coefficient vector */
+       float *lsf2,    /* (i) second lsf coefficient vector */
+       float coef,         /* (i) interpolation weight */
+       int length          /* (i) length of lsf vectors */
+   ){
+       float  lsftmp[LPC_FILTERORDER];
+
+       interpolate(lsftmp, lsf1, lsf2, coef, length);
+       lsf2a(a, lsftmp);
+   }
+
+   /*---------------------------------------------------------------*
+    *  obtain dequantized lsf coefficients from quantization index
+    *--------------------------------------------------------------*/
+
+   void SimplelsfDEQ(
+       float *lsfdeq,    /* (o) dequantized lsf coefficients */
+       int *index,         /* (i) quantization index */
+       int lpc_n           /* (i) number of LPCs */
+   ){
+       int i, j, pos, cb_pos;
+
+
+
+
+
+       /* decode first LSF */
+
+       pos = 0;
+       cb_pos = 0;
+       for (i = 0; i < LSF_NSPLIT; i++) {
+           for (j = 0; j < dim_lsfCbTbl[i]; j++) {
+               lsfdeq[pos + j] = lsfCbTbl[cb_pos +
+                   (long)(index[i])*dim_lsfCbTbl[i] + j];
+           }
+           pos += dim_lsfCbTbl[i];
+           cb_pos += size_lsfCbTbl[i]*dim_lsfCbTbl[i];
+       }
+
+       if (lpc_n>1) {
+
+           /* decode last LSF */
+
+           pos = 0;
+           cb_pos = 0;
+           for (i = 0; i < LSF_NSPLIT; i++) {
+               for (j = 0; j < dim_lsfCbTbl[i]; j++) {
+                   lsfdeq[LPC_FILTERORDER + pos + j] =
+                       lsfCbTbl[cb_pos +
+                       (long)(index[LSF_NSPLIT + i])*
+                       dim_lsfCbTbl[i] + j];
+               }
+               pos += dim_lsfCbTbl[i];
+               cb_pos += size_lsfCbTbl[i]*dim_lsfCbTbl[i];
+           }
+       }
+   }
+
+   /*----------------------------------------------------------------*
+    *  obtain synthesis and weighting filters form lsf coefficients
+    *---------------------------------------------------------------*/
+
+   void DecoderInterpolateLSF(
+       float *syntdenum, /* (o) synthesis filter coefficients */
+       float *weightdenum, /* (o) weighting denumerator
+                                  coefficients */
+       float *lsfdeq,       /* (i) dequantized lsf coefficients */
+       int length,         /* (i) length of lsf coefficient vector */
+       iLBC_Dec_Inst_t *iLBCdec_inst
+                           /* (i) the decoder state structure */
+   ){
+       int    i, pos, lp_length;
+       float  lp[LPC_FILTERORDER + 1], *lsfdeq2;
+
+
+
+
+
+
+       lsfdeq2 = lsfdeq + length;
+       lp_length = length + 1;
+
+       if (iLBCdec_inst->mode==30) {
+           /* sub-frame 1: Interpolation between old and first */
+
+           LSFinterpolate2a_dec(lp, iLBCdec_inst->lsfdeqold, lsfdeq,
+               lsf_weightTbl_30ms[0], length);
+           memcpy(syntdenum,lp,lp_length*sizeof(float));
+           bwexpand(weightdenum, lp, LPC_CHIRP_WEIGHTDENUM,
+               lp_length);
+
+           /* sub-frames 2 to 6: interpolation between first
+              and last LSF */
+
+           pos = lp_length;
+           for (i = 1; i < 6; i++) {
+               LSFinterpolate2a_dec(lp, lsfdeq, lsfdeq2,
+                   lsf_weightTbl_30ms[i], length);
+               memcpy(syntdenum + pos,lp,lp_length*sizeof(float));
+               bwexpand(weightdenum + pos, lp,
+                   LPC_CHIRP_WEIGHTDENUM, lp_length);
+               pos += lp_length;
+           }
+       }
+       else {
+           pos = 0;
+           for (i = 0; i < iLBCdec_inst->nsub; i++) {
+               LSFinterpolate2a_dec(lp, iLBCdec_inst->lsfdeqold,
+                   lsfdeq, lsf_weightTbl_20ms[i], length);
+               memcpy(syntdenum+pos,lp,lp_length*sizeof(float));
+               bwexpand(weightdenum+pos, lp, LPC_CHIRP_WEIGHTDENUM,
+                   lp_length);
+               pos += lp_length;
+           }
+       }
+
+       /* update memory */
+
+       if (iLBCdec_inst->mode==30)
+           memcpy(iLBCdec_inst->lsfdeqold, lsfdeq2,
+                       length*sizeof(float));
+       else
+           memcpy(iLBCdec_inst->lsfdeqold, lsfdeq,
+                       length*sizeof(float));
+
+   }
+
+
+
+
+
+