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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 /******************************************************************
     12 
     13  iLBC Speech Coder ANSI-C Source Code
     14 
     15  WebRtcIlbcfix_LspInterpolate2PolyDec.c
     16 
     17 ******************************************************************/
     18 
     19 #include "interpolate.h"
     20 #include "lsf_to_poly.h"
     21 #include "defines.h"
     22 
     23 /*----------------------------------------------------------------*
     24  *  interpolation of lsf coefficients for the decoder
     25  *---------------------------------------------------------------*/
     26 
     27 void WebRtcIlbcfix_LspInterpolate2PolyDec(
     28     int16_t *a,   /* (o) lpc coefficients Q12 */
     29     int16_t *lsf1,  /* (i) first set of lsf coefficients Q13 */
     30     int16_t *lsf2,  /* (i) second set of lsf coefficients Q13 */
     31     int16_t coef,  /* (i) weighting coefficient to use between
     32                                    lsf1 and lsf2 Q14 */
     33     int16_t length  /* (i) length of coefficient vectors */
     34                                           ){
     35   int16_t lsftmp[LPC_FILTERORDER];
     36 
     37   /* interpolate LSF */
     38   WebRtcIlbcfix_Interpolate(lsftmp, lsf1, lsf2, coef, length);
     39 
     40   /* Compute the filter coefficients from the LSF */
     41   WebRtcIlbcfix_Lsf2Poly(a, lsftmp);
     42 }
     43