modules/audio_coding/codecs/ilbc/lsf_interpolate_to_poly_dec.c

/*
 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

/******************************************************************

 iLBC Speech Coder ANSI-C Source Code

 WebRtcIlbcfix_LspInterpolate2PolyDec.c

******************************************************************/

#include "modules/audio_coding/codecs/ilbc/lsf_interpolate_to_poly_dec.h"

#include "modules/audio_coding/codecs/ilbc/defines.h"
#include "modules/audio_coding/codecs/ilbc/interpolate.h"
#include "modules/audio_coding/codecs/ilbc/lsf_to_poly.h"

/*----------------------------------------------------------------*
 *  interpolation of lsf coefficients for the decoder
 *---------------------------------------------------------------*/

void WebRtcIlbcfix_LspInterpolate2PolyDec(
    int16_t *a,   /* (o) lpc coefficients Q12 */
    int16_t *lsf1,  /* (i) first set of lsf coefficients Q13 */
    int16_t *lsf2,  /* (i) second set of lsf coefficients Q13 */
    int16_t coef,  /* (i) weighting coefficient to use between
                                   lsf1 and lsf2 Q14 */
    int16_t length  /* (i) length of coefficient vectors */
                                          ){
  int16_t lsftmp[LPC_FILTERORDER];

  /* interpolate LSF */
  WebRtcIlbcfix_Interpolate(lsftmp, lsf1, lsf2, coef, length);

  /* Compute the filter coefficients from the LSF */
  WebRtcIlbcfix_Lsf2Poly(a, lsftmp);
}