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_SimpleLsfDeQ.c
16
17******************************************************************/
18
19#include "defines.h"
20#include "constants.h"
21
22/*----------------------------------------------------------------*
23 *  obtain dequantized lsf coefficients from quantization index
24 *---------------------------------------------------------------*/
25
26void WebRtcIlbcfix_SimpleLsfDeQ(
27    int16_t *lsfdeq,  /* (o) dequantized lsf coefficients */
28    int16_t *index,  /* (i) quantization index */
29    int16_t lpc_n  /* (i) number of LPCs */
30                                ){
31  int i, j, pos, cb_pos;
32
33  /* decode first LSF */
34
35  pos = 0;
36  cb_pos = 0;
37  for (i = 0; i < LSF_NSPLIT; i++) {
38    for (j = 0; j < WebRtcIlbcfix_kLsfDimCb[i]; j++) {
39      lsfdeq[pos + j] = WebRtcIlbcfix_kLsfCb[cb_pos + j + index[i] *
40                                             WebRtcIlbcfix_kLsfDimCb[i]];
41    }
42    pos += WebRtcIlbcfix_kLsfDimCb[i];
43    cb_pos += WebRtcIlbcfix_kLsfSizeCb[i] * WebRtcIlbcfix_kLsfDimCb[i];
44  }
45
46  if (lpc_n>1) {
47    /* decode last LSF */
48    pos = 0;
49    cb_pos = 0;
50    for (i = 0; i < LSF_NSPLIT; i++) {
51      for (j = 0; j < WebRtcIlbcfix_kLsfDimCb[i]; j++) {
52        lsfdeq[LPC_FILTERORDER + pos + j] = WebRtcIlbcfix_kLsfCb[
53            cb_pos + index[LSF_NSPLIT + i] * WebRtcIlbcfix_kLsfDimCb[i] + j];
54      }
55      pos += WebRtcIlbcfix_kLsfDimCb[i];
56      cb_pos += WebRtcIlbcfix_kLsfSizeCb[i] * WebRtcIlbcfix_kLsfDimCb[i];
57    }
58  }
59  return;
60}
61