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_BwExpand.c
16 
17 ******************************************************************/
18 
19 #include "defines.h"
20 
21 /*----------------------------------------------------------------*
22  *  lpc bandwidth expansion
23  *---------------------------------------------------------------*/
24 
25 /* The output is in the same domain as the input */
WebRtcIlbcfix_BwExpand(int16_t * out,int16_t * in,int16_t * coef,int16_t length)26 void WebRtcIlbcfix_BwExpand(
27     int16_t *out, /* (o) the bandwidth expanded lpc coefficients */
28     int16_t *in,  /* (i) the lpc coefficients before bandwidth
29                                    expansion */
30     int16_t *coef, /* (i) the bandwidth expansion factor Q15 */
31     int16_t length /* (i) the length of lpc coefficient vectors */
32                             ) {
33   int i;
34 
35   out[0] = in[0];
36   for (i = 1; i < length; i++) {
37     /* out[i] = coef[i] * in[i] with rounding.
38        in[] and out[] are in Q12 and coef[] is in Q15
39     */
40     out[i] = (int16_t)((coef[i] * in[i] + 16384) >> 15);
41   }
42 }
43