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 "modules/audio_coding/codecs/ilbc/bw_expand.h"
20
21 #include "modules/audio_coding/codecs/ilbc/defines.h"
22
23 /*----------------------------------------------------------------*
24 * lpc bandwidth expansion
25 *---------------------------------------------------------------*/
26
27 /* The output is in the same domain as the input */
WebRtcIlbcfix_BwExpand(int16_t * out,int16_t * in,int16_t * coef,int16_t length)28 void WebRtcIlbcfix_BwExpand(
29 int16_t *out, /* (o) the bandwidth expanded lpc coefficients */
30 int16_t *in, /* (i) the lpc coefficients before bandwidth
31 expansion */
32 int16_t *coef, /* (i) the bandwidth expansion factor Q15 */
33 int16_t length /* (i) the length of lpc coefficient vectors */
34 ) {
35 int i;
36
37 out[0] = in[0];
38 for (i = 1; i < length; i++) {
39 /* out[i] = coef[i] * in[i] with rounding.
40 in[] and out[] are in Q12 and coef[] is in Q15
41 */
42 out[i] = (int16_t)((coef[i] * in[i] + 16384) >> 15);
43 }
44 }
45