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