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_Interpolate.c
16
17 ******************************************************************/
18
19 #include "defines.h"
20 #include "constants.h"
21
22 /*----------------------------------------------------------------*
23 * interpolation between vectors
24 *---------------------------------------------------------------*/
25
WebRtcIlbcfix_Interpolate(int16_t * out,int16_t * in1,int16_t * in2,int16_t coef,int16_t length)26 void WebRtcIlbcfix_Interpolate(
27 int16_t *out, /* (o) output vector */
28 int16_t *in1, /* (i) first input vector */
29 int16_t *in2, /* (i) second input vector */
30 int16_t coef, /* (i) weight coefficient in Q14 */
31 int16_t length) /* (i) number of sample is vectors */
32 {
33 int i;
34 int16_t invcoef;
35
36 /*
37 Performs the operation out[i] = in[i]*coef + (1-coef)*in2[i] (with rounding)
38 */
39
40 invcoef = 16384 - coef; /* 16384 = 1.0 (Q14)*/
41 for (i = 0; i < length; i++) {
42 out[i] = (int16_t)((coef * in1[i] + invcoef * in2[i] + 8192) >> 14);
43 }
44
45 return;
46 }
47