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 "modules/audio_coding/codecs/ilbc/interpolate.h" 20 21 #include "modules/audio_coding/codecs/ilbc/constants.h" 22 #include "modules/audio_coding/codecs/ilbc/defines.h" 23 24 /*----------------------------------------------------------------* 25 * interpolation between vectors 26 *---------------------------------------------------------------*/ 27 WebRtcIlbcfix_Interpolate(int16_t * out,int16_t * in1,int16_t * in2,int16_t coef,int16_t length)28void WebRtcIlbcfix_Interpolate( 29 int16_t *out, /* (o) output vector */ 30 int16_t *in1, /* (i) first input vector */ 31 int16_t *in2, /* (i) second input vector */ 32 int16_t coef, /* (i) weight coefficient in Q14 */ 33 int16_t length) /* (i) number of sample is vectors */ 34 { 35 int i; 36 int16_t invcoef; 37 38 /* 39 Performs the operation out[i] = in[i]*coef + (1-coef)*in2[i] (with rounding) 40 */ 41 42 invcoef = 16384 - coef; /* 16384 = 1.0 (Q14)*/ 43 for (i = 0; i < length; i++) { 44 out[i] = (int16_t)((coef * in1[i] + invcoef * in2[i] + 8192) >> 14); 45 } 46 47 return; 48 } 49