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_InterpolateSamples.c 16 17 ******************************************************************/ 18 19 #include "modules/audio_coding/codecs/ilbc/interpolate_samples.h" 20 21 #include "modules/audio_coding/codecs/ilbc/constants.h" 22 #include "modules/audio_coding/codecs/ilbc/defines.h" 23 WebRtcIlbcfix_InterpolateSamples(int16_t * interpSamples,int16_t * CBmem,size_t lMem)24void WebRtcIlbcfix_InterpolateSamples( 25 int16_t *interpSamples, /* (o) The interpolated samples */ 26 int16_t *CBmem, /* (i) The CB memory */ 27 size_t lMem /* (i) Length of the CB memory */ 28 ) { 29 int16_t *ppi, *ppo, i, j, temp1, temp2; 30 int16_t *tmpPtr; 31 32 /* Calculate the 20 vectors of interpolated samples (4 samples each) 33 that are used in the codebooks for lag 20 to 39 */ 34 tmpPtr = interpSamples; 35 for (j=0; j<20; j++) { 36 temp1 = 0; 37 temp2 = 3; 38 ppo = CBmem+lMem-4; 39 ppi = CBmem+lMem-j-24; 40 for (i=0; i<4; i++) { 41 42 *tmpPtr++ = (int16_t)((WebRtcIlbcfix_kAlpha[temp2] * *ppo) >> 15) + 43 (int16_t)((WebRtcIlbcfix_kAlpha[temp1] * *ppi) >> 15); 44 45 ppo++; 46 ppi++; 47 temp1++; 48 temp2--; 49 } 50 } 51 52 return; 53 } 54