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 */ 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)((WEBRTC_SPL_MUL_16_16(coef[i], in[i])+16384)>>15); 41 } 42 } 43
