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_LpcEncode.c
16
17 ******************************************************************/
18
19 #include "defines.h"
20 #include "simple_lpc_analysis.h"
21 #include "simple_interpolate_lsf.h"
22 #include "simple_lsf_quant.h"
23 #include "lsf_check.h"
24 #include "constants.h"
25
26 /*----------------------------------------------------------------*
27 * lpc encoder
28 *---------------------------------------------------------------*/
29
WebRtcIlbcfix_LpcEncode(int16_t * syntdenum,int16_t * weightdenum,int16_t * lsf_index,int16_t * data,IlbcEncoder * iLBCenc_inst)30 void WebRtcIlbcfix_LpcEncode(
31 int16_t *syntdenum, /* (i/o) synthesis filter coefficients
32 before/after encoding */
33 int16_t *weightdenum, /* (i/o) weighting denumerator coefficients
34 before/after encoding */
35 int16_t *lsf_index, /* (o) lsf quantization index */
36 int16_t *data, /* (i) Speech to do LPC analysis on */
37 IlbcEncoder *iLBCenc_inst
38 /* (i/o) the encoder state structure */
39 ) {
40 /* Stack based */
41 int16_t lsf[LPC_FILTERORDER * LPC_N_MAX];
42 int16_t lsfdeq[LPC_FILTERORDER * LPC_N_MAX];
43
44 /* Calculate LSF's from the input speech */
45 WebRtcIlbcfix_SimpleLpcAnalysis(lsf, data, iLBCenc_inst);
46
47 /* Quantize the LSF's */
48 WebRtcIlbcfix_SimpleLsfQ(lsfdeq, lsf_index, lsf, iLBCenc_inst->lpc_n);
49
50 /* Stableize the LSF's if needed */
51 WebRtcIlbcfix_LsfCheck(lsfdeq, LPC_FILTERORDER, iLBCenc_inst->lpc_n);
52
53 /* Calculate the synthesis and weighting filter coefficients from
54 the optimal LSF and the dequantized LSF */
55 WebRtcIlbcfix_SimpleInterpolateLsf(syntdenum, weightdenum,
56 lsf, lsfdeq, iLBCenc_inst->lsfold,
57 iLBCenc_inst->lsfdeqold, LPC_FILTERORDER, iLBCenc_inst);
58
59 return;
60 }
61