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_StateConstruct.c
16
17 ******************************************************************/
18
19 #include "modules/audio_coding/codecs/ilbc/defines.h"
20 #include "modules/audio_coding/codecs/ilbc/constants.h"
21
22 /*----------------------------------------------------------------*
23 * decoding of the start state
24 *---------------------------------------------------------------*/
25
WebRtcIlbcfix_StateConstruct(size_t idxForMax,int16_t * idxVec,int16_t * syntDenum,int16_t * Out_fix,size_t len)26 void WebRtcIlbcfix_StateConstruct(
27 size_t idxForMax, /* (i) 6-bit index for the quantization of
28 max amplitude */
29 int16_t *idxVec, /* (i) vector of quantization indexes */
30 int16_t *syntDenum, /* (i) synthesis filter denumerator */
31 int16_t *Out_fix, /* (o) the decoded state vector */
32 size_t len /* (i) length of a state vector */
33 ) {
34 size_t k;
35 int16_t maxVal;
36 int16_t *tmp1, *tmp2, *tmp3;
37 /* Stack based */
38 int16_t numerator[1+LPC_FILTERORDER];
39 int16_t sampleValVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
40 int16_t sampleMaVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
41 int16_t *sampleVal = &sampleValVec[LPC_FILTERORDER];
42 int16_t *sampleMa = &sampleMaVec[LPC_FILTERORDER];
43 int16_t *sampleAr = &sampleValVec[LPC_FILTERORDER];
44
45 /* initialization of coefficients */
46
47 for (k=0; k<LPC_FILTERORDER+1; k++){
48 numerator[k] = syntDenum[LPC_FILTERORDER-k];
49 }
50
51 /* decoding of the maximum value */
52
53 maxVal = WebRtcIlbcfix_kFrgQuantMod[idxForMax];
54
55 /* decoding of the sample values */
56 tmp1 = sampleVal;
57 tmp2 = &idxVec[len-1];
58
59 if (idxForMax<37) {
60 for(k=0; k<len; k++){
61 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 2097152 (= 0.5 << 22)
62 maxVal is in Q8 and result is in Q(-1) */
63 *tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 2097152) >>
64 22);
65 tmp1++;
66 tmp2--;
67 }
68 } else if (idxForMax<59) {
69 for(k=0; k<len; k++){
70 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 262144 (= 0.5 << 19)
71 maxVal is in Q5 and result is in Q(-1) */
72 *tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 262144) >>
73 19);
74 tmp1++;
75 tmp2--;
76 }
77 } else {
78 for(k=0; k<len; k++){
79 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 65536 (= 0.5 << 17)
80 maxVal is in Q3 and result is in Q(-1) */
81 *tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 65536) >>
82 17);
83 tmp1++;
84 tmp2--;
85 }
86 }
87
88 /* Set the rest of the data to zero */
89 WebRtcSpl_MemSetW16(&sampleVal[len], 0, len);
90
91 /* circular convolution with all-pass filter */
92
93 /* Set the state to zero */
94 WebRtcSpl_MemSetW16(sampleValVec, 0, (LPC_FILTERORDER));
95
96 /* Run MA filter + AR filter */
97 WebRtcSpl_FilterMAFastQ12(
98 sampleVal, sampleMa,
99 numerator, LPC_FILTERORDER+1, len + LPC_FILTERORDER);
100 WebRtcSpl_MemSetW16(&sampleMa[len + LPC_FILTERORDER], 0, (len - LPC_FILTERORDER));
101 WebRtcSpl_FilterARFastQ12(
102 sampleMa, sampleAr,
103 syntDenum, LPC_FILTERORDER+1, 2 * len);
104
105 tmp1 = &sampleAr[len-1];
106 tmp2 = &sampleAr[2*len-1];
107 tmp3 = Out_fix;
108 for(k=0;k<len;k++){
109 (*tmp3) = (*tmp1) + (*tmp2);
110 tmp1--;
111 tmp2--;
112 tmp3++;
113 }
114 }
115