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/state_construct.h"
20
21 #include "modules/audio_coding/codecs/ilbc/constants.h"
22 #include "modules/audio_coding/codecs/ilbc/defines.h"
23
24 /*----------------------------------------------------------------*
25 * decoding of the start state
26 *---------------------------------------------------------------*/
27
WebRtcIlbcfix_StateConstruct(size_t idxForMax,int16_t * idxVec,int16_t * syntDenum,int16_t * Out_fix,size_t len)28 void WebRtcIlbcfix_StateConstruct(
29 size_t idxForMax, /* (i) 6-bit index for the quantization of
30 max amplitude */
31 int16_t *idxVec, /* (i) vector of quantization indexes */
32 int16_t *syntDenum, /* (i) synthesis filter denumerator */
33 int16_t *Out_fix, /* (o) the decoded state vector */
34 size_t len /* (i) length of a state vector */
35 ) {
36 size_t k;
37 int16_t maxVal;
38 int16_t *tmp1, *tmp2, *tmp3;
39 /* Stack based */
40 int16_t numerator[1+LPC_FILTERORDER];
41 int16_t sampleValVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
42 int16_t sampleMaVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
43 int16_t *sampleVal = &sampleValVec[LPC_FILTERORDER];
44 int16_t *sampleMa = &sampleMaVec[LPC_FILTERORDER];
45 int16_t *sampleAr = &sampleValVec[LPC_FILTERORDER];
46
47 /* initialization of coefficients */
48
49 for (k=0; k<LPC_FILTERORDER+1; k++){
50 numerator[k] = syntDenum[LPC_FILTERORDER-k];
51 }
52
53 /* decoding of the maximum value */
54
55 maxVal = WebRtcIlbcfix_kFrgQuantMod[idxForMax];
56
57 /* decoding of the sample values */
58 tmp1 = sampleVal;
59 tmp2 = &idxVec[len-1];
60
61 if (idxForMax<37) {
62 for(k=0; k<len; k++){
63 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 2097152 (= 0.5 << 22)
64 maxVal is in Q8 and result is in Q(-1) */
65 *tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 2097152) >>
66 22);
67 tmp1++;
68 tmp2--;
69 }
70 } else if (idxForMax<59) {
71 for(k=0; k<len; k++){
72 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 262144 (= 0.5 << 19)
73 maxVal is in Q5 and result is in Q(-1) */
74 *tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 262144) >>
75 19);
76 tmp1++;
77 tmp2--;
78 }
79 } else {
80 for(k=0; k<len; k++){
81 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 65536 (= 0.5 << 17)
82 maxVal is in Q3 and result is in Q(-1) */
83 *tmp1 = (int16_t)((maxVal * WebRtcIlbcfix_kStateSq3[*tmp2] + 65536) >>
84 17);
85 tmp1++;
86 tmp2--;
87 }
88 }
89
90 /* Set the rest of the data to zero */
91 WebRtcSpl_MemSetW16(&sampleVal[len], 0, len);
92
93 /* circular convolution with all-pass filter */
94
95 /* Set the state to zero */
96 WebRtcSpl_MemSetW16(sampleValVec, 0, (LPC_FILTERORDER));
97
98 /* Run MA filter + AR filter */
99 WebRtcSpl_FilterMAFastQ12(
100 sampleVal, sampleMa,
101 numerator, LPC_FILTERORDER+1, len + LPC_FILTERORDER);
102 WebRtcSpl_MemSetW16(&sampleMa[len + LPC_FILTERORDER], 0, (len - LPC_FILTERORDER));
103 WebRtcSpl_FilterARFastQ12(
104 sampleMa, sampleAr,
105 syntDenum, LPC_FILTERORDER+1, 2 * len);
106
107 tmp1 = &sampleAr[len-1];
108 tmp2 = &sampleAr[2*len-1];
109 tmp3 = Out_fix;
110 for(k=0;k<len;k++){
111 (*tmp3) = (*tmp1) + (*tmp2);
112 tmp1--;
113 tmp2--;
114 tmp3++;
115 }
116 }
117