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 "defines.h"
20 #include "constants.h"
21
22 /*----------------------------------------------------------------*
23 * decoding of the start state
24 *---------------------------------------------------------------*/
25
WebRtcIlbcfix_StateConstruct(int16_t idxForMax,int16_t * idxVec,int16_t * syntDenum,int16_t * Out_fix,int16_t len)26 void WebRtcIlbcfix_StateConstruct(
27 int16_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 int16_t len /* (i) length of a state vector */
33 ) {
34 int 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) ((WEBRTC_SPL_MUL_16_16(maxVal,WebRtcIlbcfix_kStateSq3[(*tmp2)])+(int32_t)2097152) >> 22);
64 tmp1++;
65 tmp2--;
66 }
67 } else if (idxForMax<59) {
68 for(k=0; k<len; k++){
69 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 262144 (= 0.5 << 19)
70 maxVal is in Q5 and result is in Q(-1) */
71 (*tmp1) = (int16_t) ((WEBRTC_SPL_MUL_16_16(maxVal,WebRtcIlbcfix_kStateSq3[(*tmp2)])+(int32_t)262144) >> 19);
72 tmp1++;
73 tmp2--;
74 }
75 } else {
76 for(k=0; k<len; k++){
77 /*the shifting is due to the Q13 in sq4_fixQ13[i], also the adding of 65536 (= 0.5 << 17)
78 maxVal is in Q3 and result is in Q(-1) */
79 (*tmp1) = (int16_t) ((WEBRTC_SPL_MUL_16_16(maxVal,WebRtcIlbcfix_kStateSq3[(*tmp2)])+(int32_t)65536) >> 17);
80 tmp1++;
81 tmp2--;
82 }
83 }
84
85 /* Set the rest of the data to zero */
86 WebRtcSpl_MemSetW16(&sampleVal[len], 0, len);
87
88 /* circular convolution with all-pass filter */
89
90 /* Set the state to zero */
91 WebRtcSpl_MemSetW16(sampleValVec, 0, (LPC_FILTERORDER));
92
93 /* Run MA filter + AR filter */
94 WebRtcSpl_FilterMAFastQ12(
95 sampleVal, sampleMa,
96 numerator, LPC_FILTERORDER+1, (int16_t)(len + LPC_FILTERORDER));
97 WebRtcSpl_MemSetW16(&sampleMa[len + LPC_FILTERORDER], 0, (len - LPC_FILTERORDER));
98 WebRtcSpl_FilterARFastQ12(
99 sampleMa, sampleAr,
100 syntDenum, LPC_FILTERORDER+1, (int16_t)(2*len));
101
102 tmp1 = &sampleAr[len-1];
103 tmp2 = &sampleAr[2*len-1];
104 tmp3 = Out_fix;
105 for(k=0;k<len;k++){
106 (*tmp3) = (*tmp1) + (*tmp2);
107 tmp1--;
108 tmp2--;
109 tmp3++;
110 }
111 }
112