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_StateSearch.c
16
17 ******************************************************************/
18
19 #include "defines.h"
20 #include "constants.h"
21 #include "abs_quant.h"
22
23 /*----------------------------------------------------------------*
24 * encoding of start state
25 *---------------------------------------------------------------*/
26
WebRtcIlbcfix_StateSearch(IlbcEncoder * iLBCenc_inst,iLBC_bits * iLBC_encbits,int16_t * residual,int16_t * syntDenum,int16_t * weightDenum)27 void WebRtcIlbcfix_StateSearch(
28 IlbcEncoder *iLBCenc_inst,
29 /* (i) Encoder instance */
30 iLBC_bits *iLBC_encbits,/* (i/o) Encoded bits (output idxForMax
31 and idxVec, input state_first) */
32 int16_t *residual, /* (i) target residual vector */
33 int16_t *syntDenum, /* (i) lpc synthesis filter */
34 int16_t *weightDenum /* (i) weighting filter denuminator */
35 ) {
36 size_t k, index;
37 int16_t maxVal;
38 int16_t scale, shift;
39 int32_t maxValsq;
40 int16_t scaleRes;
41 int16_t max;
42 int i;
43 /* Stack based */
44 int16_t numerator[1+LPC_FILTERORDER];
45 int16_t residualLongVec[2*STATE_SHORT_LEN_30MS+LPC_FILTERORDER];
46 int16_t sampleMa[2*STATE_SHORT_LEN_30MS];
47 int16_t *residualLong = &residualLongVec[LPC_FILTERORDER];
48 int16_t *sampleAr = residualLong;
49
50 /* Scale to maximum 12 bits to avoid saturation in circular convolution filter */
51 max = WebRtcSpl_MaxAbsValueW16(residual, iLBCenc_inst->state_short_len);
52 scaleRes = WebRtcSpl_GetSizeInBits(max)-12;
53 scaleRes = WEBRTC_SPL_MAX(0, scaleRes);
54 /* Set up the filter coefficients for the circular convolution */
55 for (i=0; i<LPC_FILTERORDER+1; i++) {
56 numerator[i] = (syntDenum[LPC_FILTERORDER-i]>>scaleRes);
57 }
58
59 /* Copy the residual to a temporary buffer that we can filter
60 * and set the remaining samples to zero.
61 */
62 WEBRTC_SPL_MEMCPY_W16(residualLong, residual, iLBCenc_inst->state_short_len);
63 WebRtcSpl_MemSetW16(residualLong + iLBCenc_inst->state_short_len, 0, iLBCenc_inst->state_short_len);
64
65 /* Run the Zero-Pole filter (Ciurcular convolution) */
66 WebRtcSpl_MemSetW16(residualLongVec, 0, LPC_FILTERORDER);
67 WebRtcSpl_FilterMAFastQ12(residualLong, sampleMa, numerator,
68 LPC_FILTERORDER + 1,
69 iLBCenc_inst->state_short_len + LPC_FILTERORDER);
70 WebRtcSpl_MemSetW16(&sampleMa[iLBCenc_inst->state_short_len + LPC_FILTERORDER], 0, iLBCenc_inst->state_short_len - LPC_FILTERORDER);
71
72 WebRtcSpl_FilterARFastQ12(
73 sampleMa, sampleAr,
74 syntDenum, LPC_FILTERORDER+1, 2 * iLBCenc_inst->state_short_len);
75
76 for(k=0;k<iLBCenc_inst->state_short_len;k++){
77 sampleAr[k] += sampleAr[k+iLBCenc_inst->state_short_len];
78 }
79
80 /* Find maximum absolute value in the vector */
81 maxVal=WebRtcSpl_MaxAbsValueW16(sampleAr, iLBCenc_inst->state_short_len);
82
83 /* Find the best index */
84
85 if ((((int32_t)maxVal)<<scaleRes)<23170) {
86 maxValsq=((int32_t)maxVal*maxVal)<<(2+2*scaleRes);
87 } else {
88 maxValsq=(int32_t)WEBRTC_SPL_WORD32_MAX;
89 }
90
91 index=0;
92 for (i=0;i<63;i++) {
93
94 if (maxValsq>=WebRtcIlbcfix_kChooseFrgQuant[i]) {
95 index=i+1;
96 } else {
97 i=63;
98 }
99 }
100 iLBC_encbits->idxForMax=index;
101
102 /* Rescale the vector before quantization */
103 scale=WebRtcIlbcfix_kScale[index];
104
105 if (index<27) { /* scale table is in Q16, fout[] is in Q(-1) and we want the result to be in Q11 */
106 shift=4;
107 } else { /* scale table is in Q21, fout[] is in Q(-1) and we want the result to be in Q11 */
108 shift=9;
109 }
110
111 /* Set up vectors for AbsQuant and rescale it with the scale factor */
112 WebRtcSpl_ScaleVectorWithSat(sampleAr, sampleAr, scale,
113 iLBCenc_inst->state_short_len, (int16_t)(shift-scaleRes));
114
115 /* Quantize the values in fout[] */
116 WebRtcIlbcfix_AbsQuant(iLBCenc_inst, iLBC_encbits, sampleAr, weightDenum);
117
118 return;
119 }
120