1 2 /****************************************************************** 3 4 iLBC Speech Coder ANSI-C Source Code 5 6 LPCencode.c 7 8 Copyright (C) The Internet Society (2004). 9 All Rights Reserved. 10 11 ******************************************************************/ 12 13 #include <string.h> 14 15 #include "iLBC_define.h" 16 #include "helpfun.h" 17 #include "lsf.h" 18 #include "constants.h" 19 20 21 22 23 24 /*----------------------------------------------------------------* 25 * lpc analysis (subrutine to LPCencode) 26 *---------------------------------------------------------------*/ 27 SimpleAnalysis(float * lsf,float * data,iLBC_Enc_Inst_t * iLBCenc_inst)28 void SimpleAnalysis( 29 float *lsf, /* (o) lsf coefficients */ 30 float *data, /* (i) new data vector */ 31 iLBC_Enc_Inst_t *iLBCenc_inst 32 /* (i/o) the encoder state structure */ 33 ){ 34 int k, is; 35 float temp[BLOCKL_MAX], lp[LPC_FILTERORDER + 1]; 36 float lp2[LPC_FILTERORDER + 1]; 37 float r[LPC_FILTERORDER + 1]; 38 39 is=LPC_LOOKBACK+BLOCKL_MAX-iLBCenc_inst->blockl; 40 memcpy(iLBCenc_inst->lpc_buffer+is,data, 41 iLBCenc_inst->blockl*sizeof(float)); 42 43 /* No lookahead, last window is asymmetric */ 44 45 for (k = 0; k < iLBCenc_inst->lpc_n; k++) { 46 47 is = LPC_LOOKBACK; 48 49 if (k < (iLBCenc_inst->lpc_n - 1)) { 50 window(temp, lpc_winTbl, 51 iLBCenc_inst->lpc_buffer, BLOCKL_MAX); 52 } else { 53 window(temp, lpc_asymwinTbl, 54 iLBCenc_inst->lpc_buffer + is, BLOCKL_MAX); 55 } 56 57 autocorr(r, temp, BLOCKL_MAX, LPC_FILTERORDER); 58 window(r, r, lpc_lagwinTbl, LPC_FILTERORDER + 1); 59 60 levdurb(lp, temp, r, LPC_FILTERORDER); 61 bwexpand(lp2, lp, LPC_CHIRP_SYNTDENUM, LPC_FILTERORDER+1); 62 63 a2lsf(lsf + k*LPC_FILTERORDER, lp2); 64 } 65 is=LPC_LOOKBACK+BLOCKL_MAX-iLBCenc_inst->blockl; 66 memmove(iLBCenc_inst->lpc_buffer, 67 iLBCenc_inst->lpc_buffer+LPC_LOOKBACK+BLOCKL_MAX-is, 68 is*sizeof(float)); 69 } 70 71 /*----------------------------------------------------------------* 72 73 74 75 76 77 * lsf interpolator and conversion from lsf to a coefficients 78 * (subrutine to SimpleInterpolateLSF) 79 *---------------------------------------------------------------*/ 80 LSFinterpolate2a_enc(float * a,float * lsf1,float * lsf2,float coef,long length)81 void LSFinterpolate2a_enc( 82 float *a, /* (o) lpc coefficients */ 83 float *lsf1,/* (i) first set of lsf coefficients */ 84 float *lsf2,/* (i) second set of lsf coefficients */ 85 float coef, /* (i) weighting coefficient to use between 86 lsf1 and lsf2 */ 87 long length /* (i) length of coefficient vectors */ 88 ){ 89 float lsftmp[LPC_FILTERORDER]; 90 91 interpolate(lsftmp, lsf1, lsf2, coef, length); 92 lsf2a(a, lsftmp); 93 } 94 95 /*----------------------------------------------------------------* 96 * lsf interpolator (subrutine to LPCencode) 97 *---------------------------------------------------------------*/ 98 SimpleInterpolateLSF(float * syntdenum,float * weightdenum,float * lsf,float * lsfdeq,float * lsfold,float * lsfdeqold,int length,iLBC_Enc_Inst_t * iLBCenc_inst)99 void SimpleInterpolateLSF( 100 float *syntdenum, /* (o) the synthesis filter denominator 101 resulting from the quantized 102 interpolated lsf */ 103 float *weightdenum, /* (o) the weighting filter denominator 104 resulting from the unquantized 105 interpolated lsf */ 106 float *lsf, /* (i) the unquantized lsf coefficients */ 107 float *lsfdeq, /* (i) the dequantized lsf coefficients */ 108 float *lsfold, /* (i) the unquantized lsf coefficients of 109 the previous signal frame */ 110 float *lsfdeqold, /* (i) the dequantized lsf coefficients of 111 the previous signal frame */ 112 int length, /* (i) should equate LPC_FILTERORDER */ 113 iLBC_Enc_Inst_t *iLBCenc_inst 114 /* (i/o) the encoder state structure */ 115 ){ 116 int i, pos, lp_length; 117 float lp[LPC_FILTERORDER + 1], *lsf2, *lsfdeq2; 118 119 lsf2 = lsf + length; 120 lsfdeq2 = lsfdeq + length; 121 lp_length = length + 1; 122 123 if (iLBCenc_inst->mode==30) { 124 /* sub-frame 1: Interpolation between old and first 125 126 127 128 129 130 set of lsf coefficients */ 131 132 LSFinterpolate2a_enc(lp, lsfdeqold, lsfdeq, 133 lsf_weightTbl_30ms[0], length); 134 memcpy(syntdenum,lp,lp_length*sizeof(float)); 135 LSFinterpolate2a_enc(lp, lsfold, lsf, 136 lsf_weightTbl_30ms[0], length); 137 bwexpand(weightdenum, lp, LPC_CHIRP_WEIGHTDENUM, lp_length); 138 139 /* sub-frame 2 to 6: Interpolation between first 140 and second set of lsf coefficients */ 141 142 pos = lp_length; 143 for (i = 1; i < iLBCenc_inst->nsub; i++) { 144 LSFinterpolate2a_enc(lp, lsfdeq, lsfdeq2, 145 lsf_weightTbl_30ms[i], length); 146 memcpy(syntdenum + pos,lp,lp_length*sizeof(float)); 147 148 LSFinterpolate2a_enc(lp, lsf, lsf2, 149 lsf_weightTbl_30ms[i], length); 150 bwexpand(weightdenum + pos, lp, 151 LPC_CHIRP_WEIGHTDENUM, lp_length); 152 pos += lp_length; 153 } 154 } 155 else { 156 pos = 0; 157 for (i = 0; i < iLBCenc_inst->nsub; i++) { 158 LSFinterpolate2a_enc(lp, lsfdeqold, lsfdeq, 159 lsf_weightTbl_20ms[i], length); 160 memcpy(syntdenum+pos,lp,lp_length*sizeof(float)); 161 LSFinterpolate2a_enc(lp, lsfold, lsf, 162 lsf_weightTbl_20ms[i], length); 163 bwexpand(weightdenum+pos, lp, 164 LPC_CHIRP_WEIGHTDENUM, lp_length); 165 pos += lp_length; 166 } 167 } 168 169 /* update memory */ 170 171 if (iLBCenc_inst->mode==30) { 172 memcpy(lsfold, lsf2, length*sizeof(float)); 173 memcpy(lsfdeqold, lsfdeq2, length*sizeof(float)); 174 } 175 else { 176 memcpy(lsfold, lsf, length*sizeof(float)); 177 memcpy(lsfdeqold, lsfdeq, length*sizeof(float)); 178 179 180 181 182 183 } 184 } 185 186 /*----------------------------------------------------------------* 187 * lsf quantizer (subrutine to LPCencode) 188 *---------------------------------------------------------------*/ 189 SimplelsfQ(float * lsfdeq,int * index,float * lsf,int lpc_n)190 void SimplelsfQ( 191 float *lsfdeq, /* (o) dequantized lsf coefficients 192 (dimension FILTERORDER) */ 193 int *index, /* (o) quantization index */ 194 float *lsf, /* (i) the lsf coefficient vector to be 195 quantized (dimension FILTERORDER ) */ 196 int lpc_n /* (i) number of lsf sets to quantize */ 197 ){ 198 /* Quantize first LSF with memoryless split VQ */ 199 SplitVQ(lsfdeq, index, lsf, lsfCbTbl, LSF_NSPLIT, 200 dim_lsfCbTbl, size_lsfCbTbl); 201 202 if (lpc_n==2) { 203 /* Quantize second LSF with memoryless split VQ */ 204 SplitVQ(lsfdeq + LPC_FILTERORDER, index + LSF_NSPLIT, 205 lsf + LPC_FILTERORDER, lsfCbTbl, LSF_NSPLIT, 206 dim_lsfCbTbl, size_lsfCbTbl); 207 } 208 } 209 210 /*----------------------------------------------------------------* 211 * lpc encoder 212 *---------------------------------------------------------------*/ 213 LPCencode(float * syntdenum,float * weightdenum,int * lsf_index,float * data,iLBC_Enc_Inst_t * iLBCenc_inst)214 void LPCencode( 215 float *syntdenum, /* (i/o) synthesis filter coefficients 216 before/after encoding */ 217 float *weightdenum, /* (i/o) weighting denumerator 218 coefficients before/after 219 encoding */ 220 int *lsf_index, /* (o) lsf quantization index */ 221 float *data, /* (i) lsf coefficients to quantize */ 222 iLBC_Enc_Inst_t *iLBCenc_inst 223 /* (i/o) the encoder state structure */ 224 ){ 225 float lsf[LPC_FILTERORDER * LPC_N_MAX]; 226 float lsfdeq[LPC_FILTERORDER * LPC_N_MAX]; 227 int change=0; 228 229 SimpleAnalysis(lsf, data, iLBCenc_inst); 230 SimplelsfQ(lsfdeq, lsf_index, lsf, iLBCenc_inst->lpc_n); 231 232 233 234 235 236 change=LSF_check(lsfdeq, LPC_FILTERORDER, iLBCenc_inst->lpc_n); 237 SimpleInterpolateLSF(syntdenum, weightdenum, 238 lsf, lsfdeq, iLBCenc_inst->lsfold, 239 iLBCenc_inst->lsfdeqold, LPC_FILTERORDER, iLBCenc_inst); 240 } 241 242