1 /* 2 * Copyright (c) 2012 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 * decode_B.c 13 * 14 * This file contains definition of funtions for decoding. 15 * Decoding of lower-band, including normal-decoding and RCU decoding. 16 * Decoding of upper-band, including 8-12 kHz, when the bandwidth is 17 * 0-12 kHz, and 8-16 kHz, when the bandwidth is 0-16 kHz. 18 * 19 */ 20 21 22 #include "codec.h" 23 #include "entropy_coding.h" 24 #include "pitch_estimator.h" 25 #include "bandwidth_estimator.h" 26 #include "structs.h" 27 #include "settings.h" 28 29 #include <stdio.h> 30 #include <stdlib.h> 31 #include <string.h> 32 33 34 /* 35 * function to decode the bitstream 36 * returns the total number of bytes in the stream 37 */ 38 int WebRtcIsac_DecodeLb(const TransformTables* transform_tables, 39 float* signal_out, ISACLBDecStruct* ISACdecLB_obj, 40 int16_t* current_framesamples, 41 int16_t isRCUPayload) { 42 int k; 43 int len, err; 44 int16_t bandwidthInd; 45 46 float LP_dec_float[FRAMESAMPLES_HALF]; 47 float HP_dec_float[FRAMESAMPLES_HALF]; 48 49 double LPw[FRAMESAMPLES_HALF]; 50 double HPw[FRAMESAMPLES_HALF]; 51 double LPw_pf[FRAMESAMPLES_HALF]; 52 53 double lo_filt_coef[(ORDERLO + 1)*SUBFRAMES]; 54 double hi_filt_coef[(ORDERHI + 1)*SUBFRAMES]; 55 56 double real_f[FRAMESAMPLES_HALF]; 57 double imag_f[FRAMESAMPLES_HALF]; 58 59 double PitchLags[4]; 60 double PitchGains[4]; 61 double AvgPitchGain; 62 int16_t PitchGains_Q12[4]; 63 int16_t AvgPitchGain_Q12; 64 65 float gain; 66 67 int frame_nb; /* counter */ 68 int frame_mode; /* 0 30ms, 1 for 60ms */ 69 /* Processed_samples: 480 (30, 60 ms). Cannot take other values. */ 70 71 WebRtcIsac_ResetBitstream(&(ISACdecLB_obj->bitstr_obj)); 72 73 len = 0; 74 75 /* Decode framelength and BW estimation - not used, 76 only for stream pointer*/ 77 err = WebRtcIsac_DecodeFrameLen(&ISACdecLB_obj->bitstr_obj, 78 current_framesamples); 79 if (err < 0) { 80 return err; 81 } 82 83 /* Frame_mode: 84 * 0: indicates 30 ms frame (480 samples) 85 * 1: indicates 60 ms frame (960 samples) */ 86 frame_mode = *current_framesamples / MAX_FRAMESAMPLES; 87 88 err = WebRtcIsac_DecodeSendBW(&ISACdecLB_obj->bitstr_obj, &bandwidthInd); 89 if (err < 0) { 90 return err; 91 } 92 93 /* One loop if it's one frame (20 or 30ms), 2 loops if 2 frames 94 bundled together (60ms). */ 95 for (frame_nb = 0; frame_nb <= frame_mode; frame_nb++) { 96 /* Decode & de-quantize pitch parameters */ 97 err = WebRtcIsac_DecodePitchGain(&ISACdecLB_obj->bitstr_obj, 98 PitchGains_Q12); 99 if (err < 0) { 100 return err; 101 } 102 103 err = WebRtcIsac_DecodePitchLag(&ISACdecLB_obj->bitstr_obj, PitchGains_Q12, 104 PitchLags); 105 if (err < 0) { 106 return err; 107 } 108 109 AvgPitchGain_Q12 = (PitchGains_Q12[0] + PitchGains_Q12[1] + 110 PitchGains_Q12[2] + PitchGains_Q12[3]) >> 2; 111 112 /* Decode & de-quantize filter coefficients. */ 113 err = WebRtcIsac_DecodeLpc(&ISACdecLB_obj->bitstr_obj, lo_filt_coef, 114 hi_filt_coef); 115 if (err < 0) { 116 return err; 117 } 118 /* Decode & de-quantize spectrum. */ 119 len = WebRtcIsac_DecodeSpec(&ISACdecLB_obj->bitstr_obj, AvgPitchGain_Q12, 120 kIsacLowerBand, real_f, imag_f); 121 if (len < 0) { 122 return len; 123 } 124 125 /* Inverse transform. */ 126 WebRtcIsac_Spec2time(transform_tables, real_f, imag_f, LPw, HPw, 127 &ISACdecLB_obj->fftstr_obj); 128 129 /* Convert PitchGains back to float for pitchfilter_post */ 130 for (k = 0; k < 4; k++) { 131 PitchGains[k] = ((float)PitchGains_Q12[k]) / 4096; 132 } 133 if (isRCUPayload) { 134 for (k = 0; k < 240; k++) { 135 LPw[k] *= RCU_TRANSCODING_SCALE_INVERSE; 136 HPw[k] *= RCU_TRANSCODING_SCALE_INVERSE; 137 } 138 } 139 140 /* Inverse pitch filter. */ 141 WebRtcIsac_PitchfilterPost(LPw, LPw_pf, &ISACdecLB_obj->pitchfiltstr_obj, 142 PitchLags, PitchGains); 143 /* Convert AvgPitchGain back to float for computation of gain. */ 144 AvgPitchGain = ((float)AvgPitchGain_Q12) / 4096; 145 gain = 1.0f - 0.45f * (float)AvgPitchGain; 146 147 for (k = 0; k < FRAMESAMPLES_HALF; k++) { 148 /* Reduce gain to compensate for pitch enhancer. */ 149 LPw_pf[k] *= gain; 150 } 151 152 if (isRCUPayload) { 153 for (k = 0; k < FRAMESAMPLES_HALF; k++) { 154 /* Compensation for transcoding gain changes. */ 155 LPw_pf[k] *= RCU_TRANSCODING_SCALE; 156 HPw[k] *= RCU_TRANSCODING_SCALE; 157 } 158 } 159 /* Perceptual post-filtering (using normalized lattice filter). */ 160 WebRtcIsac_NormLatticeFilterAr( 161 ORDERLO, ISACdecLB_obj->maskfiltstr_obj.PostStateLoF, 162 (ISACdecLB_obj->maskfiltstr_obj).PostStateLoG, LPw_pf, lo_filt_coef, 163 LP_dec_float); 164 WebRtcIsac_NormLatticeFilterAr( 165 ORDERHI, ISACdecLB_obj->maskfiltstr_obj.PostStateHiF, 166 (ISACdecLB_obj->maskfiltstr_obj).PostStateHiG, HPw, hi_filt_coef, 167 HP_dec_float); 168 169 /* Recombine the 2 bands. */ 170 WebRtcIsac_FilterAndCombineFloat(LP_dec_float, HP_dec_float, 171 signal_out + frame_nb * FRAMESAMPLES, 172 &ISACdecLB_obj->postfiltbankstr_obj); 173 } 174 return len; 175 } 176 177 178 /* 179 * This decode function is called when the codec is operating in 16 kHz 180 * bandwidth to decode the upperband, i.e. 8-16 kHz. 181 * 182 * Contrary to lower-band, the upper-band (8-16 kHz) is not split in 183 * frequency, but split to 12 sub-frames, i.e. twice as lower-band. 184 */ 185 int WebRtcIsac_DecodeUb16(const TransformTables* transform_tables, 186 float* signal_out, ISACUBDecStruct* ISACdecUB_obj, 187 int16_t isRCUPayload) { 188 int len, err; 189 190 double halfFrameFirst[FRAMESAMPLES_HALF]; 191 double halfFrameSecond[FRAMESAMPLES_HALF]; 192 193 double percepFilterParam[(UB_LPC_ORDER + 1) * (SUBFRAMES << 1) + 194 (UB_LPC_ORDER + 1)]; 195 196 double real_f[FRAMESAMPLES_HALF]; 197 double imag_f[FRAMESAMPLES_HALF]; 198 const int16_t kAveragePitchGain = 0; /* No pitch-gain for upper-band. */ 199 len = 0; 200 201 /* Decode & de-quantize filter coefficients. */ 202 memset(percepFilterParam, 0, sizeof(percepFilterParam)); 203 err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj, 204 percepFilterParam, isac16kHz); 205 if (err < 0) { 206 return err; 207 } 208 209 /* Decode & de-quantize spectrum. */ 210 len = WebRtcIsac_DecodeSpec(&ISACdecUB_obj->bitstr_obj, kAveragePitchGain, 211 kIsacUpperBand16, real_f, imag_f); 212 if (len < 0) { 213 return len; 214 } 215 if (isRCUPayload) { 216 int n; 217 for (n = 0; n < 240; n++) { 218 real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 219 imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 220 } 221 } 222 /* Inverse transform. */ 223 WebRtcIsac_Spec2time(transform_tables, 224 real_f, imag_f, halfFrameFirst, halfFrameSecond, 225 &ISACdecUB_obj->fftstr_obj); 226 227 /* Perceptual post-filtering (using normalized lattice filter). */ 228 WebRtcIsac_NormLatticeFilterAr( 229 UB_LPC_ORDER, ISACdecUB_obj->maskfiltstr_obj.PostStateLoF, 230 (ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameFirst, 231 &percepFilterParam[(UB_LPC_ORDER + 1)], signal_out); 232 233 WebRtcIsac_NormLatticeFilterAr( 234 UB_LPC_ORDER, ISACdecUB_obj->maskfiltstr_obj.PostStateLoF, 235 (ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameSecond, 236 &percepFilterParam[(UB_LPC_ORDER + 1) * SUBFRAMES + (UB_LPC_ORDER + 1)], 237 &signal_out[FRAMESAMPLES_HALF]); 238 239 return len; 240 } 241 242 /* 243 * This decode function is called when the codec operates at 0-12 kHz 244 * bandwidth to decode the upperband, i.e. 8-12 kHz. 245 * 246 * At the encoder the upper-band is split into two band, 8-12 kHz & 12-16 247 * kHz, and only 8-12 kHz is encoded. At the decoder, 8-12 kHz band is 248 * reconstructed and 12-16 kHz replaced with zeros. Then two bands 249 * are combined, to reconstruct the upperband 8-16 kHz. 250 */ 251 int WebRtcIsac_DecodeUb12(const TransformTables* transform_tables, 252 float* signal_out, ISACUBDecStruct* ISACdecUB_obj, 253 int16_t isRCUPayload) { 254 int len, err; 255 256 float LP_dec_float[FRAMESAMPLES_HALF]; 257 float HP_dec_float[FRAMESAMPLES_HALF]; 258 259 double LPw[FRAMESAMPLES_HALF]; 260 double HPw[FRAMESAMPLES_HALF]; 261 262 double percepFilterParam[(UB_LPC_ORDER + 1)*SUBFRAMES]; 263 264 double real_f[FRAMESAMPLES_HALF]; 265 double imag_f[FRAMESAMPLES_HALF]; 266 const int16_t kAveragePitchGain = 0; /* No pitch-gain for upper-band. */ 267 len = 0; 268 269 /* Decode & dequantize filter coefficients. */ 270 err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj, 271 percepFilterParam, isac12kHz); 272 if (err < 0) { 273 return err; 274 } 275 276 /* Decode & de-quantize spectrum. */ 277 len = WebRtcIsac_DecodeSpec(&ISACdecUB_obj->bitstr_obj, kAveragePitchGain, 278 kIsacUpperBand12, real_f, imag_f); 279 if (len < 0) { 280 return len; 281 } 282 283 if (isRCUPayload) { 284 int n; 285 for (n = 0; n < 240; n++) { 286 real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 287 imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 288 } 289 } 290 /* Inverse transform. */ 291 WebRtcIsac_Spec2time(transform_tables, 292 real_f, imag_f, LPw, HPw, &ISACdecUB_obj->fftstr_obj); 293 /* perceptual post-filtering (using normalized lattice filter) */ 294 WebRtcIsac_NormLatticeFilterAr(UB_LPC_ORDER, 295 ISACdecUB_obj->maskfiltstr_obj.PostStateLoF, 296 (ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, 297 LPw, percepFilterParam, LP_dec_float); 298 /* Zero for 12-16 kHz. */ 299 memset(HP_dec_float, 0, sizeof(float) * (FRAMESAMPLES_HALF)); 300 /* Recombine the 2 bands. */ 301 WebRtcIsac_FilterAndCombineFloat(HP_dec_float, LP_dec_float, signal_out, 302 &ISACdecUB_obj->postfiltbankstr_obj); 303 return len; 304 } 305
