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(float* signal_out, ISACLBDecStruct* ISACdecLB_obj, 39 WebRtc_Word16* current_framesamples, 40 WebRtc_Word16 isRCUPayload) { 41 int k; 42 int len, err; 43 WebRtc_Word16 bandwidthInd; 44 45 float LP_dec_float[FRAMESAMPLES_HALF]; 46 float HP_dec_float[FRAMESAMPLES_HALF]; 47 48 double LPw[FRAMESAMPLES_HALF]; 49 double HPw[FRAMESAMPLES_HALF]; 50 double LPw_pf[FRAMESAMPLES_HALF]; 51 52 double lo_filt_coef[(ORDERLO + 1)*SUBFRAMES]; 53 double hi_filt_coef[(ORDERHI + 1)*SUBFRAMES]; 54 55 double real_f[FRAMESAMPLES_HALF]; 56 double imag_f[FRAMESAMPLES_HALF]; 57 58 double PitchLags[4]; 59 double PitchGains[4]; 60 double AvgPitchGain; 61 WebRtc_Word16 PitchGains_Q12[4]; 62 WebRtc_Word16 AvgPitchGain_Q12; 63 64 float gain; 65 66 int frame_nb; /* counter */ 67 int frame_mode; /* 0 30ms, 1 for 60ms */ 68 /* Processed_samples: 480 (30, 60 ms). Cannot take other values. */ 69 70 WebRtcIsac_ResetBitstream(&(ISACdecLB_obj->bitstr_obj)); 71 72 len = 0; 73 74 /* Decode framelength and BW estimation - not used, 75 only for stream pointer*/ 76 err = WebRtcIsac_DecodeFrameLen(&ISACdecLB_obj->bitstr_obj, 77 current_framesamples); 78 if (err < 0) { 79 return err; 80 } 81 82 /* Frame_mode: 83 * 0: indicates 30 ms frame (480 samples) 84 * 1: indicates 60 ms frame (960 samples) */ 85 frame_mode = *current_framesamples / MAX_FRAMESAMPLES; 86 87 err = WebRtcIsac_DecodeSendBW(&ISACdecLB_obj->bitstr_obj, &bandwidthInd); 88 if (err < 0) { 89 return err; 90 } 91 92 /* One loop if it's one frame (20 or 30ms), 2 loops if 2 frames 93 bundled together (60ms). */ 94 for (frame_nb = 0; frame_nb <= frame_mode; frame_nb++) { 95 /* Decode & de-quantize pitch parameters */ 96 err = WebRtcIsac_DecodePitchGain(&ISACdecLB_obj->bitstr_obj, 97 PitchGains_Q12); 98 if (err < 0) { 99 return err; 100 } 101 102 err = WebRtcIsac_DecodePitchLag(&ISACdecLB_obj->bitstr_obj, PitchGains_Q12, 103 PitchLags); 104 if (err < 0) { 105 return err; 106 } 107 108 AvgPitchGain_Q12 = (PitchGains_Q12[0] + PitchGains_Q12[1] + 109 PitchGains_Q12[2] + PitchGains_Q12[3]) >> 2; 110 111 /* Decode & de-quantize filter coefficients. */ 112 err = WebRtcIsac_DecodeLpc(&ISACdecLB_obj->bitstr_obj, lo_filt_coef, 113 hi_filt_coef); 114 if (err < 0) { 115 return err; 116 } 117 /* Decode & de-quantize spectrum. */ 118 len = WebRtcIsac_DecodeSpec(&ISACdecLB_obj->bitstr_obj, AvgPitchGain_Q12, 119 kIsacLowerBand, real_f, imag_f); 120 if (len < 0) { 121 return len; 122 } 123 124 /* Inverse transform. */ 125 WebRtcIsac_Spec2time(real_f, imag_f, LPw, HPw, 126 &ISACdecLB_obj->fftstr_obj); 127 128 /* Convert PitchGains back to float for pitchfilter_post */ 129 for (k = 0; k < 4; k++) { 130 PitchGains[k] = ((float)PitchGains_Q12[k]) / 4096; 131 } 132 if (isRCUPayload) { 133 for (k = 0; k < 240; k++) { 134 LPw[k] *= RCU_TRANSCODING_SCALE_INVERSE; 135 HPw[k] *= RCU_TRANSCODING_SCALE_INVERSE; 136 } 137 } 138 139 /* Inverse pitch filter. */ 140 WebRtcIsac_PitchfilterPost(LPw, LPw_pf, &ISACdecLB_obj->pitchfiltstr_obj, 141 PitchLags, PitchGains); 142 /* Convert AvgPitchGain back to float for computation of gain. */ 143 AvgPitchGain = ((float)AvgPitchGain_Q12) / 4096; 144 gain = 1.0f - 0.45f * (float)AvgPitchGain; 145 146 for (k = 0; k < FRAMESAMPLES_HALF; k++) { 147 /* Reduce gain to compensate for pitch enhancer. */ 148 LPw_pf[k] *= gain; 149 } 150 151 if (isRCUPayload) { 152 for (k = 0; k < FRAMESAMPLES_HALF; k++) { 153 /* Compensation for transcoding gain changes. */ 154 LPw_pf[k] *= RCU_TRANSCODING_SCALE; 155 HPw[k] *= RCU_TRANSCODING_SCALE; 156 } 157 } 158 /* Perceptual post-filtering (using normalized lattice filter). */ 159 WebRtcIsac_NormLatticeFilterAr( 160 ORDERLO, ISACdecLB_obj->maskfiltstr_obj.PostStateLoF, 161 (ISACdecLB_obj->maskfiltstr_obj).PostStateLoG, LPw_pf, lo_filt_coef, 162 LP_dec_float); 163 WebRtcIsac_NormLatticeFilterAr( 164 ORDERHI, ISACdecLB_obj->maskfiltstr_obj.PostStateHiF, 165 (ISACdecLB_obj->maskfiltstr_obj).PostStateHiG, HPw, hi_filt_coef, 166 HP_dec_float); 167 168 /* Recombine the 2 bands. */ 169 WebRtcIsac_FilterAndCombineFloat(LP_dec_float, HP_dec_float, 170 signal_out + frame_nb * FRAMESAMPLES, 171 &ISACdecLB_obj->postfiltbankstr_obj); 172 } 173 return len; 174 } 175 176 177 /* 178 * This decode function is called when the codec is operating in 16 kHz 179 * bandwidth to decode the upperband, i.e. 8-16 kHz. 180 * 181 * Contrary to lower-band, the upper-band (8-16 kHz) is not split in 182 * frequency, but split to 12 sub-frames, i.e. twice as lower-band. 183 */ 184 int WebRtcIsac_DecodeUb16(float* signal_out, ISACUBDecStruct* ISACdecUB_obj, 185 WebRtc_Word16 isRCUPayload) { 186 int len, err; 187 188 double halfFrameFirst[FRAMESAMPLES_HALF]; 189 double halfFrameSecond[FRAMESAMPLES_HALF]; 190 191 double percepFilterParam[(UB_LPC_ORDER + 1) * (SUBFRAMES << 1) + 192 (UB_LPC_ORDER + 1)]; 193 194 double real_f[FRAMESAMPLES_HALF]; 195 double imag_f[FRAMESAMPLES_HALF]; 196 const WebRtc_Word16 kAveragePitchGain = 0; /* No pitch-gain for upper-band. */ 197 len = 0; 198 199 /* Decode & de-quantize filter coefficients. */ 200 memset(percepFilterParam, 0, sizeof(percepFilterParam)); 201 err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj, 202 percepFilterParam, isac16kHz); 203 if (err < 0) { 204 return err; 205 } 206 207 /* Decode & de-quantize spectrum. */ 208 len = WebRtcIsac_DecodeSpec(&ISACdecUB_obj->bitstr_obj, kAveragePitchGain, 209 kIsacUpperBand16, real_f, imag_f); 210 if (len < 0) { 211 return len; 212 } 213 if (isRCUPayload) { 214 int n; 215 for (n = 0; n < 240; n++) { 216 real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 217 imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 218 } 219 } 220 /* Inverse transform. */ 221 WebRtcIsac_Spec2time(real_f, imag_f, halfFrameFirst, halfFrameSecond, 222 &ISACdecUB_obj->fftstr_obj); 223 224 /* Perceptual post-filtering (using normalized lattice filter). */ 225 WebRtcIsac_NormLatticeFilterAr( 226 UB_LPC_ORDER, ISACdecUB_obj->maskfiltstr_obj.PostStateLoF, 227 (ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameFirst, 228 &percepFilterParam[(UB_LPC_ORDER + 1)], signal_out); 229 230 WebRtcIsac_NormLatticeFilterAr( 231 UB_LPC_ORDER, ISACdecUB_obj->maskfiltstr_obj.PostStateLoF, 232 (ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameSecond, 233 &percepFilterParam[(UB_LPC_ORDER + 1) * SUBFRAMES + (UB_LPC_ORDER + 1)], 234 &signal_out[FRAMESAMPLES_HALF]); 235 236 return len; 237 } 238 239 /* 240 * This decode function is called when the codec operates at 0-12 kHz 241 * bandwidth to decode the upperband, i.e. 8-12 kHz. 242 * 243 * At the encoder the upper-band is split into two band, 8-12 kHz & 12-16 244 * kHz, and only 8-12 kHz is encoded. At the decoder, 8-12 kHz band is 245 * reconstructed and 12-16 kHz replaced with zeros. Then two bands 246 * are combined, to reconstruct the upperband 8-16 kHz. 247 */ 248 int WebRtcIsac_DecodeUb12(float* signal_out, ISACUBDecStruct* ISACdecUB_obj, 249 WebRtc_Word16 isRCUPayload) { 250 int len, err; 251 252 float LP_dec_float[FRAMESAMPLES_HALF]; 253 float HP_dec_float[FRAMESAMPLES_HALF]; 254 255 double LPw[FRAMESAMPLES_HALF]; 256 double HPw[FRAMESAMPLES_HALF]; 257 258 double percepFilterParam[(UB_LPC_ORDER + 1)*SUBFRAMES]; 259 260 double real_f[FRAMESAMPLES_HALF]; 261 double imag_f[FRAMESAMPLES_HALF]; 262 const WebRtc_Word16 kAveragePitchGain = 0; /* No pitch-gain for upper-band. */ 263 len = 0; 264 265 /* Decode & dequantize filter coefficients. */ 266 err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj, 267 percepFilterParam, isac12kHz); 268 if (err < 0) { 269 return err; 270 } 271 272 /* Decode & de-quantize spectrum. */ 273 len = WebRtcIsac_DecodeSpec(&ISACdecUB_obj->bitstr_obj, kAveragePitchGain, 274 kIsacUpperBand12, real_f, imag_f); 275 if (len < 0) { 276 return len; 277 } 278 279 if (isRCUPayload) { 280 int n; 281 for (n = 0; n < 240; n++) { 282 real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 283 imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE; 284 } 285 } 286 /* Inverse transform. */ 287 WebRtcIsac_Spec2time(real_f, imag_f, LPw, HPw, &ISACdecUB_obj->fftstr_obj); 288 /* perceptual post-filtering (using normalized lattice filter) */ 289 WebRtcIsac_NormLatticeFilterAr(UB_LPC_ORDER, 290 ISACdecUB_obj->maskfiltstr_obj.PostStateLoF, 291 (ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, 292 LPw, percepFilterParam, LP_dec_float); 293 /* Zero for 12-16 kHz. */ 294 memset(HP_dec_float, 0, sizeof(float) * (FRAMESAMPLES_HALF)); 295 /* Recombine the 2 bands. */ 296 WebRtcIsac_FilterAndCombineFloat(HP_dec_float, LP_dec_float, signal_out, 297 &ISACdecUB_obj->postfiltbankstr_obj); 298 return len; 299 } 300
