| 1 | /* |
| 2 | * QCELP decoder |
| 3 | * Copyright (c) 2007 Reynaldo H. Verdejo Pinochet |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | /** |
| 23 | * @file |
| 24 | * QCELP decoder |
| 25 | * @author Reynaldo H. Verdejo Pinochet |
| 26 | * @remark FFmpeg merging spearheaded by Kenan Gillet |
| 27 | * @remark Development mentored by Benjamin Larson |
| 28 | */ |
| 29 | |
| 30 | #include <stddef.h> |
| 31 | |
| 32 | #include "libavutil/avassert.h" |
| 33 | #include "libavutil/channel_layout.h" |
| 34 | #include "libavutil/float_dsp.h" |
| 35 | #include "avcodec.h" |
| 36 | #include "internal.h" |
| 37 | #include "get_bits.h" |
| 38 | #include "qcelpdata.h" |
| 39 | #include "celp_filters.h" |
| 40 | #include "acelp_filters.h" |
| 41 | #include "acelp_vectors.h" |
| 42 | #include "lsp.h" |
| 43 | |
| 44 | typedef enum { |
| 45 | I_F_Q = -1, /**< insufficient frame quality */ |
| 46 | SILENCE, |
| 47 | RATE_OCTAVE, |
| 48 | RATE_QUARTER, |
| 49 | RATE_HALF, |
| 50 | RATE_FULL |
| 51 | } qcelp_packet_rate; |
| 52 | |
| 53 | typedef struct { |
| 54 | GetBitContext gb; |
| 55 | qcelp_packet_rate bitrate; |
| 56 | QCELPFrame frame; /**< unpacked data frame */ |
| 57 | |
| 58 | uint8_t erasure_count; |
| 59 | uint8_t octave_count; /**< count the consecutive RATE_OCTAVE frames */ |
| 60 | float prev_lspf[10]; |
| 61 | float predictor_lspf[10];/**< LSP predictor for RATE_OCTAVE and I_F_Q */ |
| 62 | float pitch_synthesis_filter_mem[303]; |
| 63 | float pitch_pre_filter_mem[303]; |
| 64 | float rnd_fir_filter_mem[180]; |
| 65 | float formant_mem[170]; |
| 66 | float last_codebook_gain; |
| 67 | int prev_g1[2]; |
| 68 | int prev_bitrate; |
| 69 | float pitch_gain[4]; |
| 70 | uint8_t pitch_lag[4]; |
| 71 | uint16_t first16bits; |
| 72 | uint8_t warned_buf_mismatch_bitrate; |
| 73 | |
| 74 | /* postfilter */ |
| 75 | float postfilter_synth_mem[10]; |
| 76 | float postfilter_agc_mem; |
| 77 | float postfilter_tilt_mem; |
| 78 | } QCELPContext; |
| 79 | |
| 80 | /** |
| 81 | * Initialize the speech codec according to the specification. |
| 82 | * |
| 83 | * TIA/EIA/IS-733 2.4.9 |
| 84 | */ |
| 85 | static av_cold int qcelp_decode_init(AVCodecContext *avctx) |
| 86 | { |
| 87 | QCELPContext *q = avctx->priv_data; |
| 88 | int i; |
| 89 | |
| 90 | avctx->channels = 1; |
| 91 | avctx->channel_layout = AV_CH_LAYOUT_MONO; |
| 92 | avctx->sample_fmt = AV_SAMPLE_FMT_FLT; |
| 93 | |
| 94 | for (i = 0; i < 10; i++) |
| 95 | q->prev_lspf[i] = (i + 1) / 11.0; |
| 96 | |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Decode the 10 quantized LSP frequencies from the LSPV/LSP |
| 102 | * transmission codes of any bitrate and check for badly received packets. |
| 103 | * |
| 104 | * @param q the context |
| 105 | * @param lspf line spectral pair frequencies |
| 106 | * |
| 107 | * @return 0 on success, -1 if the packet is badly received |
| 108 | * |
| 109 | * TIA/EIA/IS-733 2.4.3.2.6.2-2, 2.4.8.7.3 |
| 110 | */ |
| 111 | static int decode_lspf(QCELPContext *q, float *lspf) |
| 112 | { |
| 113 | int i; |
| 114 | float tmp_lspf, smooth, erasure_coeff; |
| 115 | const float *predictors; |
| 116 | |
| 117 | if (q->bitrate == RATE_OCTAVE || q->bitrate == I_F_Q) { |
| 118 | predictors = q->prev_bitrate != RATE_OCTAVE && |
| 119 | q->prev_bitrate != I_F_Q ? q->prev_lspf |
| 120 | : q->predictor_lspf; |
| 121 | |
| 122 | if (q->bitrate == RATE_OCTAVE) { |
| 123 | q->octave_count++; |
| 124 | |
| 125 | for (i = 0; i < 10; i++) { |
| 126 | q->predictor_lspf[i] = |
| 127 | lspf[i] = (q->frame.lspv[i] ? QCELP_LSP_SPREAD_FACTOR |
| 128 | : -QCELP_LSP_SPREAD_FACTOR) + |
| 129 | predictors[i] * QCELP_LSP_OCTAVE_PREDICTOR + |
| 130 | (i + 1) * ((1 - QCELP_LSP_OCTAVE_PREDICTOR) / 11); |
| 131 | } |
| 132 | smooth = q->octave_count < 10 ? .875 : 0.1; |
| 133 | } else { |
| 134 | erasure_coeff = QCELP_LSP_OCTAVE_PREDICTOR; |
| 135 | |
| 136 | av_assert2(q->bitrate == I_F_Q); |
| 137 | |
| 138 | if (q->erasure_count > 1) |
| 139 | erasure_coeff *= q->erasure_count < 4 ? 0.9 : 0.7; |
| 140 | |
| 141 | for (i = 0; i < 10; i++) { |
| 142 | q->predictor_lspf[i] = |
| 143 | lspf[i] = (i + 1) * (1 - erasure_coeff) / 11 + |
| 144 | erasure_coeff * predictors[i]; |
| 145 | } |
| 146 | smooth = 0.125; |
| 147 | } |
| 148 | |
| 149 | // Check the stability of the LSP frequencies. |
| 150 | lspf[0] = FFMAX(lspf[0], QCELP_LSP_SPREAD_FACTOR); |
| 151 | for (i = 1; i < 10; i++) |
| 152 | lspf[i] = FFMAX(lspf[i], lspf[i - 1] + QCELP_LSP_SPREAD_FACTOR); |
| 153 | |
| 154 | lspf[9] = FFMIN(lspf[9], 1.0 - QCELP_LSP_SPREAD_FACTOR); |
| 155 | for (i = 9; i > 0; i--) |
| 156 | lspf[i - 1] = FFMIN(lspf[i - 1], lspf[i] - QCELP_LSP_SPREAD_FACTOR); |
| 157 | |
| 158 | // Low-pass filter the LSP frequencies. |
| 159 | ff_weighted_vector_sumf(lspf, lspf, q->prev_lspf, smooth, 1.0 - smooth, 10); |
| 160 | } else { |
| 161 | q->octave_count = 0; |
| 162 | |
| 163 | tmp_lspf = 0.0; |
| 164 | for (i = 0; i < 5; i++) { |
| 165 | lspf[2 * i + 0] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][0] * 0.0001; |
| 166 | lspf[2 * i + 1] = tmp_lspf += qcelp_lspvq[i][q->frame.lspv[i]][1] * 0.0001; |
| 167 | } |
| 168 | |
| 169 | // Check for badly received packets. |
| 170 | if (q->bitrate == RATE_QUARTER) { |
| 171 | if (lspf[9] <= .70 || lspf[9] >= .97) |
| 172 | return -1; |
| 173 | for (i = 3; i < 10; i++) |
| 174 | if (fabs(lspf[i] - lspf[i - 2]) < .08) |
| 175 | return -1; |
| 176 | } else { |
| 177 | if (lspf[9] <= .66 || lspf[9] >= .985) |
| 178 | return -1; |
| 179 | for (i = 4; i < 10; i++) |
| 180 | if (fabs(lspf[i] - lspf[i - 4]) < .0931) |
| 181 | return -1; |
| 182 | } |
| 183 | } |
| 184 | return 0; |
| 185 | } |
| 186 | |
| 187 | /** |
| 188 | * Convert codebook transmission codes to GAIN and INDEX. |
| 189 | * |
| 190 | * @param q the context |
| 191 | * @param gain array holding the decoded gain |
| 192 | * |
| 193 | * TIA/EIA/IS-733 2.4.6.2 |
| 194 | */ |
| 195 | static void decode_gain_and_index(QCELPContext *q, float *gain) |
| 196 | { |
| 197 | int i, subframes_count, g1[16]; |
| 198 | float slope; |
| 199 | |
| 200 | if (q->bitrate >= RATE_QUARTER) { |
| 201 | switch (q->bitrate) { |
| 202 | case RATE_FULL: subframes_count = 16; break; |
| 203 | case RATE_HALF: subframes_count = 4; break; |
| 204 | default: subframes_count = 5; |
| 205 | } |
| 206 | for (i = 0; i < subframes_count; i++) { |
| 207 | g1[i] = 4 * q->frame.cbgain[i]; |
| 208 | if (q->bitrate == RATE_FULL && !((i + 1) & 3)) { |
| 209 | g1[i] += av_clip((g1[i - 1] + g1[i - 2] + g1[i - 3]) / 3 - 6, 0, 32); |
| 210 | } |
| 211 | |
| 212 | gain[i] = qcelp_g12ga[g1[i]]; |
| 213 | |
| 214 | if (q->frame.cbsign[i]) { |
| 215 | gain[i] = -gain[i]; |
| 216 | q->frame.cindex[i] = (q->frame.cindex[i] - 89) & 127; |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | q->prev_g1[0] = g1[i - 2]; |
| 221 | q->prev_g1[1] = g1[i - 1]; |
| 222 | q->last_codebook_gain = qcelp_g12ga[g1[i - 1]]; |
| 223 | |
| 224 | if (q->bitrate == RATE_QUARTER) { |
| 225 | // Provide smoothing of the unvoiced excitation energy. |
| 226 | gain[7] = gain[4]; |
| 227 | gain[6] = 0.4 * gain[3] + 0.6 * gain[4]; |
| 228 | gain[5] = gain[3]; |
| 229 | gain[4] = 0.8 * gain[2] + 0.2 * gain[3]; |
| 230 | gain[3] = 0.2 * gain[1] + 0.8 * gain[2]; |
| 231 | gain[2] = gain[1]; |
| 232 | gain[1] = 0.6 * gain[0] + 0.4 * gain[1]; |
| 233 | } |
| 234 | } else if (q->bitrate != SILENCE) { |
| 235 | if (q->bitrate == RATE_OCTAVE) { |
| 236 | g1[0] = 2 * q->frame.cbgain[0] + |
| 237 | av_clip((q->prev_g1[0] + q->prev_g1[1]) / 2 - 5, 0, 54); |
| 238 | subframes_count = 8; |
| 239 | } else { |
| 240 | av_assert2(q->bitrate == I_F_Q); |
| 241 | |
| 242 | g1[0] = q->prev_g1[1]; |
| 243 | switch (q->erasure_count) { |
| 244 | case 1 : break; |
| 245 | case 2 : g1[0] -= 1; break; |
| 246 | case 3 : g1[0] -= 2; break; |
| 247 | default: g1[0] -= 6; |
| 248 | } |
| 249 | if (g1[0] < 0) |
| 250 | g1[0] = 0; |
| 251 | subframes_count = 4; |
| 252 | } |
| 253 | // This interpolation is done to produce smoother background noise. |
| 254 | slope = 0.5 * (qcelp_g12ga[g1[0]] - q->last_codebook_gain) / subframes_count; |
| 255 | for (i = 1; i <= subframes_count; i++) |
| 256 | gain[i - 1] = q->last_codebook_gain + slope * i; |
| 257 | |
| 258 | q->last_codebook_gain = gain[i - 2]; |
| 259 | q->prev_g1[0] = q->prev_g1[1]; |
| 260 | q->prev_g1[1] = g1[0]; |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | /** |
| 265 | * If the received packet is Rate 1/4 a further sanity check is made of the |
| 266 | * codebook gain. |
| 267 | * |
| 268 | * @param cbgain the unpacked cbgain array |
| 269 | * @return -1 if the sanity check fails, 0 otherwise |
| 270 | * |
| 271 | * TIA/EIA/IS-733 2.4.8.7.3 |
| 272 | */ |
| 273 | static int codebook_sanity_check_for_rate_quarter(const uint8_t *cbgain) |
| 274 | { |
| 275 | int i, diff, prev_diff = 0; |
| 276 | |
| 277 | for (i = 1; i < 5; i++) { |
| 278 | diff = cbgain[i] - cbgain[i-1]; |
| 279 | if (FFABS(diff) > 10) |
| 280 | return -1; |
| 281 | else if (FFABS(diff - prev_diff) > 12) |
| 282 | return -1; |
| 283 | prev_diff = diff; |
| 284 | } |
| 285 | return 0; |
| 286 | } |
| 287 | |
| 288 | /** |
| 289 | * Compute the scaled codebook vector Cdn From INDEX and GAIN |
| 290 | * for all rates. |
| 291 | * |
| 292 | * The specification lacks some information here. |
| 293 | * |
| 294 | * TIA/EIA/IS-733 has an omission on the codebook index determination |
| 295 | * formula for RATE_FULL and RATE_HALF frames at section 2.4.8.1.1. It says |
| 296 | * you have to subtract the decoded index parameter from the given scaled |
| 297 | * codebook vector index 'n' to get the desired circular codebook index, but |
| 298 | * it does not mention that you have to clamp 'n' to [0-9] in order to get |
| 299 | * RI-compliant results. |
| 300 | * |
| 301 | * The reason for this mistake seems to be the fact they forgot to mention you |
| 302 | * have to do these calculations per codebook subframe and adjust given |
| 303 | * equation values accordingly. |
| 304 | * |
| 305 | * @param q the context |
| 306 | * @param gain array holding the 4 pitch subframe gain values |
| 307 | * @param cdn_vector array for the generated scaled codebook vector |
| 308 | */ |
| 309 | static void compute_svector(QCELPContext *q, const float *gain, |
| 310 | float *cdn_vector) |
| 311 | { |
| 312 | int i, j, k; |
| 313 | uint16_t cbseed, cindex; |
| 314 | float *rnd, tmp_gain, fir_filter_value; |
| 315 | |
| 316 | switch (q->bitrate) { |
| 317 | case RATE_FULL: |
| 318 | for (i = 0; i < 16; i++) { |
| 319 | tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO; |
| 320 | cindex = -q->frame.cindex[i]; |
| 321 | for (j = 0; j < 10; j++) |
| 322 | *cdn_vector++ = tmp_gain * |
| 323 | qcelp_rate_full_codebook[cindex++ & 127]; |
| 324 | } |
| 325 | break; |
| 326 | case RATE_HALF: |
| 327 | for (i = 0; i < 4; i++) { |
| 328 | tmp_gain = gain[i] * QCELP_RATE_HALF_CODEBOOK_RATIO; |
| 329 | cindex = -q->frame.cindex[i]; |
| 330 | for (j = 0; j < 40; j++) |
| 331 | *cdn_vector++ = tmp_gain * |
| 332 | qcelp_rate_half_codebook[cindex++ & 127]; |
| 333 | } |
| 334 | break; |
| 335 | case RATE_QUARTER: |
| 336 | cbseed = (0x0003 & q->frame.lspv[4]) << 14 | |
| 337 | (0x003F & q->frame.lspv[3]) << 8 | |
| 338 | (0x0060 & q->frame.lspv[2]) << 1 | |
| 339 | (0x0007 & q->frame.lspv[1]) << 3 | |
| 340 | (0x0038 & q->frame.lspv[0]) >> 3; |
| 341 | rnd = q->rnd_fir_filter_mem + 20; |
| 342 | for (i = 0; i < 8; i++) { |
| 343 | tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0); |
| 344 | for (k = 0; k < 20; k++) { |
| 345 | cbseed = 521 * cbseed + 259; |
| 346 | *rnd = (int16_t) cbseed; |
| 347 | |
| 348 | // FIR filter |
| 349 | fir_filter_value = 0.0; |
| 350 | for (j = 0; j < 10; j++) |
| 351 | fir_filter_value += qcelp_rnd_fir_coefs[j] * |
| 352 | (rnd[-j] + rnd[-20+j]); |
| 353 | |
| 354 | fir_filter_value += qcelp_rnd_fir_coefs[10] * rnd[-10]; |
| 355 | *cdn_vector++ = tmp_gain * fir_filter_value; |
| 356 | rnd++; |
| 357 | } |
| 358 | } |
| 359 | memcpy(q->rnd_fir_filter_mem, q->rnd_fir_filter_mem + 160, |
| 360 | 20 * sizeof(float)); |
| 361 | break; |
| 362 | case RATE_OCTAVE: |
| 363 | cbseed = q->first16bits; |
| 364 | for (i = 0; i < 8; i++) { |
| 365 | tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0); |
| 366 | for (j = 0; j < 20; j++) { |
| 367 | cbseed = 521 * cbseed + 259; |
| 368 | *cdn_vector++ = tmp_gain * (int16_t) cbseed; |
| 369 | } |
| 370 | } |
| 371 | break; |
| 372 | case I_F_Q: |
| 373 | cbseed = -44; // random codebook index |
| 374 | for (i = 0; i < 4; i++) { |
| 375 | tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO; |
| 376 | for (j = 0; j < 40; j++) |
| 377 | *cdn_vector++ = tmp_gain * |
| 378 | qcelp_rate_full_codebook[cbseed++ & 127]; |
| 379 | } |
| 380 | break; |
| 381 | case SILENCE: |
| 382 | memset(cdn_vector, 0, 160 * sizeof(float)); |
| 383 | break; |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | /** |
| 388 | * Apply generic gain control. |
| 389 | * |
| 390 | * @param v_out output vector |
| 391 | * @param v_in gain-controlled vector |
| 392 | * @param v_ref vector to control gain of |
| 393 | * |
| 394 | * TIA/EIA/IS-733 2.4.8.3, 2.4.8.6 |
| 395 | */ |
| 396 | static void apply_gain_ctrl(float *v_out, const float *v_ref, const float *v_in) |
| 397 | { |
| 398 | int i; |
| 399 | |
| 400 | for (i = 0; i < 160; i += 40) { |
| 401 | float res = avpriv_scalarproduct_float_c(v_ref + i, v_ref + i, 40); |
| 402 | ff_scale_vector_to_given_sum_of_squares(v_out + i, v_in + i, res, 40); |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | /** |
| 407 | * Apply filter in pitch-subframe steps. |
| 408 | * |
| 409 | * @param memory buffer for the previous state of the filter |
| 410 | * - must be able to contain 303 elements |
| 411 | * - the 143 first elements are from the previous state |
| 412 | * - the next 160 are for output |
| 413 | * @param v_in input filter vector |
| 414 | * @param gain per-subframe gain array, each element is between 0.0 and 2.0 |
| 415 | * @param lag per-subframe lag array, each element is |
| 416 | * - between 16 and 143 if its corresponding pfrac is 0, |
| 417 | * - between 16 and 139 otherwise |
| 418 | * @param pfrac per-subframe boolean array, 1 if the lag is fractional, 0 |
| 419 | * otherwise |
| 420 | * |
| 421 | * @return filter output vector |
| 422 | */ |
| 423 | static const float *do_pitchfilter(float memory[303], const float v_in[160], |
| 424 | const float gain[4], const uint8_t *lag, |
| 425 | const uint8_t pfrac[4]) |
| 426 | { |
| 427 | int i, j; |
| 428 | float *v_lag, *v_out; |
| 429 | const float *v_len; |
| 430 | |
| 431 | v_out = memory + 143; // Output vector starts at memory[143]. |
| 432 | |
| 433 | for (i = 0; i < 4; i++) { |
| 434 | if (gain[i]) { |
| 435 | v_lag = memory + 143 + 40 * i - lag[i]; |
| 436 | for (v_len = v_in + 40; v_in < v_len; v_in++) { |
| 437 | if (pfrac[i]) { // If it is a fractional lag... |
| 438 | for (j = 0, *v_out = 0.0; j < 4; j++) |
| 439 | *v_out += qcelp_hammsinc_table[j] * |
| 440 | (v_lag[j - 4] + v_lag[3 - j]); |
| 441 | } else |
| 442 | *v_out = *v_lag; |
| 443 | |
| 444 | *v_out = *v_in + gain[i] * *v_out; |
| 445 | |
| 446 | v_lag++; |
| 447 | v_out++; |
| 448 | } |
| 449 | } else { |
| 450 | memcpy(v_out, v_in, 40 * sizeof(float)); |
| 451 | v_in += 40; |
| 452 | v_out += 40; |
| 453 | } |
| 454 | } |
| 455 | |
| 456 | memmove(memory, memory + 160, 143 * sizeof(float)); |
| 457 | return memory + 143; |
| 458 | } |
| 459 | |
| 460 | /** |
| 461 | * Apply pitch synthesis filter and pitch prefilter to the scaled codebook vector. |
| 462 | * TIA/EIA/IS-733 2.4.5.2, 2.4.8.7.2 |
| 463 | * |
| 464 | * @param q the context |
| 465 | * @param cdn_vector the scaled codebook vector |
| 466 | */ |
| 467 | static void apply_pitch_filters(QCELPContext *q, float *cdn_vector) |
| 468 | { |
| 469 | int i; |
| 470 | const float *v_synthesis_filtered, *v_pre_filtered; |
| 471 | |
| 472 | if (q->bitrate >= RATE_HALF || q->bitrate == SILENCE || |
| 473 | (q->bitrate == I_F_Q && (q->prev_bitrate >= RATE_HALF))) { |
| 474 | |
| 475 | if (q->bitrate >= RATE_HALF) { |
| 476 | // Compute gain & lag for the whole frame. |
| 477 | for (i = 0; i < 4; i++) { |
| 478 | q->pitch_gain[i] = q->frame.plag[i] ? (q->frame.pgain[i] + 1) * 0.25 : 0.0; |
| 479 | |
| 480 | q->pitch_lag[i] = q->frame.plag[i] + 16; |
| 481 | } |
| 482 | } else { |
| 483 | float max_pitch_gain; |
| 484 | |
| 485 | if (q->bitrate == I_F_Q) { |
| 486 | if (q->erasure_count < 3) |
| 487 | max_pitch_gain = 0.9 - 0.3 * (q->erasure_count - 1); |
| 488 | else |
| 489 | max_pitch_gain = 0.0; |
| 490 | } else { |
| 491 | av_assert2(q->bitrate == SILENCE); |
| 492 | max_pitch_gain = 1.0; |
| 493 | } |
| 494 | for (i = 0; i < 4; i++) |
| 495 | q->pitch_gain[i] = FFMIN(q->pitch_gain[i], max_pitch_gain); |
| 496 | |
| 497 | memset(q->frame.pfrac, 0, sizeof(q->frame.pfrac)); |
| 498 | } |
| 499 | |
| 500 | // pitch synthesis filter |
| 501 | v_synthesis_filtered = do_pitchfilter(q->pitch_synthesis_filter_mem, |
| 502 | cdn_vector, q->pitch_gain, |
| 503 | q->pitch_lag, q->frame.pfrac); |
| 504 | |
| 505 | // pitch prefilter update |
| 506 | for (i = 0; i < 4; i++) |
| 507 | q->pitch_gain[i] = 0.5 * FFMIN(q->pitch_gain[i], 1.0); |
| 508 | |
| 509 | v_pre_filtered = do_pitchfilter(q->pitch_pre_filter_mem, |
| 510 | v_synthesis_filtered, |
| 511 | q->pitch_gain, q->pitch_lag, |
| 512 | q->frame.pfrac); |
| 513 | |
| 514 | apply_gain_ctrl(cdn_vector, v_synthesis_filtered, v_pre_filtered); |
| 515 | } else { |
| 516 | memcpy(q->pitch_synthesis_filter_mem, |
| 517 | cdn_vector + 17, 143 * sizeof(float)); |
| 518 | memcpy(q->pitch_pre_filter_mem, cdn_vector + 17, 143 * sizeof(float)); |
| 519 | memset(q->pitch_gain, 0, sizeof(q->pitch_gain)); |
| 520 | memset(q->pitch_lag, 0, sizeof(q->pitch_lag)); |
| 521 | } |
| 522 | } |
| 523 | |
| 524 | /** |
| 525 | * Reconstruct LPC coefficients from the line spectral pair frequencies |
| 526 | * and perform bandwidth expansion. |
| 527 | * |
| 528 | * @param lspf line spectral pair frequencies |
| 529 | * @param lpc linear predictive coding coefficients |
| 530 | * |
| 531 | * @note: bandwidth_expansion_coeff could be precalculated into a table |
| 532 | * but it seems to be slower on x86 |
| 533 | * |
| 534 | * TIA/EIA/IS-733 2.4.3.3.5 |
| 535 | */ |
| 536 | static void lspf2lpc(const float *lspf, float *lpc) |
| 537 | { |
| 538 | double lsp[10]; |
| 539 | double bandwidth_expansion_coeff = QCELP_BANDWIDTH_EXPANSION_COEFF; |
| 540 | int i; |
| 541 | |
| 542 | for (i = 0; i < 10; i++) |
| 543 | lsp[i] = cos(M_PI * lspf[i]); |
| 544 | |
| 545 | ff_acelp_lspd2lpc(lsp, lpc, 5); |
| 546 | |
| 547 | for (i = 0; i < 10; i++) { |
| 548 | lpc[i] *= bandwidth_expansion_coeff; |
| 549 | bandwidth_expansion_coeff *= QCELP_BANDWIDTH_EXPANSION_COEFF; |
| 550 | } |
| 551 | } |
| 552 | |
| 553 | /** |
| 554 | * Interpolate LSP frequencies and compute LPC coefficients |
| 555 | * for a given bitrate & pitch subframe. |
| 556 | * |
| 557 | * TIA/EIA/IS-733 2.4.3.3.4, 2.4.8.7.2 |
| 558 | * |
| 559 | * @param q the context |
| 560 | * @param curr_lspf LSP frequencies vector of the current frame |
| 561 | * @param lpc float vector for the resulting LPC |
| 562 | * @param subframe_num frame number in decoded stream |
| 563 | */ |
| 564 | static void interpolate_lpc(QCELPContext *q, const float *curr_lspf, |
| 565 | float *lpc, const int subframe_num) |
| 566 | { |
| 567 | float interpolated_lspf[10]; |
| 568 | float weight; |
| 569 | |
| 570 | if (q->bitrate >= RATE_QUARTER) |
| 571 | weight = 0.25 * (subframe_num + 1); |
| 572 | else if (q->bitrate == RATE_OCTAVE && !subframe_num) |
| 573 | weight = 0.625; |
| 574 | else |
| 575 | weight = 1.0; |
| 576 | |
| 577 | if (weight != 1.0) { |
| 578 | ff_weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf, |
| 579 | weight, 1.0 - weight, 10); |
| 580 | lspf2lpc(interpolated_lspf, lpc); |
| 581 | } else if (q->bitrate >= RATE_QUARTER || |
| 582 | (q->bitrate == I_F_Q && !subframe_num)) |
| 583 | lspf2lpc(curr_lspf, lpc); |
| 584 | else if (q->bitrate == SILENCE && !subframe_num) |
| 585 | lspf2lpc(q->prev_lspf, lpc); |
| 586 | } |
| 587 | |
| 588 | static qcelp_packet_rate buf_size2bitrate(const int buf_size) |
| 589 | { |
| 590 | switch (buf_size) { |
| 591 | case 35: return RATE_FULL; |
| 592 | case 17: return RATE_HALF; |
| 593 | case 8: return RATE_QUARTER; |
| 594 | case 4: return RATE_OCTAVE; |
| 595 | case 1: return SILENCE; |
| 596 | } |
| 597 | |
| 598 | return I_F_Q; |
| 599 | } |
| 600 | |
| 601 | /** |
| 602 | * Determine the bitrate from the frame size and/or the first byte of the frame. |
| 603 | * |
| 604 | * @param avctx the AV codec context |
| 605 | * @param buf_size length of the buffer |
| 606 | * @param buf the bufffer |
| 607 | * |
| 608 | * @return the bitrate on success, |
| 609 | * I_F_Q if the bitrate cannot be satisfactorily determined |
| 610 | * |
| 611 | * TIA/EIA/IS-733 2.4.8.7.1 |
| 612 | */ |
| 613 | static qcelp_packet_rate determine_bitrate(AVCodecContext *avctx, |
| 614 | const int buf_size, |
| 615 | const uint8_t **buf) |
| 616 | { |
| 617 | qcelp_packet_rate bitrate; |
| 618 | |
| 619 | if ((bitrate = buf_size2bitrate(buf_size)) >= 0) { |
| 620 | if (bitrate > **buf) { |
| 621 | QCELPContext *q = avctx->priv_data; |
| 622 | if (!q->warned_buf_mismatch_bitrate) { |
| 623 | av_log(avctx, AV_LOG_WARNING, |
| 624 | "Claimed bitrate and buffer size mismatch.\n"); |
| 625 | q->warned_buf_mismatch_bitrate = 1; |
| 626 | } |
| 627 | bitrate = **buf; |
| 628 | } else if (bitrate < **buf) { |
| 629 | av_log(avctx, AV_LOG_ERROR, |
| 630 | "Buffer is too small for the claimed bitrate.\n"); |
| 631 | return I_F_Q; |
| 632 | } |
| 633 | (*buf)++; |
| 634 | } else if ((bitrate = buf_size2bitrate(buf_size + 1)) >= 0) { |
| 635 | av_log(avctx, AV_LOG_WARNING, |
| 636 | "Bitrate byte missing, guessing bitrate from packet size.\n"); |
| 637 | } else |
| 638 | return I_F_Q; |
| 639 | |
| 640 | if (bitrate == SILENCE) { |
| 641 | // FIXME: Remove this warning when tested with samples. |
| 642 | avpriv_request_sample(avctx, "Blank frame handling"); |
| 643 | } |
| 644 | return bitrate; |
| 645 | } |
| 646 | |
| 647 | static void warn_insufficient_frame_quality(AVCodecContext *avctx, |
| 648 | const char *message) |
| 649 | { |
| 650 | av_log(avctx, AV_LOG_WARNING, "Frame #%d, IFQ: %s\n", |
| 651 | avctx->frame_number, message); |
| 652 | } |
| 653 | |
| 654 | static void postfilter(QCELPContext *q, float *samples, float *lpc) |
| 655 | { |
| 656 | static const float pow_0_775[10] = { |
| 657 | 0.775000, 0.600625, 0.465484, 0.360750, 0.279582, |
| 658 | 0.216676, 0.167924, 0.130141, 0.100859, 0.078166 |
| 659 | }, pow_0_625[10] = { |
| 660 | 0.625000, 0.390625, 0.244141, 0.152588, 0.095367, |
| 661 | 0.059605, 0.037253, 0.023283, 0.014552, 0.009095 |
| 662 | }; |
| 663 | float lpc_s[10], lpc_p[10], pole_out[170], zero_out[160]; |
| 664 | int n; |
| 665 | |
| 666 | for (n = 0; n < 10; n++) { |
| 667 | lpc_s[n] = lpc[n] * pow_0_625[n]; |
| 668 | lpc_p[n] = lpc[n] * pow_0_775[n]; |
| 669 | } |
| 670 | |
| 671 | ff_celp_lp_zero_synthesis_filterf(zero_out, lpc_s, |
| 672 | q->formant_mem + 10, 160, 10); |
| 673 | memcpy(pole_out, q->postfilter_synth_mem, sizeof(float) * 10); |
| 674 | ff_celp_lp_synthesis_filterf(pole_out + 10, lpc_p, zero_out, 160, 10); |
| 675 | memcpy(q->postfilter_synth_mem, pole_out + 160, sizeof(float) * 10); |
| 676 | |
| 677 | ff_tilt_compensation(&q->postfilter_tilt_mem, 0.3, pole_out + 10, 160); |
| 678 | |
| 679 | ff_adaptive_gain_control(samples, pole_out + 10, |
| 680 | avpriv_scalarproduct_float_c(q->formant_mem + 10, |
| 681 | q->formant_mem + 10, |
| 682 | 160), |
| 683 | 160, 0.9375, &q->postfilter_agc_mem); |
| 684 | } |
| 685 | |
| 686 | static int qcelp_decode_frame(AVCodecContext *avctx, void *data, |
| 687 | int *got_frame_ptr, AVPacket *avpkt) |
| 688 | { |
| 689 | const uint8_t *buf = avpkt->data; |
| 690 | int buf_size = avpkt->size; |
| 691 | QCELPContext *q = avctx->priv_data; |
| 692 | AVFrame *frame = data; |
| 693 | float *outbuffer; |
| 694 | int i, ret; |
| 695 | float quantized_lspf[10], lpc[10]; |
| 696 | float gain[16]; |
| 697 | float *formant_mem; |
| 698 | |
| 699 | /* get output buffer */ |
| 700 | frame->nb_samples = 160; |
| 701 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 702 | return ret; |
| 703 | outbuffer = (float *)frame->data[0]; |
| 704 | |
| 705 | if ((q->bitrate = determine_bitrate(avctx, buf_size, &buf)) == I_F_Q) { |
| 706 | warn_insufficient_frame_quality(avctx, "Bitrate cannot be determined."); |
| 707 | goto erasure; |
| 708 | } |
| 709 | |
| 710 | if (q->bitrate == RATE_OCTAVE && |
| 711 | (q->first16bits = AV_RB16(buf)) == 0xFFFF) { |
| 712 | warn_insufficient_frame_quality(avctx, "Bitrate is 1/8 and first 16 bits are on."); |
| 713 | goto erasure; |
| 714 | } |
| 715 | |
| 716 | if (q->bitrate > SILENCE) { |
| 717 | const QCELPBitmap *bitmaps = qcelp_unpacking_bitmaps_per_rate[q->bitrate]; |
| 718 | const QCELPBitmap *bitmaps_end = qcelp_unpacking_bitmaps_per_rate[q->bitrate] + |
| 719 | qcelp_unpacking_bitmaps_lengths[q->bitrate]; |
| 720 | uint8_t *unpacked_data = (uint8_t *)&q->frame; |
| 721 | |
| 722 | init_get_bits(&q->gb, buf, 8 * buf_size); |
| 723 | |
| 724 | memset(&q->frame, 0, sizeof(QCELPFrame)); |
| 725 | |
| 726 | for (; bitmaps < bitmaps_end; bitmaps++) |
| 727 | unpacked_data[bitmaps->index] |= get_bits(&q->gb, bitmaps->bitlen) << bitmaps->bitpos; |
| 728 | |
| 729 | // Check for erasures/blanks on rates 1, 1/4 and 1/8. |
| 730 | if (q->frame.reserved) { |
| 731 | warn_insufficient_frame_quality(avctx, "Wrong data in reserved frame area."); |
| 732 | goto erasure; |
| 733 | } |
| 734 | if (q->bitrate == RATE_QUARTER && |
| 735 | codebook_sanity_check_for_rate_quarter(q->frame.cbgain)) { |
| 736 | warn_insufficient_frame_quality(avctx, "Codebook gain sanity check failed."); |
| 737 | goto erasure; |
| 738 | } |
| 739 | |
| 740 | if (q->bitrate >= RATE_HALF) { |
| 741 | for (i = 0; i < 4; i++) { |
| 742 | if (q->frame.pfrac[i] && q->frame.plag[i] >= 124) { |
| 743 | warn_insufficient_frame_quality(avctx, "Cannot initialize pitch filter."); |
| 744 | goto erasure; |
| 745 | } |
| 746 | } |
| 747 | } |
| 748 | } |
| 749 | |
| 750 | decode_gain_and_index(q, gain); |
| 751 | compute_svector(q, gain, outbuffer); |
| 752 | |
| 753 | if (decode_lspf(q, quantized_lspf) < 0) { |
| 754 | warn_insufficient_frame_quality(avctx, "Badly received packets in frame."); |
| 755 | goto erasure; |
| 756 | } |
| 757 | |
| 758 | apply_pitch_filters(q, outbuffer); |
| 759 | |
| 760 | if (q->bitrate == I_F_Q) { |
| 761 | erasure: |
| 762 | q->bitrate = I_F_Q; |
| 763 | q->erasure_count++; |
| 764 | decode_gain_and_index(q, gain); |
| 765 | compute_svector(q, gain, outbuffer); |
| 766 | decode_lspf(q, quantized_lspf); |
| 767 | apply_pitch_filters(q, outbuffer); |
| 768 | } else |
| 769 | q->erasure_count = 0; |
| 770 | |
| 771 | formant_mem = q->formant_mem + 10; |
| 772 | for (i = 0; i < 4; i++) { |
| 773 | interpolate_lpc(q, quantized_lspf, lpc, i); |
| 774 | ff_celp_lp_synthesis_filterf(formant_mem, lpc, |
| 775 | outbuffer + i * 40, 40, 10); |
| 776 | formant_mem += 40; |
| 777 | } |
| 778 | |
| 779 | // postfilter, as per TIA/EIA/IS-733 2.4.8.6 |
| 780 | postfilter(q, outbuffer, lpc); |
| 781 | |
| 782 | memcpy(q->formant_mem, q->formant_mem + 160, 10 * sizeof(float)); |
| 783 | |
| 784 | memcpy(q->prev_lspf, quantized_lspf, sizeof(q->prev_lspf)); |
| 785 | q->prev_bitrate = q->bitrate; |
| 786 | |
| 787 | *got_frame_ptr = 1; |
| 788 | |
| 789 | return buf_size; |
| 790 | } |
| 791 | |
| 792 | AVCodec ff_qcelp_decoder = { |
| 793 | .name = "qcelp", |
| 794 | .long_name = NULL_IF_CONFIG_SMALL("QCELP / PureVoice"), |
| 795 | .type = AVMEDIA_TYPE_AUDIO, |
| 796 | .id = AV_CODEC_ID_QCELP, |
| 797 | .init = qcelp_decode_init, |
| 798 | .decode = qcelp_decode_frame, |
| 799 | .capabilities = CODEC_CAP_DR1, |
| 800 | .priv_data_size = sizeof(QCELPContext), |
| 801 | }; |