FFmpeg: libavcodec/evrcdec.c Source File

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evrcdec.c

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1 /*

2 * Enhanced Variable Rate Codec, Service Option 3 decoder

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 */

22 /**

23 * @file

24 * Enhanced Variable Rate Codec, Service Option 3 decoder

25 * @author Paul B Mahol

26 */

28 #include "libavutil/mathematics.h"

29 #include "avcodec.h"

30 #include "internal.h"

31 #include "get_bits.h"

32 #include "evrcdata.h"

33 #include "acelp_vectors.h"

34 #include "lsp.h"

36 #define MIN_LSP_SEP (0.05 / (2.0 * M_PI))

37 #define MIN_DELAY 20

38 #define MAX_DELAY 120

39 #define NB_SUBFRAMES 3

40 #define SUBFRAME_SIZE 54

41 #define FILTER_ORDER 10

42 #define ACB_SIZE 128

44 typedef enum {

45 RATE_ERRS = -1,

46 SILENCE,

47 RATE_QUANT,

48 RATE_QUARTER,

49 RATE_HALF,

50 RATE_FULL,

51 } evrc_packet_rate;

53 /**

54 * EVRC-A unpacked data frame

55 */

56 typedef struct EVRCAFrame {

57 uint8_t lpc_flag; ///< spectral change indicator

58 uint16_t lsp[4]; ///< index into LSP codebook

59 uint8_t pitch_delay; ///< pitch delay for entire frame

60 uint8_t delay_diff; ///< delay difference for entire frame

61 uint8_t acb_gain[3]; ///< adaptive codebook gain

62 uint16_t fcb_shape[3][4]; ///< fixed codebook shape

63 uint8_t fcb_gain[3]; ///< fixed codebook gain index

64 uint8_t energy_gain; ///< frame energy gain index

65 uint8_t tty; ///< tty baud rate bit

66 } EVRCAFrame;

68 typedef struct EVRCContext {

69 GetBitContext gb;

70 evrc_packet_rate bitrate;

71 evrc_packet_rate last_valid_bitrate;

72 EVRCAFrame frame;

74 float lspf[FILTER_ORDER];

75 float prev_lspf[FILTER_ORDER];

76 float synthesis[FILTER_ORDER];

77 float postfilter_fir[FILTER_ORDER];

78 float postfilter_iir[FILTER_ORDER];

79 float postfilter_residual[ACB_SIZE + SUBFRAME_SIZE];

80 float pitch_delay;

81 float prev_pitch_delay;

82 float avg_acb_gain; ///< average adaptive codebook gain

83 float avg_fcb_gain; ///< average fixed codebook gain

84 float pitch[ACB_SIZE + FILTER_ORDER + SUBFRAME_SIZE];

85 float pitch_back[ACB_SIZE];

86 float interpolation_coeffs[136];

87 float energy_vector[NB_SUBFRAMES];

88 float fade_scale;

89 float last;

91 uint8_t prev_energy_gain;

92 uint8_t prev_error_flag;

93 uint8_t warned_buf_mismatch_bitrate;

94 } EVRCContext;

96 /**

97 * Frame unpacking for RATE_FULL, RATE_HALF and RATE_QUANT

98 *

99 * @param e the context

100 *

101 * TIA/IS-127 Table 4.21-1

102 */

103 static void unpack_frame(EVRCContext *e)

104 {

105 EVRCAFrame *frame = &e->frame;

106 GetBitContext *gb = &e->gb;

107

108 switch (e->bitrate) {

109 case RATE_FULL:

110 frame->lpc_flag = get_bits1(gb);

111 frame->lsp[0] = get_bits(gb, 6);

112 frame->lsp[1] = get_bits(gb, 6);

113 frame->lsp[2] = get_bits(gb, 9);

114 frame->lsp[3] = get_bits(gb, 7);

115 frame->pitch_delay = get_bits(gb, 7);

116 frame->delay_diff = get_bits(gb, 5);

117 frame->acb_gain[0] = get_bits(gb, 3);

118 frame->fcb_shape[0][0] = get_bits(gb, 8);

119 frame->fcb_shape[0][1] = get_bits(gb, 8);

120 frame->fcb_shape[0][2] = get_bits(gb, 8);

121 frame->fcb_shape[0][3] = get_bits(gb, 11);

122 frame->fcb_gain[0] = get_bits(gb, 5);

123 frame->acb_gain[1] = get_bits(gb, 3);

124 frame->fcb_shape[1][0] = get_bits(gb, 8);

125 frame->fcb_shape[1][1] = get_bits(gb, 8);

126 frame->fcb_shape[1][2] = get_bits(gb, 8);

127 frame->fcb_shape[1][3] = get_bits(gb, 11);

128 frame->fcb_gain [1] = get_bits(gb, 5);

129 frame->acb_gain [2] = get_bits(gb, 3);

130 frame->fcb_shape[2][0] = get_bits(gb, 8);

131 frame->fcb_shape[2][1] = get_bits(gb, 8);

132 frame->fcb_shape[2][2] = get_bits(gb, 8);

133 frame->fcb_shape[2][3] = get_bits(gb, 11);

134 frame->fcb_gain [2] = get_bits(gb, 5);

135 frame->tty = get_bits1(gb);

136 break;

137 case RATE_HALF:

138 frame->lsp [0] = get_bits(gb, 7);

139 frame->lsp [1] = get_bits(gb, 7);

140 frame->lsp [2] = get_bits(gb, 8);

141 frame->pitch_delay = get_bits(gb, 7);

142 frame->acb_gain [0] = get_bits(gb, 3);

143 frame->fcb_shape[0][0] = get_bits(gb, 10);

144 frame->fcb_gain [0] = get_bits(gb, 4);

145 frame->acb_gain [1] = get_bits(gb, 3);

146 frame->fcb_shape[1][0] = get_bits(gb, 10);

147 frame->fcb_gain [1] = get_bits(gb, 4);

148 frame->acb_gain [2] = get_bits(gb, 3);

149 frame->fcb_shape[2][0] = get_bits(gb, 10);

150 frame->fcb_gain [2] = get_bits(gb, 4);

151 break;

152 case RATE_QUANT:

153 frame->lsp [0] = get_bits(gb, 4);

154 frame->lsp [1] = get_bits(gb, 4);

155 frame->energy_gain = get_bits(gb, 8);

156 break;

157 }

158 }

159

160 static evrc_packet_rate buf_size2bitrate(const int buf_size)

161 {

162 switch (buf_size) {

163 case 23: return RATE_FULL;

164 case 11: return RATE_HALF;

165 case 6: return RATE_QUARTER;

166 case 3: return RATE_QUANT;

167 case 1: return SILENCE;

168 }

169

170 return RATE_ERRS;

171 }

172

173 /**

174 * Determine the bitrate from the frame size and/or the first byte of the frame.

175 *

176 * @param avctx the AV codec context

177 * @param buf_size length of the buffer

178 * @param buf the bufffer

179 *

180 * @return the bitrate on success,

181 * RATE_ERRS if the bitrate cannot be satisfactorily determined

182 */

183 static evrc_packet_rate determine_bitrate(AVCodecContext *avctx,

184 int *buf_size,

185 const uint8_t **buf)

186 {

187 evrc_packet_rate bitrate;

188

189 if ((bitrate = buf_size2bitrate(*buf_size)) >= 0) {

190 if (bitrate > **buf) {

191 EVRCContext *e = avctx->priv_data;

192 if (!e->warned_buf_mismatch_bitrate) {

193 av_log(avctx, AV_LOG_WARNING,

194 "Claimed bitrate and buffer size mismatch.\n");

195 e->warned_buf_mismatch_bitrate = 1;

196 }

197 bitrate = **buf;

198 } else if (bitrate < **buf) {

199 av_log(avctx, AV_LOG_ERROR,

200 "Buffer is too small for the claimed bitrate.\n");

201 return RATE_ERRS;

202 }

203 (*buf)++;

204 *buf_size -= 1;

205 } else if ((bitrate = buf_size2bitrate(*buf_size + 1)) >= 0) {

206 av_log(avctx, AV_LOG_DEBUG,

207 "Bitrate byte is missing, guessing the bitrate from packet size.\n");

208 } else

209 return RATE_ERRS;

210

211 return bitrate;

212 }

213

214 static void warn_insufficient_frame_quality(AVCodecContext *avctx,

215 const char *message)

216 {

217 av_log(avctx, AV_LOG_WARNING, "Frame #%d, %s\n",

218 avctx->frame_number, message);

219 }

220

221 /**

222 * Initialize the speech codec according to the specification.

223 *

224 * TIA/IS-127 5.2

225 */

226 static av_cold int evrc_decode_init(AVCodecContext *avctx)

227 {

228 EVRCContext *e = avctx->priv_data;

229 int i, n, idx = 0;

230 float denom = 2.0 / (2.0 * 8.0 + 1.0);

231

232 avctx->channels = 1;

233 avctx->channel_layout = AV_CH_LAYOUT_MONO;

234 avctx->sample_fmt = AV_SAMPLE_FMT_FLT;

235

236 for (i = 0; i < FILTER_ORDER; i++) {

237 e->prev_lspf[i] = (i + 1) * 0.048;

238 e->synthesis[i] = 0.0;

239 }

240

241 for (i = 0; i < ACB_SIZE; i++)

242 e->pitch[i] = e->pitch_back[i] = 0.0;

243

244 e->last_valid_bitrate = RATE_QUANT;

245 e->prev_pitch_delay = 40.0;

246 e->fade_scale = 1.0;

247 e->prev_error_flag = 0;

248 e->avg_acb_gain = e->avg_fcb_gain = 0.0;

249

250 for (i = 0; i < 8; i++) {

251 float tt = ((float)i - 8.0 / 2.0) / 8.0;

252

253 for (n = -8; n <= 8; n++, idx++) {

254 float arg1 = M_PI * 0.9 * (tt - n);

255 float arg2 = M_PI * (tt - n);

256

257 e->interpolation_coeffs[idx] = 0.9;

258 if (arg1)

259 e->interpolation_coeffs[idx] *= (0.54 + 0.46 * cos(arg2 * denom)) *

260 sin(arg1) / arg1;

261 }

262 }

263

264 return 0;

265 }

266

267 /**

268 * Decode the 10 vector quantized line spectral pair frequencies from the LSP

269 * transmission codes of any bitrate and check for badly received packets.

270 *

271 * @param e the context

272 *

273 * @return 0 on success, -1 if the packet is badly received

274 *

275 * TIA/IS-127 5.2.1, 5.7.1

276 */

277 static int decode_lspf(EVRCContext *e)

278 {

279 const float **codebooks = evrc_lspq_codebooks[e->bitrate];

280 int i, j, k = 0;

281

282 for (i = 0; i < evrc_lspq_nb_codebooks[e->bitrate]; i++) {

283 int row_size = evrc_lspq_codebooks_row_sizes[e->bitrate][i];

284 const float *codebook = codebooks[i];

285

286 for (j = 0; j < row_size; j++)

287 e->lspf[k++] = codebook[e->frame.lsp[i] * row_size + j];

288 }

289

290 // check for monotonic LSPs

291 for (i = 1; i < FILTER_ORDER; i++)

292 if (e->lspf[i] <= e->lspf[i - 1])

293 return -1;

294

295 // check for minimum separation of LSPs at the splits

296 for (i = 0, k = 0; i < evrc_lspq_nb_codebooks[e->bitrate] - 1; i++) {

297 k += evrc_lspq_codebooks_row_sizes[e->bitrate][i];

298 if (e->lspf[k] - e->lspf[k - 1] <= MIN_LSP_SEP)

299 return -1;

300 }

301

302 return 0;

303 }

304

305 /*

306 * Interpolation of LSP parameters.

307 *

308 * TIA/IS-127 5.2.3.1, 5.7.3.2

309 */

310 static void interpolate_lsp(float *ilsp, const float *lsp,

311 const float *prev, int index)

312 {

313 static const float lsp_interpolation_factors[] = { 0.1667, 0.5, 0.8333 };

314 ff_weighted_vector_sumf(ilsp, prev, lsp,

315 1.0 - lsp_interpolation_factors[index],

316 lsp_interpolation_factors[index], FILTER_ORDER);

317 }

318

319 /*

320 * Reconstruction of the delay contour.

321 *

322 * TIA/IS-127 5.2.2.3.2

323 */

324 static void interpolate_delay(float *dst, float current, float prev, int index)

325 {

326 static const float d_interpolation_factors[] = { 0, 0.3313, 0.6625, 1, 1 };

327 dst[0] = (1.0 - d_interpolation_factors[index ]) * prev

328 + d_interpolation_factors[index ] * current;

329 dst[1] = (1.0 - d_interpolation_factors[index + 1]) * prev

330 + d_interpolation_factors[index + 1] * current;

331 dst[2] = (1.0 - d_interpolation_factors[index + 2]) * prev

332 + d_interpolation_factors[index + 2] * current;

333 }

334

335 /*

336 * Convert the quantized, interpolated line spectral frequencies,

337 * to prediction coefficients.

338 *

339 * TIA/IS-127 5.2.3.2, 4.7.2.2

340 */

341 static void decode_predictor_coeffs(const float *ilspf, float *ilpc)

342 {

343 double lsp[FILTER_ORDER];

344 float a[FILTER_ORDER / 2 + 1], b[FILTER_ORDER / 2 + 1];

345 float a1[FILTER_ORDER / 2] = { 0 };

346 float a2[FILTER_ORDER / 2] = { 0 };

347 float b1[FILTER_ORDER / 2] = { 0 };

348 float b2[FILTER_ORDER / 2] = { 0 };

349 int i, k;

350

351 ff_acelp_lsf2lspd(lsp, ilspf, FILTER_ORDER);

352

353 for (k = 0; k <= FILTER_ORDER; k++) {

354 a[0] = k < 2 ? 0.25 : 0;

355 b[0] = k < 2 ? k < 1 ? 0.25 : -0.25 : 0;

356

357 for (i = 0; i < FILTER_ORDER / 2; i++) {

358 a[i + 1] = a[i] - 2 * lsp[i * 2 ] * a1[i] + a2[i];

359 b[i + 1] = b[i] - 2 * lsp[i * 2 + 1] * b1[i] + b2[i];

360 a2[i] = a1[i];

361 a1[i] = a[i];

362 b2[i] = b1[i];

363 b1[i] = b[i];

364 }

365

366 if (k)

367 ilpc[k - 1] = 2.0 * (a[FILTER_ORDER / 2] + b[FILTER_ORDER / 2]);

368 }

369 }

370

371 static void bl_intrp(EVRCContext *e, float *ex, float delay)

372 {

373 float *f;

374 int offset, i, coef_idx;

375 int16_t t;

376

377 offset = lrintf(delay);

378

379 t = (offset - delay + 0.5) * 8.0 + 0.5;

380 if (t == 8) {

381 t = 0;

382 offset--;

383 }

384

385 f = ex - offset - 8;

386

387 coef_idx = t * (2 * 8 + 1);

388

389 ex[0] = 0.0;

390 for (i = 0; i < 2 * 8 + 1; i++)

391 ex[0] += e->interpolation_coeffs[coef_idx + i] * f[i];

392 }

393

394 /*

395 * Adaptive codebook excitation.

396 *

397 * TIA/IS-127 5.2.2.3.3, 4.12.5.2

398 */

399 static void acb_excitation(EVRCContext *e, float *excitation, float gain,

400 const float delay[3], int length)

401 {

402 float denom, locdelay, dpr, invl;

403 int i;

404

405 invl = 1.0 / ((float) length);

406 dpr = length;

407

408 /* first at-most extra samples */

409 denom = (delay[1] - delay[0]) * invl;

410 for (i = 0; i < dpr; i++) {

411 locdelay = delay[0] + i * denom;

412 bl_intrp(e, excitation + i, locdelay);

413 }

414

415 denom = (delay[2] - delay[1]) * invl;

416 /* interpolation */

417 for (i = dpr; i < dpr + 10; i++) {

418 locdelay = delay[1] + (i - dpr) * denom;

419 bl_intrp(e, excitation + i, locdelay);

420 }

421

422 for (i = 0; i < length; i++)

423 excitation[i] *= gain;

424 }

425

426 static void decode_8_pulses_35bits(const uint16_t *fixed_index, float *cod)

427 {

428 int i, pos1, pos2, offset;

429

430 offset = (fixed_index[3] >> 9) & 3;

431

432 for (i = 0; i < 3; i++) {

433 pos1 = ((fixed_index[i] & 0x7f) / 11) * 5 + ((i + offset) % 5);

434 pos2 = ((fixed_index[i] & 0x7f) % 11) * 5 + ((i + offset) % 5);

435

436 cod[pos1] = (fixed_index[i] & 0x80) ? -1.0 : 1.0;

437

438 if (pos2 < pos1)

439 cod[pos2] = -cod[pos1];

440 else

441 cod[pos2] += cod[pos1];

442 }

443

444 pos1 = ((fixed_index[3] & 0x7f) / 11) * 5 + ((3 + offset) % 5);

445 pos2 = ((fixed_index[3] & 0x7f) % 11) * 5 + ((4 + offset) % 5);

446

447 cod[pos1] = (fixed_index[3] & 0x100) ? -1.0 : 1.0;

448 cod[pos2] = (fixed_index[3] & 0x80 ) ? -1.0 : 1.0;

449 }

450

451 static void decode_3_pulses_10bits(uint16_t fixed_index, float *cod)

452 {

453 float sign;

454 int pos;

455

456 sign = (fixed_index & 0x200) ? -1.0 : 1.0;

457

458 pos = ((fixed_index & 0x7) * 7) + 4;

459 cod[pos] += sign;

460 pos = (((fixed_index >> 3) & 0x7) * 7) + 2;

461 cod[pos] -= sign;

462 pos = (((fixed_index >> 6) & 0x7) * 7);

463 cod[pos] += sign;

464 }

465

466 /*

467 * Reconstruction of ACELP fixed codebook excitation for full and half rate.

468 *

469 * TIA/IS-127 5.2.3.7

470 */

471 static void fcb_excitation(EVRCContext *e, const uint16_t *codebook,

472 float *excitation, float pitch_gain,

473 int pitch_lag, int subframe_size)

474 {

475 int i;

476

477 if (e->bitrate == RATE_FULL)

478 decode_8_pulses_35bits(codebook, excitation);

479 else

480 decode_3_pulses_10bits(*codebook, excitation);

481

482 pitch_gain = av_clipf(pitch_gain, 0.2, 0.9);

483

484 for (i = pitch_lag; i < subframe_size; i++)

485 excitation[i] += pitch_gain * excitation[i - pitch_lag];

486 }

487

488 /**

489 * Synthesis of the decoder output signal.

490 *

491 * param[in] in input signal

492 * param[in] filter_coeffs LPC coefficients

493 * param[in/out] memory synthesis filter memory

494 * param buffer_length amount of data to process

495 * param[out] samples output samples

496 *

497 * TIA/IS-127 5.2.3.15, 5.7.3.4

498 */

499 static void synthesis_filter(const float *in, const float *filter_coeffs,

500 float *memory, int buffer_length, float *samples)

501 {

502 int i, j;

503

504 for (i = 0; i < buffer_length; i++) {

505 samples[i] = in[i];

506 for (j = FILTER_ORDER - 1; j > 0; j--) {

507 samples[i] -= filter_coeffs[j] * memory[j];

508 memory[j] = memory[j - 1];

509 }

510 samples[i] -= filter_coeffs[0] * memory[0];

511 memory[0] = samples[i];

512 }

513 }

514

515 static void bandwidth_expansion(float *coeff, const float *inbuf, float gamma)

516 {

517 double fac = gamma;

518 int i;

519

520 for (i = 0; i < FILTER_ORDER; i++) {

521 coeff[i] = inbuf[i] * fac;

522 fac *= gamma;

523 }

524 }

525

526 static void residual_filter(float *output, const float *input,

527 const float *coef, float *memory, int length)

528 {

529 float sum;

530 int i, j;

531

532 for (i = 0; i < length; i++) {

533 sum = input[i];

534

535 for (j = FILTER_ORDER - 1; j > 0; j--) {

536 sum += coef[j] * memory[j];

537 memory[j] = memory[j - 1];

538 }

539 sum += coef[0] * memory[0];

540 memory[0] = input[i];

541 output[i] = sum;

542 }

543 }

544

545 /*

546 * TIA/IS-127 Table 5.9.1-1.

547 */

548 static const struct PfCoeff {

549 float tilt;

550 float ltgain;

551 float p1;

552 float p2;

553 } postfilter_coeffs[5] = {

554 { 0.0 , 0.0 , 0.0 , 0.0 },

555 { 0.0 , 0.0 , 0.57, 0.57 },

556 { 0.0 , 0.0 , 0.0 , 0.0 },

557 { 0.35, 0.50, 0.50, 0.75 },

558 { 0.20, 0.50, 0.57, 0.75 },

559 };

560

561 /*

562 * Adaptive postfilter.

563 *

564 * TIA/IS-127 5.9

565 */

566 static void postfilter(EVRCContext *e, float *in, const float *coeff,

567 float *out, int idx, const struct PfCoeff *pfc,

568 int length)

569 {

570 float wcoef1[FILTER_ORDER], wcoef2[FILTER_ORDER],

571 scratch[SUBFRAME_SIZE], temp[SUBFRAME_SIZE],

572 mem[SUBFRAME_SIZE];

573 float sum1 = 0.0, sum2 = 0.0, gamma, gain;

574 float tilt = pfc->tilt;

575 int i, n, best;

576

577 bandwidth_expansion(wcoef1, coeff, pfc->p1);

578 bandwidth_expansion(wcoef2, coeff, pfc->p2);

579

580 /* Tilt compensation filter, TIA/IS-127 5.9.1 */

581 for (i = 0; i < length - 1; i++)

582 sum2 += in[i] * in[i + 1];

583 if (sum2 < 0.0)

584 tilt = 0.0;

585

586 for (i = 0; i < length; i++) {

587 scratch[i] = in[i] - tilt * e->last;

588 e->last = in[i];

589 }

590

591 /* Short term residual filter, TIA/IS-127 5.9.2 */

592 residual_filter(&e->postfilter_residual[ACB_SIZE], scratch, wcoef1, e->postfilter_fir, length);

593

594 /* Long term postfilter */

595 best = idx;

596 for (i = FFMIN(MIN_DELAY, idx - 3); i <= FFMAX(MAX_DELAY, idx + 3); i++) {

597 for (n = ACB_SIZE, sum2 = 0; n < ACB_SIZE + length; n++)

598 sum2 += e->postfilter_residual[n] * e->postfilter_residual[n - i];

599 if (sum2 > sum1) {

600 sum1 = sum2;

601 best = i;

602 }

603 }

604

605 for (i = ACB_SIZE, sum1 = 0; i < ACB_SIZE + length; i++)

606 sum1 += e->postfilter_residual[i - best] * e->postfilter_residual[i - best];

607 for (i = ACB_SIZE, sum2 = 0; i < ACB_SIZE + length; i++)

608 sum2 += e->postfilter_residual[i] * e->postfilter_residual[i - best];

609

610 if (sum2 * sum1 == 0 || e->bitrate == RATE_QUANT) {

611 memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float));

612 } else {

613 gamma = sum2 / sum1;

614 if (gamma < 0.5)

615 memcpy(temp, e->postfilter_residual + ACB_SIZE, length * sizeof(float));

616 else {

617 gamma = FFMIN(gamma, 1.0);

618

619 for (i = 0; i < length; i++) {

620 temp[i] = e->postfilter_residual[ACB_SIZE + i] + gamma *

621 pfc->ltgain * e->postfilter_residual[ACB_SIZE + i - best];

622 }

623 }

624 }

625

626 memcpy(scratch, temp, length * sizeof(float));

627 memcpy(mem, e->postfilter_iir, FILTER_ORDER * sizeof(float));

628 synthesis_filter(scratch, wcoef2, mem, length, scratch);

629

630 /* Gain computation, TIA/IS-127 5.9.4-2 */

631 for (i = 0, sum1 = 0, sum2 = 0; i < length; i++) {

632 sum1 += in[i] * in[i];

633 sum2 += scratch[i] * scratch[i];

634 }

635 gain = sum2 ? sqrt(sum1 / sum2) : 1.0;

636

637 for (i = 0; i < length; i++)

638 temp[i] *= gain;

639

640 /* Short term postfilter */

641 synthesis_filter(temp, wcoef2, e->postfilter_iir, length, out);

642

643 memmove(e->postfilter_residual,

644 e->postfilter_residual + length, ACB_SIZE * sizeof(float));

645 }

646

647 static void frame_erasure(EVRCContext *e, float *samples)

648 {

649 float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES],

650 tmp[SUBFRAME_SIZE + 6], f;

651 int i, j;

652

653 for (i = 0; i < FILTER_ORDER; i++) {

654 if (e->bitrate != RATE_QUANT)

655 e->lspf[i] = e->prev_lspf[i] * 0.875 + 0.125 * (i + 1) * 0.048;

656 else

657 e->lspf[i] = e->prev_lspf[i];

658 }

659

660 if (e->prev_error_flag)

661 e->avg_acb_gain *= 0.75;

662 if (e->bitrate == RATE_FULL)

663 memcpy(e->pitch_back, e->pitch, ACB_SIZE * sizeof(float));

664 if (e->last_valid_bitrate == RATE_QUANT)

665 e->bitrate = RATE_QUANT;

666 else

667 e->bitrate = RATE_FULL;

668

669 if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) {

670 e->pitch_delay = e->prev_pitch_delay;

671 } else {

672 float sum = 0;

673

674 idelay[0] = idelay[1] = idelay[2] = MIN_DELAY;

675

676 for (i = 0; i < NB_SUBFRAMES; i++)

677 sum += evrc_energy_quant[e->prev_energy_gain][i];

678 sum /= (float) NB_SUBFRAMES;

679 sum = pow(10, sum);

680 for (i = 0; i < NB_SUBFRAMES; i++)

681 e->energy_vector[i] = sum;

682 }

683

684 if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15)

685 e->prev_pitch_delay = e->pitch_delay;

686

687 for (i = 0; i < NB_SUBFRAMES; i++) {

688 int subframe_size = subframe_sizes[i];

689 int pitch_lag;

690

691 interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i);

692

693 if (e->bitrate != RATE_QUANT) {

694 if (e->avg_acb_gain < 0.3) {

695 idelay[0] = estimation_delay[i];

696 idelay[1] = estimation_delay[i + 1];

697 idelay[2] = estimation_delay[i + 2];

698 } else {

699 interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i);

700 }

701 }

702

703 pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0);

704 decode_predictor_coeffs(ilspf, ilpc);

705

706 if (e->bitrate != RATE_QUANT) {

707 acb_excitation(e, e->pitch + ACB_SIZE,

708 e->avg_acb_gain, idelay, subframe_size);

709 for (j = 0; j < subframe_size; j++)

710 e->pitch[ACB_SIZE + j] *= e->fade_scale;

711 e->fade_scale = FFMAX(e->fade_scale - 0.05, 0.0);

712 } else {

713 for (j = 0; j < subframe_size; j++)

714 e->pitch[ACB_SIZE + j] = e->energy_vector[i];

715 }

716

717 memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));

718

719 if (e->bitrate != RATE_QUANT && e->avg_acb_gain < 0.4) {

720 f = 0.1 * e->avg_fcb_gain;

721 for (j = 0; j < subframe_size; j++)

722 e->pitch[ACB_SIZE + j] += f;

723 } else if (e->bitrate == RATE_QUANT) {

724 for (j = 0; j < subframe_size; j++)

725 e->pitch[ACB_SIZE + j] = e->energy_vector[i];

726 }

727

728 synthesis_filter(e->pitch + ACB_SIZE, ilpc,

729 e->synthesis, subframe_size, tmp);

730 postfilter(e, tmp, ilpc, samples, pitch_lag,

731 &postfilter_coeffs[e->bitrate], subframe_size);

732

733 samples += subframe_size;

734 }

735 }

736

737 static int evrc_decode_frame(AVCodecContext *avctx, void *data,

738 int *got_frame_ptr, AVPacket *avpkt)

739 {

740 const uint8_t *buf = avpkt->data;

741 AVFrame *frame = data;

742 EVRCContext *e = avctx->priv_data;

743 int buf_size = avpkt->size;

744 float ilspf[FILTER_ORDER], ilpc[FILTER_ORDER], idelay[NB_SUBFRAMES];

745 float *samples;

746 int i, j, ret, error_flag = 0;

747

748 frame->nb_samples = 160;

749 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

750 return ret;

751 samples = (float *)frame->data[0];

752

753 if ((e->bitrate = determine_bitrate(avctx, &buf_size, &buf)) == RATE_ERRS) {

754 warn_insufficient_frame_quality(avctx, "bitrate cannot be determined.");

755 goto erasure;

756 }

757 if (e->bitrate <= SILENCE || e->bitrate == RATE_QUARTER)

758 goto erasure;

759 if (e->bitrate == RATE_QUANT && e->last_valid_bitrate == RATE_FULL

760 && !e->prev_error_flag)

761 goto erasure;

762

763 init_get_bits(&e->gb, buf, 8 * buf_size);

764 memset(&e->frame, 0, sizeof(EVRCAFrame));

765

766 unpack_frame(e);

767

768 if (e->bitrate != RATE_QUANT) {

769 uint8_t *p = (uint8_t *) &e->frame;

770 for (i = 0; i < sizeof(EVRCAFrame); i++) {

771 if (p[i])

772 break;

773 }

774 if (i == sizeof(EVRCAFrame))

775 goto erasure;

776 } else if (e->frame.lsp[0] == 0xf &&

777 e->frame.lsp[1] == 0xf &&

778 e->frame.energy_gain == 0xff) {

779 goto erasure;

780 }

781

782 if (decode_lspf(e) < 0)

783 goto erasure;

784

785 if (e->bitrate == RATE_FULL || e->bitrate == RATE_HALF) {

786 /* Pitch delay parameter checking as per TIA/IS-127 5.1.5.1 */

787 if (e->frame.pitch_delay > MAX_DELAY - MIN_DELAY)

788 goto erasure;

789

790 e->pitch_delay = e->frame.pitch_delay + MIN_DELAY;

791

792 /* Delay diff parameter checking as per TIA/IS-127 5.1.5.2 */

793 if (e->frame.delay_diff) {

794 int p = e->pitch_delay - e->frame.delay_diff + 16;

795 if (p < MIN_DELAY || p > MAX_DELAY)

796 goto erasure;

797 }

798

799 /* Delay contour reconstruction as per TIA/IS-127 5.2.2.2 */

800 if (e->frame.delay_diff &&

801 e->bitrate == RATE_FULL && e->prev_error_flag) {

802 float delay;

803

804 memcpy(e->pitch, e->pitch_back, ACB_SIZE * sizeof(float));

805

806 delay = e->prev_pitch_delay;

807 e->prev_pitch_delay = delay - e->frame.delay_diff + 16.0;

808

809 if (fabs(e->pitch_delay - delay) > 15)

810 delay = e->pitch_delay;

811

812 for (i = 0; i < NB_SUBFRAMES; i++) {

813 int subframe_size = subframe_sizes[i];

814

815 interpolate_delay(idelay, delay, e->prev_pitch_delay, i);

816 acb_excitation(e, e->pitch + ACB_SIZE, e->avg_acb_gain, idelay, subframe_size);

817 memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));

818 }

819 }

820

821 /* Smoothing of the decoded delay as per TIA/IS-127 5.2.2.5 */

822 if (fabs(e->pitch_delay - e->prev_pitch_delay) > 15)

823 e->prev_pitch_delay = e->pitch_delay;

824

825 e->avg_acb_gain = e->avg_fcb_gain = 0.0;

826 } else {

827 idelay[0] = idelay[1] = idelay[2] = MIN_DELAY;

828

829 /* Decode frame energy vectors as per TIA/IS-127 5.7.2 */

830 for (i = 0; i < NB_SUBFRAMES; i++)

831 e->energy_vector[i] = pow(10, evrc_energy_quant[e->frame.energy_gain][i]);

832 e->prev_energy_gain = e->frame.energy_gain;

833 }

834

835 for (i = 0; i < NB_SUBFRAMES; i++) {

836 float tmp[SUBFRAME_SIZE + 6] = { 0 };

837 int subframe_size = subframe_sizes[i];

838 int pitch_lag;

839

840 interpolate_lsp(ilspf, e->lspf, e->prev_lspf, i);

841

842 if (e->bitrate != RATE_QUANT)

843 interpolate_delay(idelay, e->pitch_delay, e->prev_pitch_delay, i);

844

845 pitch_lag = lrintf((idelay[1] + idelay[0]) / 2.0);

846 decode_predictor_coeffs(ilspf, ilpc);

847

848 /* Bandwidth expansion as per TIA/IS-127 5.2.3.3 */

849 if (e->frame.lpc_flag && e->prev_error_flag)

850 bandwidth_expansion(ilpc, ilpc, 0.75);

851

852 if (e->bitrate != RATE_QUANT) {

853 float acb_sum, f;

854

855 f = exp((e->bitrate == RATE_HALF ? 0.5 : 0.25)

856 * (e->frame.fcb_gain[i] + 1));

857 acb_sum = pitch_gain_vq[e->frame.acb_gain[i]];

858 e->avg_acb_gain += acb_sum / NB_SUBFRAMES;

859 e->avg_fcb_gain += f / NB_SUBFRAMES;

860

861 acb_excitation(e, e->pitch + ACB_SIZE,

862 acb_sum, idelay, subframe_size);

863 fcb_excitation(e, e->frame.fcb_shape[i], tmp,

864 acb_sum, pitch_lag, subframe_size);

865

866 /* Total excitation generation as per TIA/IS-127 5.2.3.9 */

867 for (j = 0; j < subframe_size; j++)

868 e->pitch[ACB_SIZE + j] += f * tmp[j];

869 e->fade_scale = FFMIN(e->fade_scale + 0.2, 1.0);

870 } else {

871 for (j = 0; j < subframe_size; j++)

872 e->pitch[ACB_SIZE + j] = e->energy_vector[i];

873 }

874

875 memmove(e->pitch, e->pitch + subframe_size, ACB_SIZE * sizeof(float));

876

877 synthesis_filter(e->pitch + ACB_SIZE, ilpc,

878 e->synthesis, subframe_size, tmp);

879 postfilter(e, tmp, ilpc, samples, pitch_lag,

880 &postfilter_coeffs[e->bitrate], subframe_size);

881

882 samples += subframe_size;

883 }

884

885 if (error_flag) {

886 erasure:

887 error_flag = 1;

888 av_log(avctx, AV_LOG_WARNING, "frame erasure\n");

889 frame_erasure(e, samples);

890 }

891

892 memcpy(e->prev_lspf, e->lspf, sizeof(e->prev_lspf));

893 e->prev_error_flag = error_flag;

894 e->last_valid_bitrate = e->bitrate;

895

896 if (e->bitrate != RATE_QUANT)

897 e->prev_pitch_delay = e->pitch_delay;

898

899 samples = (float *)frame->data[0];

900 for (i = 0; i < 160; i++)

901 samples[i] /= 32768;

902

903 *got_frame_ptr = 1;

904

905 return avpkt->size;

906 }

907

908 AVCodec ff_evrc_decoder = {

909 .name = "evrc",

910 .type = AVMEDIA_TYPE_AUDIO,

911 .id = AV_CODEC_ID_EVRC,

912 .init = evrc_decode_init,

913 .decode = evrc_decode_frame,

914 .capabilities = CODEC_CAP_DR1,

915 .priv_data_size = sizeof(EVRCContext),

916 .long_name = NULL_IF_CONFIG_SMALL("EVRC (Enhanced Variable Rate Codec)"),

917 };

Generated on Wed Jul 10 2013 23:47:57 for FFmpeg by doxygen 1.8.2