FFmpeg: libavcodec/sipr.c Source File

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sipr.c

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1 /*

2 * SIPR / ACELP.NET decoder

3 *

6 *

7 * This file is part of FFmpeg.

8 *

9 * FFmpeg is free software; you can redistribute it and/or

10 * modify it under the terms of the GNU Lesser General Public

11 * License as published by the Free Software Foundation; either

12 * version 2.1 of the License, or (at your option) any later version.

13 *

14 * FFmpeg is distributed in the hope that it will be useful,

15 * but WITHOUT ANY WARRANTY; without even the implied warranty of

16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

17 * Lesser General Public License for more details.

18 *

19 * You should have received a copy of the GNU Lesser General Public

20 * License along with FFmpeg; if not, write to the Free Software

21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

22 */

24 #include <math.h>

25 #include <stdint.h>

26 #include <string.h>

28 #include "libavutil/channel_layout.h"

29 #include "libavutil/float_dsp.h"

30 #include "libavutil/mathematics.h"

31 #include "avcodec.h"

32 #define BITSTREAM_READER_LE

33 #include "get_bits.h"

34 #include "internal.h"

36 #include "lsp.h"

37 #include "acelp_vectors.h"

38 #include "acelp_pitch_delay.h"

39 #include "acelp_filters.h"

40 #include "celp_filters.h"

42 #define MAX_SUBFRAME_COUNT 5

44 #include "sipr.h"

45 #include "siprdata.h"

47 typedef struct {

48 const char *mode_name;

49 uint16_t bits_per_frame;

50 uint8_t subframe_count;

51 uint8_t frames_per_packet;

52 float pitch_sharp_factor;

54 /* bitstream parameters */

55 uint8_t number_of_fc_indexes;

56 uint8_t ma_predictor_bits; ///< size in bits of the switched MA predictor

58 /** size in bits of the i-th stage vector of quantizer */

59 uint8_t vq_indexes_bits[5];

61 /** size in bits of the adaptive-codebook index for every subframe */

62 uint8_t pitch_delay_bits[5];

64 uint8_t gp_index_bits;

65 uint8_t fc_index_bits[10]; ///< size in bits of the fixed codebook indexes

66 uint8_t gc_index_bits; ///< size in bits of the gain codebook indexes

67 } SiprModeParam;

69 static const SiprModeParam modes[MODE_COUNT] = {

70 [MODE_16k] = {

71 .mode_name = "16k",

72 .bits_per_frame = 160,

73 .subframe_count = SUBFRAME_COUNT_16k,

74 .frames_per_packet = 1,

75 .pitch_sharp_factor = 0.00,

77 .number_of_fc_indexes = 10,

78 .ma_predictor_bits = 1,

79 .vq_indexes_bits = {7, 8, 7, 7, 7},

80 .pitch_delay_bits = {9, 6},

81 .gp_index_bits = 4,

82 .fc_index_bits = {4, 5, 4, 5, 4, 5, 4, 5, 4, 5},

83 .gc_index_bits = 5

84 },

86 [MODE_8k5] = {

87 .mode_name = "8k5",

88 .bits_per_frame = 152,

89 .subframe_count = 3,

90 .frames_per_packet = 1,

91 .pitch_sharp_factor = 0.8,

93 .number_of_fc_indexes = 3,

94 .ma_predictor_bits = 0,

95 .vq_indexes_bits = {6, 7, 7, 7, 5},

96 .pitch_delay_bits = {8, 5, 5},

97 .gp_index_bits = 0,

98 .fc_index_bits = {9, 9, 9},

99 .gc_index_bits = 7

100 },

101

102 [MODE_6k5] = {

103 .mode_name = "6k5",

104 .bits_per_frame = 232,

105 .subframe_count = 3,

106 .frames_per_packet = 2,

107 .pitch_sharp_factor = 0.8,

108

109 .number_of_fc_indexes = 3,

110 .ma_predictor_bits = 0,

111 .vq_indexes_bits = {6, 7, 7, 7, 5},

112 .pitch_delay_bits = {8, 5, 5},

113 .gp_index_bits = 0,

114 .fc_index_bits = {5, 5, 5},

115 .gc_index_bits = 7

116 },

117

118 [MODE_5k0] = {

119 .mode_name = "5k0",

120 .bits_per_frame = 296,

121 .subframe_count = 5,

122 .frames_per_packet = 2,

123 .pitch_sharp_factor = 0.85,

124

125 .number_of_fc_indexes = 1,

126 .ma_predictor_bits = 0,

127 .vq_indexes_bits = {6, 7, 7, 7, 5},

128 .pitch_delay_bits = {8, 5, 8, 5, 5},

129 .gp_index_bits = 0,

130 .fc_index_bits = {10},

131 .gc_index_bits = 7

132 }

133 };

134

135 const float ff_pow_0_5[] = {

136 1.0/(1 << 1), 1.0/(1 << 2), 1.0/(1 << 3), 1.0/(1 << 4),

137 1.0/(1 << 5), 1.0/(1 << 6), 1.0/(1 << 7), 1.0/(1 << 8),

138 1.0/(1 << 9), 1.0/(1 << 10), 1.0/(1 << 11), 1.0/(1 << 12),

139 1.0/(1 << 13), 1.0/(1 << 14), 1.0/(1 << 15), 1.0/(1 << 16)

140 };

141

142 static void dequant(float *out, const int *idx, const float *cbs[])

143 {

144 int i;

145 int stride = 2;

146 int num_vec = 5;

147

148 for (i = 0; i < num_vec; i++)

149 memcpy(out + stride*i, cbs[i] + stride*idx[i], stride*sizeof(float));

150

151 }

152

153 static void lsf_decode_fp(float *lsfnew, float *lsf_history,

154 const SiprParameters *parm)

155 {

156 int i;

157 float lsf_tmp[LP_FILTER_ORDER];

158

159 dequant(lsf_tmp, parm->vq_indexes, lsf_codebooks);

160

161 for (i = 0; i < LP_FILTER_ORDER; i++)

162 lsfnew[i] = lsf_history[i] * 0.33 + lsf_tmp[i] + mean_lsf[i];

163

164 ff_sort_nearly_sorted_floats(lsfnew, LP_FILTER_ORDER - 1);

165

166 /* Note that a minimum distance is not enforced between the last value and

167 the previous one, contrary to what is done in ff_acelp_reorder_lsf() */

168 ff_set_min_dist_lsf(lsfnew, LSFQ_DIFF_MIN, LP_FILTER_ORDER - 1);

169 lsfnew[9] = FFMIN(lsfnew[LP_FILTER_ORDER - 1], 1.3 * M_PI);

170

171 memcpy(lsf_history, lsf_tmp, LP_FILTER_ORDER * sizeof(*lsf_history));

172

173 for (i = 0; i < LP_FILTER_ORDER - 1; i++)

174 lsfnew[i] = cos(lsfnew[i]);

175 lsfnew[LP_FILTER_ORDER - 1] *= 6.153848 / M_PI;

176 }

177

178 /** Apply pitch lag to the fixed vector (AMR section 6.1.2). */

179 static void pitch_sharpening(int pitch_lag_int, float beta,

180 float *fixed_vector)

181 {

182 int i;

183

184 for (i = pitch_lag_int; i < SUBFR_SIZE; i++)

185 fixed_vector[i] += beta * fixed_vector[i - pitch_lag_int];

186 }

187

188 /**

189 * Extract decoding parameters from the input bitstream.

190 * @param parms parameters structure

191 * @param pgb pointer to initialized GetBitContext structure

192 */

193 static void decode_parameters(SiprParameters* parms, GetBitContext *pgb,

194 const SiprModeParam *p)

195 {

196 int i, j;

197

198 if (p->ma_predictor_bits)

199 parms->ma_pred_switch = get_bits(pgb, p->ma_predictor_bits);

200

201 for (i = 0; i < 5; i++)

202 parms->vq_indexes[i] = get_bits(pgb, p->vq_indexes_bits[i]);

203

204 for (i = 0; i < p->subframe_count; i++) {

205 parms->pitch_delay[i] = get_bits(pgb, p->pitch_delay_bits[i]);

206 if (p->gp_index_bits)

207 parms->gp_index[i] = get_bits(pgb, p->gp_index_bits);

208

209 for (j = 0; j < p->number_of_fc_indexes; j++)

210 parms->fc_indexes[i][j] = get_bits(pgb, p->fc_index_bits[j]);

211

212 parms->gc_index[i] = get_bits(pgb, p->gc_index_bits);

213 }

214 }

215

216 static void sipr_decode_lp(float *lsfnew, const float *lsfold, float *Az,

217 int num_subfr)

218 {

219 double lsfint[LP_FILTER_ORDER];

220 int i,j;

221 float t, t0 = 1.0 / num_subfr;

222

223 t = t0 * 0.5;

224 for (i = 0; i < num_subfr; i++) {

225 for (j = 0; j < LP_FILTER_ORDER; j++)

226 lsfint[j] = lsfold[j] * (1 - t) + t * lsfnew[j];

227

228 ff_amrwb_lsp2lpc(lsfint, Az, LP_FILTER_ORDER);

229 Az += LP_FILTER_ORDER;

230 t += t0;

231 }

232 }

233

234 /**

235 * Evaluate the adaptive impulse response.

236 */

237 static void eval_ir(const float *Az, int pitch_lag, float *freq,

238 float pitch_sharp_factor)

239 {

240 float tmp1[SUBFR_SIZE+1], tmp2[LP_FILTER_ORDER+1];

241 int i;

242

243 tmp1[0] = 1.0;

244 for (i = 0; i < LP_FILTER_ORDER; i++) {

245 tmp1[i+1] = Az[i] * ff_pow_0_55[i];

246 tmp2[i ] = Az[i] * ff_pow_0_7 [i];

247 }

248 memset(tmp1 + 11, 0, 37 * sizeof(float));

249

250 ff_celp_lp_synthesis_filterf(freq, tmp2, tmp1, SUBFR_SIZE,

251 LP_FILTER_ORDER);

252

253 pitch_sharpening(pitch_lag, pitch_sharp_factor, freq);

254 }

255

256 /**

257 * Evaluate the convolution of a vector with a sparse vector.

258 */

259 static void convolute_with_sparse(float *out, const AMRFixed *pulses,

260 const float *shape, int length)

261 {

262 int i, j;

263

264 memset(out, 0, length*sizeof(float));

265 for (i = 0; i < pulses->n; i++)

266 for (j = pulses->x[i]; j < length; j++)

267 out[j] += pulses->y[i] * shape[j - pulses->x[i]];

268 }

269

270 /**

271 * Apply postfilter, very similar to AMR one.

272 */

273 static void postfilter_5k0(SiprContext *ctx, const float *lpc, float *samples)

274 {

275 float buf[SUBFR_SIZE + LP_FILTER_ORDER];

276 float *pole_out = buf + LP_FILTER_ORDER;

277 float lpc_n[LP_FILTER_ORDER];

278 float lpc_d[LP_FILTER_ORDER];

279 int i;

280

281 for (i = 0; i < LP_FILTER_ORDER; i++) {

282 lpc_d[i] = lpc[i] * ff_pow_0_75[i];

283 lpc_n[i] = lpc[i] * ff_pow_0_5 [i];

284 };

285

286 memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem,

287 LP_FILTER_ORDER*sizeof(float));

288

289 ff_celp_lp_synthesis_filterf(pole_out, lpc_d, samples, SUBFR_SIZE,

290 LP_FILTER_ORDER);

291

292 memcpy(ctx->postfilter_mem, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,

293 LP_FILTER_ORDER*sizeof(float));

294

295 ff_tilt_compensation(&ctx->tilt_mem, 0.4, pole_out, SUBFR_SIZE);

296

297 memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem5k0,

298 LP_FILTER_ORDER*sizeof(*pole_out));

299

300 memcpy(ctx->postfilter_mem5k0, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,

301 LP_FILTER_ORDER*sizeof(*pole_out));

302

303 ff_celp_lp_zero_synthesis_filterf(samples, lpc_n, pole_out, SUBFR_SIZE,

304 LP_FILTER_ORDER);

305

306 }

307

308 static void decode_fixed_sparse(AMRFixed *fixed_sparse, const int16_t *pulses,

309 SiprMode mode, int low_gain)

310 {

311 int i;

312

313 switch (mode) {

314 case MODE_6k5:

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

316 fixed_sparse->x[i] = 3 * (pulses[i] & 0xf) + i;

317 fixed_sparse->y[i] = pulses[i] & 0x10 ? -1 : 1;

318 }

319 fixed_sparse->n = 3;

320 break;

321 case MODE_8k5:

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

323 fixed_sparse->x[2*i ] = 3 * ((pulses[i] >> 4) & 0xf) + i;

324 fixed_sparse->x[2*i + 1] = 3 * ( pulses[i] & 0xf) + i;

325

326 fixed_sparse->y[2*i ] = (pulses[i] & 0x100) ? -1.0: 1.0;

327

328 fixed_sparse->y[2*i + 1] =

329 (fixed_sparse->x[2*i + 1] < fixed_sparse->x[2*i]) ?

330 -fixed_sparse->y[2*i ] : fixed_sparse->y[2*i];

331 }

332

333 fixed_sparse->n = 6;

334 break;

335 case MODE_5k0:

336 default:

337 if (low_gain) {

338 int offset = (pulses[0] & 0x200) ? 2 : 0;

339 int val = pulses[0];

340

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

342 int index = (val & 0x7) * 6 + 4 - i*2;

343

344 fixed_sparse->y[i] = (offset + index) & 0x3 ? -1 : 1;

345 fixed_sparse->x[i] = index;

346

347 val >>= 3;

348 }

349 fixed_sparse->n = 3;

350 } else {

351 int pulse_subset = (pulses[0] >> 8) & 1;

352

353 fixed_sparse->x[0] = ((pulses[0] >> 4) & 15) * 3 + pulse_subset;

354 fixed_sparse->x[1] = ( pulses[0] & 15) * 3 + pulse_subset + 1;

355

356 fixed_sparse->y[0] = pulses[0] & 0x200 ? -1 : 1;

357 fixed_sparse->y[1] = -fixed_sparse->y[0];

358 fixed_sparse->n = 2;

359 }

360 break;

361 }

362 }

363

364 static void decode_frame(SiprContext *ctx, SiprParameters *params,

365 float *out_data)

366 {

367 int i, j;

368 int subframe_count = modes[ctx->mode].subframe_count;

369 int frame_size = subframe_count * SUBFR_SIZE;

370 float Az[LP_FILTER_ORDER * MAX_SUBFRAME_COUNT];

371 float *excitation;

372 float ir_buf[SUBFR_SIZE + LP_FILTER_ORDER];

373 float lsf_new[LP_FILTER_ORDER];

374 float *impulse_response = ir_buf + LP_FILTER_ORDER;

375 float *synth = ctx->synth_buf + 16; // 16 instead of LP_FILTER_ORDER for

376 // memory alignment

377 int t0_first = 0;

378 AMRFixed fixed_cb;

379

380 memset(ir_buf, 0, LP_FILTER_ORDER * sizeof(float));

381 lsf_decode_fp(lsf_new, ctx->lsf_history, params);

382

383 sipr_decode_lp(lsf_new, ctx->lsp_history, Az, subframe_count);

384

385 memcpy(ctx->lsp_history, lsf_new, LP_FILTER_ORDER * sizeof(float));

386

387 excitation = ctx->excitation + PITCH_DELAY_MAX + L_INTERPOL;

388

389 for (i = 0; i < subframe_count; i++) {

390 float *pAz = Az + i*LP_FILTER_ORDER;

391 float fixed_vector[SUBFR_SIZE];

392 int T0,T0_frac;

393 float pitch_gain, gain_code, avg_energy;

394

395 ff_decode_pitch_lag(&T0, &T0_frac, params->pitch_delay[i], t0_first, i,

396 ctx->mode == MODE_5k0, 6);

397

398 if (i == 0 || (i == 2 && ctx->mode == MODE_5k0))

399 t0_first = T0;

400

401 ff_acelp_interpolatef(excitation, excitation - T0 + (T0_frac <= 0),

402 ff_b60_sinc, 6,

403 2 * ((2 + T0_frac)%3 + 1), LP_FILTER_ORDER,

404 SUBFR_SIZE);

405

406 decode_fixed_sparse(&fixed_cb, params->fc_indexes[i], ctx->mode,

407 ctx->past_pitch_gain < 0.8);

408

409 eval_ir(pAz, T0, impulse_response, modes[ctx->mode].pitch_sharp_factor);

410

411 convolute_with_sparse(fixed_vector, &fixed_cb, impulse_response,

412 SUBFR_SIZE);

413

414 avg_energy = (0.01 + avpriv_scalarproduct_float_c(fixed_vector,

415 fixed_vector,

416 SUBFR_SIZE)) /

417 SUBFR_SIZE;

418

419 ctx->past_pitch_gain = pitch_gain = gain_cb[params->gc_index[i]][0];

420

421 gain_code = ff_amr_set_fixed_gain(gain_cb[params->gc_index[i]][1],

422 avg_energy, ctx->energy_history,

423 34 - 15.0/(0.05*M_LN10/M_LN2),

424 pred);

425

426 ff_weighted_vector_sumf(excitation, excitation, fixed_vector,

427 pitch_gain, gain_code, SUBFR_SIZE);

428

429 pitch_gain *= 0.5 * pitch_gain;

430 pitch_gain = FFMIN(pitch_gain, 0.4);

431

432 ctx->gain_mem = 0.7 * ctx->gain_mem + 0.3 * pitch_gain;

433 ctx->gain_mem = FFMIN(ctx->gain_mem, pitch_gain);

434 gain_code *= ctx->gain_mem;

435

436 for (j = 0; j < SUBFR_SIZE; j++)

437 fixed_vector[j] = excitation[j] - gain_code * fixed_vector[j];

438

439 if (ctx->mode == MODE_5k0) {

440 postfilter_5k0(ctx, pAz, fixed_vector);

441

442 ff_celp_lp_synthesis_filterf(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i*SUBFR_SIZE,

443 pAz, excitation, SUBFR_SIZE,

444 LP_FILTER_ORDER);

445 }

446

447 ff_celp_lp_synthesis_filterf(synth + i*SUBFR_SIZE, pAz, fixed_vector,

448 SUBFR_SIZE, LP_FILTER_ORDER);

449

450 excitation += SUBFR_SIZE;

451 }

452

453 memcpy(synth - LP_FILTER_ORDER, synth + frame_size - LP_FILTER_ORDER,

454 LP_FILTER_ORDER * sizeof(float));

455

456 if (ctx->mode == MODE_5k0) {

457 for (i = 0; i < subframe_count; i++) {

458 float energy = avpriv_scalarproduct_float_c(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,

459 ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,

460 SUBFR_SIZE);

461 ff_adaptive_gain_control(&synth[i * SUBFR_SIZE],

462 &synth[i * SUBFR_SIZE], energy,

463 SUBFR_SIZE, 0.9, &ctx->postfilter_agc);

464 }

465

466 memcpy(ctx->postfilter_syn5k0, ctx->postfilter_syn5k0 + frame_size,

467 LP_FILTER_ORDER*sizeof(float));

468 }

469 memmove(ctx->excitation, excitation - PITCH_DELAY_MAX - L_INTERPOL,

470 (PITCH_DELAY_MAX + L_INTERPOL) * sizeof(float));

471

472 ff_acelp_apply_order_2_transfer_function(out_data, synth,

473 (const float[2]) {-1.99997 , 1.000000000},

474 (const float[2]) {-1.93307352, 0.935891986},

475 0.939805806,

476 ctx->highpass_filt_mem,

477 frame_size);

478 }

479

480 static av_cold int sipr_decoder_init(AVCodecContext * avctx)

481 {

482 SiprContext *ctx = avctx->priv_data;

483 int i;

484

485 switch (avctx->block_align) {

486 case 20: ctx->mode = MODE_16k; break;

487 case 19: ctx->mode = MODE_8k5; break;

488 case 29: ctx->mode = MODE_6k5; break;

489 case 37: ctx->mode = MODE_5k0; break;

490 default:

491 if (avctx->bit_rate > 12200) ctx->mode = MODE_16k;

492 else if (avctx->bit_rate > 7500 ) ctx->mode = MODE_8k5;

493 else if (avctx->bit_rate > 5750 ) ctx->mode = MODE_6k5;

494 else ctx->mode = MODE_5k0;

495 av_log(avctx, AV_LOG_WARNING,

496 "Invalid block_align: %d. Mode %s guessed based on bitrate: %d\n",

497 avctx->block_align, modes[ctx->mode].mode_name, avctx->bit_rate);

498 }

499

500 av_log(avctx, AV_LOG_DEBUG, "Mode: %s\n", modes[ctx->mode].mode_name);

501

502 if (ctx->mode == MODE_16k) {

503 ff_sipr_init_16k(ctx);

504 ctx->decode_frame = ff_sipr_decode_frame_16k;

505 } else {

506 ctx->decode_frame = decode_frame;

507 }

508

509 for (i = 0; i < LP_FILTER_ORDER; i++)

510 ctx->lsp_history[i] = cos((i+1) * M_PI / (LP_FILTER_ORDER + 1));

511

512 for (i = 0; i < 4; i++)

513 ctx->energy_history[i] = -14;

514

515 avctx->channels = 1;

516 avctx->channel_layout = AV_CH_LAYOUT_MONO;

517 avctx->sample_fmt = AV_SAMPLE_FMT_FLT;

518

519 return 0;

520 }

521

522 static int sipr_decode_frame(AVCodecContext *avctx, void *data,

523 int *got_frame_ptr, AVPacket *avpkt)

524 {

525 SiprContext *ctx = avctx->priv_data;

526 AVFrame *frame = data;

527 const uint8_t *buf=avpkt->data;

528 SiprParameters parm;

529 const SiprModeParam *mode_par = &modes[ctx->mode];

530 GetBitContext gb;

531 float *samples;

532 int subframe_size = ctx->mode == MODE_16k ? L_SUBFR_16k : SUBFR_SIZE;

533 int i, ret;

534

535 ctx->avctx = avctx;

536 if (avpkt->size < (mode_par->bits_per_frame >> 3)) {

537 av_log(avctx, AV_LOG_ERROR,

538 "Error processing packet: packet size (%d) too small\n",

539 avpkt->size);

540 return -1;

541 }

542

543 /* get output buffer */

544 frame->nb_samples = mode_par->frames_per_packet * subframe_size *

545 mode_par->subframe_count;

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

547 return ret;

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

549

550 init_get_bits(&gb, buf, mode_par->bits_per_frame);

551

552 for (i = 0; i < mode_par->frames_per_packet; i++) {

553 decode_parameters(&parm, &gb, mode_par);

554

555 ctx->decode_frame(ctx, &parm, samples);

556

557 samples += subframe_size * mode_par->subframe_count;

558 }

559

560 *got_frame_ptr = 1;

561

562 return mode_par->bits_per_frame >> 3;

563 }

564

565 AVCodec ff_sipr_decoder = {

566 .name = "sipr",

567 .long_name = NULL_IF_CONFIG_SMALL("RealAudio SIPR / ACELP.NET"),

568 .type = AVMEDIA_TYPE_AUDIO,

569 .id = AV_CODEC_ID_SIPR,

570 .priv_data_size = sizeof(SiprContext),

571 .init = sipr_decoder_init,

572 .decode = sipr_decode_frame,

573 .capabilities = CODEC_CAP_DR1,

574 };

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