FFmpeg: libavcodec/twinvq.c Source File

FFmpeg

[フレーム]

libavcodec

twinvq.c

Go to the documentation of this file.

1 /*

2 * TwinVQ 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 #include <math.h>

23 #include <stdint.h>

25 #include "libavutil/channel_layout.h"

26 #include "libavutil/float_dsp.h"

27 #include "avcodec.h"

28 #include "fft.h"

29 #include "internal.h"

30 #include "lsp.h"

31 #include "sinewin.h"

32 #include "twinvq.h"

34 /**

35 * Evaluate a single LPC amplitude spectrum envelope coefficient from the line

36 * spectrum pairs.

37 *

38 * @param lsp a vector of the cosine of the LSP values

39 * @param cos_val cos(PI*i/N) where i is the index of the LPC amplitude

40 * @param order the order of the LSP (and the size of the *lsp buffer). Must

41 * be a multiple of four.

42 * @return the LPC value

43 *

44 * @todo reuse code from Vorbis decoder: vorbis_floor0_decode

45 */

46 static float eval_lpc_spectrum(const float *lsp, float cos_val, int order)

47 {

48 int j;

49 float p = 0.5f;

50 float q = 0.5f;

51 float two_cos_w = 2.0f * cos_val;

53 for (j = 0; j + 1 < order; j += 2 * 2) {

54 // Unroll the loop once since order is a multiple of four

55 q *= lsp[j] - two_cos_w;

56 p *= lsp[j + 1] - two_cos_w;

58 q *= lsp[j + 2] - two_cos_w;

59 p *= lsp[j + 3] - two_cos_w;

60 }

62 p *= p * (2.0f - two_cos_w);

63 q *= q * (2.0f + two_cos_w);

65 return 0.5 / (p + q);

66 }

68 /**

69 * Evaluate the LPC amplitude spectrum envelope from the line spectrum pairs.

70 */

71 static void eval_lpcenv(TwinVQContext *tctx, const float *cos_vals, float *lpc)

72 {

73 int i;

74 const TwinVQModeTab *mtab = tctx->mtab;

75 int size_s = mtab->size / mtab->fmode[TWINVQ_FT_SHORT].sub;

77 for (i = 0; i < size_s / 2; i++) {

78 float cos_i = tctx->cos_tabs[0][i];

79 lpc[i] = eval_lpc_spectrum(cos_vals, cos_i, mtab->n_lsp);

80 lpc[size_s - i - 1] = eval_lpc_spectrum(cos_vals, -cos_i, mtab->n_lsp);

81 }

82 }

84 static void interpolate(float *out, float v1, float v2, int size)

85 {

86 int i;

87 float step = (v1 - v2) / (size + 1);

89 for (i = 0; i < size; i++) {

90 v2 += step;

91 out[i] = v2;

92 }

93 }

95 static inline float get_cos(int idx, int part, const float *cos_tab, int size)

96 {

97 return part ? -cos_tab[size - idx - 1]

98 : cos_tab[idx];

99 }

100

101 /**

102 * Evaluate the LPC amplitude spectrum envelope from the line spectrum pairs.

103 * Probably for speed reasons, the coefficients are evaluated as

104 * siiiibiiiisiiiibiiiisiiiibiiiisiiiibiiiis ...

105 * where s is an evaluated value, i is a value interpolated from the others

106 * and b might be either calculated or interpolated, depending on an

107 * unexplained condition.

108 *

109 * @param step the size of a block "siiiibiiii"

110 * @param in the cosine of the LSP data

111 * @param part is 0 for 0...PI (positive cosine values) and 1 for PI...2PI

112 * (negative cosine values)

113 * @param size the size of the whole output

114 */

115 static inline void eval_lpcenv_or_interp(TwinVQContext *tctx,

116 enum TwinVQFrameType ftype,

117 float *out, const float *in,

118 int size, int step, int part)

119 {

120 int i;

121 const TwinVQModeTab *mtab = tctx->mtab;

122 const float *cos_tab = tctx->cos_tabs[ftype];

123

124 // Fill the 's'

125 for (i = 0; i < size; i += step)

126 out[i] =

127 eval_lpc_spectrum(in,

128 get_cos(i, part, cos_tab, size),

129 mtab->n_lsp);

130

131 // Fill the 'iiiibiiii'

132 for (i = step; i <= size - 2 * step; i += step) {

133 if (out[i + step] + out[i - step] > 1.95 * out[i] ||

134 out[i + step] >= out[i - step]) {

135 interpolate(out + i - step + 1, out[i], out[i - step], step - 1);

136 } else {

137 out[i - step / 2] =

138 eval_lpc_spectrum(in,

139 get_cos(i - step / 2, part, cos_tab, size),

140 mtab->n_lsp);

141 interpolate(out + i - step + 1, out[i - step / 2],

142 out[i - step], step / 2 - 1);

143 interpolate(out + i - step / 2 + 1, out[i],

144 out[i - step / 2], step / 2 - 1);

145 }

146 }

147

148 interpolate(out + size - 2 * step + 1, out[size - step],

149 out[size - 2 * step], step - 1);

150 }

151

152 static void eval_lpcenv_2parts(TwinVQContext *tctx, enum TwinVQFrameType ftype,

153 const float *buf, float *lpc,

154 int size, int step)

155 {

156 eval_lpcenv_or_interp(tctx, ftype, lpc, buf, size / 2, step, 0);

157 eval_lpcenv_or_interp(tctx, ftype, lpc + size / 2, buf, size / 2,

158 2 * step, 1);

159

160 interpolate(lpc + size / 2 - step + 1, lpc[size / 2],

161 lpc[size / 2 - step], step);

162

163 twinvq_memset_float(lpc + size - 2 * step + 1, lpc[size - 2 * step],

164 2 * step - 1);

165 }

166

167 /**

168 * Inverse quantization. Read CB coefficients for cb1 and cb2 from the

169 * bitstream, sum the corresponding vectors and write the result to *out

170 * after permutation.

171 */

172 static void dequant(TwinVQContext *tctx, const uint8_t *cb_bits, float *out,

173 enum TwinVQFrameType ftype,

174 const int16_t *cb0, const int16_t *cb1, int cb_len)

175 {

176 int pos = 0;

177 int i, j;

178

179 for (i = 0; i < tctx->n_div[ftype]; i++) {

180 int tmp0, tmp1;

181 int sign0 = 1;

182 int sign1 = 1;

183 const int16_t *tab0, *tab1;

184 int length = tctx->length[ftype][i >= tctx->length_change[ftype]];

185 int bitstream_second_part = (i >= tctx->bits_main_spec_change[ftype]);

186

187 int bits = tctx->bits_main_spec[0][ftype][bitstream_second_part];

188 tmp0 = *cb_bits++;

189 if (bits == 7) {

190 if (tmp0 & 0x40)

191 sign0 = -1;

192 tmp0 &= 0x3F;

193 }

194

195 bits = tctx->bits_main_spec[1][ftype][bitstream_second_part];

196 tmp1 = *cb_bits++;

197 if (bits == 7) {

198 if (tmp1 & 0x40)

199 sign1 = -1;

200 tmp1 &= 0x3F;

201 }

202

203 tab0 = cb0 + tmp0 * cb_len;

204 tab1 = cb1 + tmp1 * cb_len;

205

206 for (j = 0; j < length; j++)

207 out[tctx->permut[ftype][pos + j]] = sign0 * tab0[j] +

208 sign1 * tab1[j];

209

210 pos += length;

211 }

212 }

213

214 static void dec_gain(TwinVQContext *tctx,

215 enum TwinVQFrameType ftype, float *out)

216 {

217 const TwinVQModeTab *mtab = tctx->mtab;

218 const TwinVQFrameData *bits = &tctx->bits;

219 int i, j;

220 int sub = mtab->fmode[ftype].sub;

221 float step = TWINVQ_AMP_MAX / ((1 << TWINVQ_GAIN_BITS) - 1);

222 float sub_step = TWINVQ_SUB_AMP_MAX / ((1 << TWINVQ_SUB_GAIN_BITS) - 1);

223

224 if (ftype == TWINVQ_FT_LONG) {

225 for (i = 0; i < tctx->avctx->channels; i++)

226 out[i] = (1.0 / (1 << 13)) *

227 twinvq_mulawinv(step * 0.5 + step * bits->gain_bits[i],

228 TWINVQ_AMP_MAX, TWINVQ_MULAW_MU);

229 } else {

230 for (i = 0; i < tctx->avctx->channels; i++) {

231 float val = (1.0 / (1 << 23)) *

232 twinvq_mulawinv(step * 0.5 + step * bits->gain_bits[i],

233 TWINVQ_AMP_MAX, TWINVQ_MULAW_MU);

234

235 for (j = 0; j < sub; j++)

236 out[i * sub + j] =

237 val * twinvq_mulawinv(sub_step * 0.5 +

238 sub_step * bits->sub_gain_bits[i * sub + j],

239 TWINVQ_SUB_AMP_MAX, TWINVQ_MULAW_MU);

240 }

241 }

242 }

243

244 /**

245 * Rearrange the LSP coefficients so that they have a minimum distance of

246 * min_dist. This function does it exactly as described in section of 3.2.4

247 * of the G.729 specification (but interestingly is different from what the

248 * reference decoder actually does).

249 */

250 static void rearrange_lsp(int order, float *lsp, float min_dist)

251 {

252 int i;

253 float min_dist2 = min_dist * 0.5;

254 for (i = 1; i < order; i++)

255 if (lsp[i] - lsp[i - 1] < min_dist) {

256 float avg = (lsp[i] + lsp[i - 1]) * 0.5;

257

258 lsp[i - 1] = avg - min_dist2;

259 lsp[i] = avg + min_dist2;

260 }

261 }

262

263 static void decode_lsp(TwinVQContext *tctx, int lpc_idx1, uint8_t *lpc_idx2,

264 int lpc_hist_idx, float *lsp, float *hist)

265 {

266 const TwinVQModeTab *mtab = tctx->mtab;

267 int i, j;

268

269 const float *cb = mtab->lspcodebook;

270 const float *cb2 = cb + (1 << mtab->lsp_bit1) * mtab->n_lsp;

271 const float *cb3 = cb2 + (1 << mtab->lsp_bit2) * mtab->n_lsp;

272

273 const int8_t funny_rounding[4] = {

274 -2,

275 mtab->lsp_split == 4 ? -2 : 1,

276 mtab->lsp_split == 4 ? -2 : 1,

277 0

278 };

279

280 j = 0;

281 for (i = 0; i < mtab->lsp_split; i++) {

282 int chunk_end = ((i + 1) * mtab->n_lsp + funny_rounding[i]) /

283 mtab->lsp_split;

284 for (; j < chunk_end; j++)

285 lsp[j] = cb[lpc_idx1 * mtab->n_lsp + j] +

286 cb2[lpc_idx2[i] * mtab->n_lsp + j];

287 }

288

289 rearrange_lsp(mtab->n_lsp, lsp, 0.0001);

290

291 for (i = 0; i < mtab->n_lsp; i++) {

292 float tmp1 = 1.0 - cb3[lpc_hist_idx * mtab->n_lsp + i];

293 float tmp2 = hist[i] * cb3[lpc_hist_idx * mtab->n_lsp + i];

294 hist[i] = lsp[i];

295 lsp[i] = lsp[i] * tmp1 + tmp2;

296 }

297

298 rearrange_lsp(mtab->n_lsp, lsp, 0.0001);

299 rearrange_lsp(mtab->n_lsp, lsp, 0.000095);

300 ff_sort_nearly_sorted_floats(lsp, mtab->n_lsp);

301 }

302

303 static void dec_lpc_spectrum_inv(TwinVQContext *tctx, float *lsp,

304 enum TwinVQFrameType ftype, float *lpc)

305 {

306 int i;

307 int size = tctx->mtab->size / tctx->mtab->fmode[ftype].sub;

308

309 for (i = 0; i < tctx->mtab->n_lsp; i++)

310 lsp[i] = 2 * cos(lsp[i]);

311

312 switch (ftype) {

313 case TWINVQ_FT_LONG:

314 eval_lpcenv_2parts(tctx, ftype, lsp, lpc, size, 8);

315 break;

316 case TWINVQ_FT_MEDIUM:

317 eval_lpcenv_2parts(tctx, ftype, lsp, lpc, size, 2);

318 break;

319 case TWINVQ_FT_SHORT:

320 eval_lpcenv(tctx, lsp, lpc);

321 break;

322 }

323 }

324

325 static const uint8_t wtype_to_wsize[] = { 0, 0, 2, 2, 2, 1, 0, 1, 1 };

326

327 static void imdct_and_window(TwinVQContext *tctx, enum TwinVQFrameType ftype,

328 int wtype, float *in, float *prev, int ch)

329 {

330 FFTContext *mdct = &tctx->mdct_ctx[ftype];

331 const TwinVQModeTab *mtab = tctx->mtab;

332 int bsize = mtab->size / mtab->fmode[ftype].sub;

333 int size = mtab->size;

334 float *buf1 = tctx->tmp_buf;

335 int j, first_wsize, wsize; // Window size

336 float *out = tctx->curr_frame + 2 * ch * mtab->size;

337 float *out2 = out;

338 float *prev_buf;

339 int types_sizes[] = {

340 mtab->size / mtab->fmode[TWINVQ_FT_LONG].sub,

341 mtab->size / mtab->fmode[TWINVQ_FT_MEDIUM].sub,

342 mtab->size / (mtab->fmode[TWINVQ_FT_SHORT].sub * 2),

343 };

344

345 wsize = types_sizes[wtype_to_wsize[wtype]];

346 first_wsize = wsize;

347 prev_buf = prev + (size - bsize) / 2;

348

349 for (j = 0; j < mtab->fmode[ftype].sub; j++) {

350 int sub_wtype = ftype == TWINVQ_FT_MEDIUM ? 8 : wtype;

351

352 if (!j && wtype == 4)

353 sub_wtype = 4;

354 else if (j == mtab->fmode[ftype].sub - 1 && wtype == 7)

355 sub_wtype = 7;

356

357 wsize = types_sizes[wtype_to_wsize[sub_wtype]];

358

359 mdct->imdct_half(mdct, buf1 + bsize * j, in + bsize * j);

360

361 tctx->fdsp.vector_fmul_window(out2, prev_buf + (bsize - wsize) / 2,

362 buf1 + bsize * j,

363 ff_sine_windows[av_log2(wsize)],

364 wsize / 2);

365 out2 += wsize;

366

367 memcpy(out2, buf1 + bsize * j + wsize / 2,

368 (bsize - wsize / 2) * sizeof(float));

369

370 out2 += ftype == TWINVQ_FT_MEDIUM ? (bsize - wsize) / 2 : bsize - wsize;

371

372 prev_buf = buf1 + bsize * j + bsize / 2;

373 }

374

375 tctx->last_block_pos[ch] = (size + first_wsize) / 2;

376 }

377

378 static void imdct_output(TwinVQContext *tctx, enum TwinVQFrameType ftype,

379 int wtype, float **out)

380 {

381 const TwinVQModeTab *mtab = tctx->mtab;

382 float *prev_buf = tctx->prev_frame + tctx->last_block_pos[0];

383 int size1, size2, i;

384

385 for (i = 0; i < tctx->avctx->channels; i++)

386 imdct_and_window(tctx, ftype, wtype,

387 tctx->spectrum + i * mtab->size,

388 prev_buf + 2 * i * mtab->size,

389 i);

390

391 if (!out)

392 return;

393

394 size2 = tctx->last_block_pos[0];

395 size1 = mtab->size - size2;

396

397 memcpy(&out[0][0], prev_buf, size1 * sizeof(out[0][0]));

398 memcpy(&out[0][size1], tctx->curr_frame, size2 * sizeof(out[0][0]));

399

400 if (tctx->avctx->channels == 2) {

401 memcpy(&out[1][0], &prev_buf[2 * mtab->size],

402 size1 * sizeof(out[1][0]));

403 memcpy(&out[1][size1], &tctx->curr_frame[2 * mtab->size],

404 size2 * sizeof(out[1][0]));

405 tctx->fdsp.butterflies_float(out[0], out[1], mtab->size);

406 }

407 }

408

409 static void read_and_decode_spectrum(TwinVQContext *tctx, float *out,

410 enum TwinVQFrameType ftype)

411 {

412 const TwinVQModeTab *mtab = tctx->mtab;

413 TwinVQFrameData *bits = &tctx->bits;

414 int channels = tctx->avctx->channels;

415 int sub = mtab->fmode[ftype].sub;

416 int block_size = mtab->size / sub;

417 float gain[TWINVQ_CHANNELS_MAX * TWINVQ_SUBBLOCKS_MAX];

418 float ppc_shape[TWINVQ_PPC_SHAPE_LEN_MAX * TWINVQ_CHANNELS_MAX * 4];

419

420 int i, j;

421

422 dequant(tctx, bits->main_coeffs, out, ftype,

423 mtab->fmode[ftype].cb0, mtab->fmode[ftype].cb1,

424 mtab->fmode[ftype].cb_len_read);

425

426 dec_gain(tctx, ftype, gain);

427

428 if (ftype == TWINVQ_FT_LONG) {

429 int cb_len_p = (tctx->n_div[3] + mtab->ppc_shape_len * channels - 1) /

430 tctx->n_div[3];

431 dequant(tctx, bits->ppc_coeffs, ppc_shape,

432 TWINVQ_FT_PPC, mtab->ppc_shape_cb,

433 mtab->ppc_shape_cb + cb_len_p * TWINVQ_PPC_SHAPE_CB_SIZE,

434 cb_len_p);

435 }

436

437 for (i = 0; i < channels; i++) {

438 float *chunk = out + mtab->size * i;

439 float lsp[TWINVQ_LSP_COEFS_MAX];

440

441 for (j = 0; j < sub; j++) {

442 tctx->dec_bark_env(tctx, bits->bark1[i][j],

443 bits->bark_use_hist[i][j], i,

444 tctx->tmp_buf, gain[sub * i + j], ftype);

445

446 tctx->fdsp.vector_fmul(chunk + block_size * j,

447 chunk + block_size * j,

448 tctx->tmp_buf, block_size);

449 }

450

451 if (ftype == TWINVQ_FT_LONG)

452 tctx->decode_ppc(tctx, bits->p_coef[i], bits->g_coef[i],

453 ppc_shape + i * mtab->ppc_shape_len, chunk);

454

455 decode_lsp(tctx, bits->lpc_idx1[i], bits->lpc_idx2[i],

456 bits->lpc_hist_idx[i], lsp, tctx->lsp_hist[i]);

457

458 dec_lpc_spectrum_inv(tctx, lsp, ftype, tctx->tmp_buf);

459

460 for (j = 0; j < mtab->fmode[ftype].sub; j++) {

461 tctx->fdsp.vector_fmul(chunk, chunk, tctx->tmp_buf, block_size);

462 chunk += block_size;

463 }

464 }

465 }

466

467 const enum TwinVQFrameType ff_twinvq_wtype_to_ftype_table[] = {

468 TWINVQ_FT_LONG, TWINVQ_FT_LONG, TWINVQ_FT_SHORT, TWINVQ_FT_LONG,

469 TWINVQ_FT_MEDIUM, TWINVQ_FT_LONG, TWINVQ_FT_LONG, TWINVQ_FT_MEDIUM,

470 TWINVQ_FT_MEDIUM

471 };

472

473 int ff_twinvq_decode_frame(AVCodecContext *avctx, void *data,

474 int *got_frame_ptr, AVPacket *avpkt)

475 {

476 AVFrame *frame = data;

477 const uint8_t *buf = avpkt->data;

478 int buf_size = avpkt->size;

479 TwinVQContext *tctx = avctx->priv_data;

480 const TwinVQModeTab *mtab = tctx->mtab;

481 float **out = NULL;

482 int ret;

483

484 /* get output buffer */

485 if (tctx->discarded_packets >= 2) {

486 frame->nb_samples = mtab->size;

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

488 return ret;

489 out = (float **)frame->extended_data;

490 }

491

492 if (buf_size < avctx->block_align) {

493 av_log(avctx, AV_LOG_ERROR,

494 "Frame too small (%d bytes). Truncated file?\n", buf_size);

495 return AVERROR(EINVAL);

496 }

497

498 if ((ret = tctx->read_bitstream(avctx, tctx, buf, buf_size)) < 0)

499 return ret;

500

501 read_and_decode_spectrum(tctx, tctx->spectrum, tctx->bits.ftype);

502

503 imdct_output(tctx, tctx->bits.ftype, tctx->bits.window_type, out);

504

505 FFSWAP(float *, tctx->curr_frame, tctx->prev_frame);

506

507 if (tctx->discarded_packets < 2) {

508 tctx->discarded_packets++;

509 *got_frame_ptr = 0;

510 return buf_size;

511 }

512

513 *got_frame_ptr = 1;

514

515 return ret;

516 }

517

518 /**

519 * Init IMDCT and windowing tables

520 */

521 static av_cold int init_mdct_win(TwinVQContext *tctx)

522 {

523 int i, j, ret;

524 const TwinVQModeTab *mtab = tctx->mtab;

525 int size_s = mtab->size / mtab->fmode[TWINVQ_FT_SHORT].sub;

526 int size_m = mtab->size / mtab->fmode[TWINVQ_FT_MEDIUM].sub;

527 int channels = tctx->avctx->channels;

528 float norm = channels == 1 ? 2.0 : 1.0;

529

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

531 int bsize = tctx->mtab->size / tctx->mtab->fmode[i].sub;

532 if ((ret = ff_mdct_init(&tctx->mdct_ctx[i], av_log2(bsize) + 1, 1,

533 -sqrt(norm / bsize) / (1 << 15))))

534 return ret;

535 }

536

537 FF_ALLOC_OR_GOTO(tctx->avctx, tctx->tmp_buf,

538 mtab->size * sizeof(*tctx->tmp_buf), alloc_fail);

539

540 FF_ALLOC_OR_GOTO(tctx->avctx, tctx->spectrum,

541 2 * mtab->size * channels * sizeof(*tctx->spectrum),

542 alloc_fail);

543 FF_ALLOC_OR_GOTO(tctx->avctx, tctx->curr_frame,

544 2 * mtab->size * channels * sizeof(*tctx->curr_frame),

545 alloc_fail);

546 FF_ALLOC_OR_GOTO(tctx->avctx, tctx->prev_frame,

547 2 * mtab->size * channels * sizeof(*tctx->prev_frame),

548 alloc_fail);

549

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

551 int m = 4 * mtab->size / mtab->fmode[i].sub;

552 double freq = 2 * M_PI / m;

553 FF_ALLOC_OR_GOTO(tctx->avctx, tctx->cos_tabs[i],

554 (m / 4) * sizeof(*tctx->cos_tabs[i]), alloc_fail);

555

556 for (j = 0; j <= m / 8; j++)

557 tctx->cos_tabs[i][j] = cos((2 * j + 1) * freq);

558 for (j = 1; j < m / 8; j++)

559 tctx->cos_tabs[i][m / 4 - j] = tctx->cos_tabs[i][j];

560 }

561

562 ff_init_ff_sine_windows(av_log2(size_m));

563 ff_init_ff_sine_windows(av_log2(size_s / 2));

564 ff_init_ff_sine_windows(av_log2(mtab->size));

565

566 return 0;

567

568 alloc_fail:

569 return AVERROR(ENOMEM);

570 }

571

572 /**

573 * Interpret the data as if it were a num_blocks x line_len[0] matrix and for

574 * each line do a cyclic permutation, i.e.

575 * abcdefghijklm -> defghijklmabc

576 * where the amount to be shifted is evaluated depending on the column.

577 */

578 static void permutate_in_line(int16_t *tab, int num_vect, int num_blocks,

579 int block_size,

580 const uint8_t line_len[2], int length_div,

581 enum TwinVQFrameType ftype)

582 {

583 int i, j;

584

585 for (i = 0; i < line_len[0]; i++) {

586 int shift;

587

588 if (num_blocks == 1 ||

589 (ftype == TWINVQ_FT_LONG && num_vect % num_blocks) ||

590 (ftype != TWINVQ_FT_LONG && num_vect & 1) ||

591 i == line_len[1]) {

592 shift = 0;

593 } else if (ftype == TWINVQ_FT_LONG) {

594 shift = i;

595 } else

596 shift = i * i;

597

598 for (j = 0; j < num_vect && (j + num_vect * i < block_size * num_blocks); j++)

599 tab[i * num_vect + j] = i * num_vect + (j + shift) % num_vect;

600 }

601 }

602

603 /**

604 * Interpret the input data as in the following table:

605 *

606 * @verbatim

607 *

608 * abcdefgh

609 * ijklmnop

610 * qrstuvw

611 * x123456

612 *

613 * @endverbatim

614 *

615 * and transpose it, giving the output

616 * aiqxbjr1cks2dlt3emu4fvn5gow6hp

617 */

618 static void transpose_perm(int16_t *out, int16_t *in, int num_vect,

619 const uint8_t line_len[2], int length_div)

620 {

621 int i, j;

622 int cont = 0;

623

624 for (i = 0; i < num_vect; i++)

625 for (j = 0; j < line_len[i >= length_div]; j++)

626 out[cont++] = in[j * num_vect + i];

627 }

628

629 static void linear_perm(int16_t *out, int16_t *in, int n_blocks, int size)

630 {

631 int block_size = size / n_blocks;

632 int i;

633

634 for (i = 0; i < size; i++)

635 out[i] = block_size * (in[i] % n_blocks) + in[i] / n_blocks;

636 }

637

638 static av_cold void construct_perm_table(TwinVQContext *tctx,

639 enum TwinVQFrameType ftype)

640 {

641 int block_size, size;

642 const TwinVQModeTab *mtab = tctx->mtab;

643 int16_t *tmp_perm = (int16_t *)tctx->tmp_buf;

644

645 if (ftype == TWINVQ_FT_PPC) {

646 size = tctx->avctx->channels;

647 block_size = mtab->ppc_shape_len;

648 } else {

649 size = tctx->avctx->channels * mtab->fmode[ftype].sub;

650 block_size = mtab->size / mtab->fmode[ftype].sub;

651 }

652

653 permutate_in_line(tmp_perm, tctx->n_div[ftype], size,

654 block_size, tctx->length[ftype],

655 tctx->length_change[ftype], ftype);

656

657 transpose_perm(tctx->permut[ftype], tmp_perm, tctx->n_div[ftype],

658 tctx->length[ftype], tctx->length_change[ftype]);

659

660 linear_perm(tctx->permut[ftype], tctx->permut[ftype], size,

661 size * block_size);

662 }

663

664 static av_cold void init_bitstream_params(TwinVQContext *tctx)

665 {

666 const TwinVQModeTab *mtab = tctx->mtab;

667 int n_ch = tctx->avctx->channels;

668 int total_fr_bits = tctx->avctx->bit_rate * mtab->size /

669 tctx->avctx->sample_rate;

670

671 int lsp_bits_per_block = n_ch * (mtab->lsp_bit0 + mtab->lsp_bit1 +

672 mtab->lsp_split * mtab->lsp_bit2);

673

674 int ppc_bits = n_ch * (mtab->pgain_bit + mtab->ppc_shape_bit +

675 mtab->ppc_period_bit);

676

677 int bsize_no_main_cb[3], bse_bits[3], i;

678 enum TwinVQFrameType frametype;

679

680 for (i = 0; i < 3; i++)

681 // +1 for history usage switch

682 bse_bits[i] = n_ch *

683 (mtab->fmode[i].bark_n_coef *

684 mtab->fmode[i].bark_n_bit + 1);

685

686 bsize_no_main_cb[2] = bse_bits[2] + lsp_bits_per_block + ppc_bits +

687 TWINVQ_WINDOW_TYPE_BITS + n_ch * TWINVQ_GAIN_BITS;

688

689 for (i = 0; i < 2; i++)

690 bsize_no_main_cb[i] =

691 lsp_bits_per_block + n_ch * TWINVQ_GAIN_BITS +

692 TWINVQ_WINDOW_TYPE_BITS +

693 mtab->fmode[i].sub * (bse_bits[i] + n_ch * TWINVQ_SUB_GAIN_BITS);

694

695 if (tctx->codec == TWINVQ_CODEC_METASOUND) {

696 bsize_no_main_cb[1] += 2;

697 bsize_no_main_cb[2] += 2;

698 }

699

700 // The remaining bits are all used for the main spectrum coefficients

701 for (i = 0; i < 4; i++) {

702 int bit_size, vect_size;

703 int rounded_up, rounded_down, num_rounded_down, num_rounded_up;

704 if (i == 3) {

705 bit_size = n_ch * mtab->ppc_shape_bit;

706 vect_size = n_ch * mtab->ppc_shape_len;

707 } else {

708 bit_size = total_fr_bits - bsize_no_main_cb[i];

709 vect_size = n_ch * mtab->size;

710 }

711

712 tctx->n_div[i] = (bit_size + 13) / 14;

713

714 rounded_up = (bit_size + tctx->n_div[i] - 1) /

715 tctx->n_div[i];

716 rounded_down = (bit_size) / tctx->n_div[i];

717 num_rounded_down = rounded_up * tctx->n_div[i] - bit_size;

718 num_rounded_up = tctx->n_div[i] - num_rounded_down;

719 tctx->bits_main_spec[0][i][0] = (rounded_up + 1) / 2;

720 tctx->bits_main_spec[1][i][0] = rounded_up / 2;

721 tctx->bits_main_spec[0][i][1] = (rounded_down + 1) / 2;

722 tctx->bits_main_spec[1][i][1] = rounded_down / 2;

723 tctx->bits_main_spec_change[i] = num_rounded_up;

724

725 rounded_up = (vect_size + tctx->n_div[i] - 1) /

726 tctx->n_div[i];

727 rounded_down = (vect_size) / tctx->n_div[i];

728 num_rounded_down = rounded_up * tctx->n_div[i] - vect_size;

729 num_rounded_up = tctx->n_div[i] - num_rounded_down;

730 tctx->length[i][0] = rounded_up;

731 tctx->length[i][1] = rounded_down;

732 tctx->length_change[i] = num_rounded_up;

733 }

734

735 for (frametype = TWINVQ_FT_SHORT; frametype <= TWINVQ_FT_PPC; frametype++)

736 construct_perm_table(tctx, frametype);

737 }

738

739 av_cold int ff_twinvq_decode_close(AVCodecContext *avctx)

740 {

741 TwinVQContext *tctx = avctx->priv_data;

742 int i;

743

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

745 ff_mdct_end(&tctx->mdct_ctx[i]);

746 av_free(tctx->cos_tabs[i]);

747 }

748

749 av_free(tctx->curr_frame);

750 av_free(tctx->spectrum);

751 av_free(tctx->prev_frame);

752 av_free(tctx->tmp_buf);

753

754 return 0;

755 }

756

757 av_cold int ff_twinvq_decode_init(AVCodecContext *avctx)

758 {

759 int ret;

760 TwinVQContext *tctx = avctx->priv_data;

761

762 tctx->avctx = avctx;

763 avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;

764

765 avpriv_float_dsp_init(&tctx->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);

766 if ((ret = init_mdct_win(tctx))) {

767 av_log(avctx, AV_LOG_ERROR, "Error initializing MDCT\n");

768 ff_twinvq_decode_close(avctx);

769 return ret;

770 }

771 init_bitstream_params(tctx);

772

773 twinvq_memset_float(tctx->bark_hist[0][0], 0.1,

774 FF_ARRAY_ELEMS(tctx->bark_hist));

775

776 return 0;

777 }

Generated on Sat Jan 25 2014 19:51:55 for FFmpeg by doxygen 1.8.2