FFmpeg: libavcodec/imc.c Source File

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imc.c

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1 /*

2 * IMC compatible decoder

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 /**

25 * @file

26 * IMC - Intel Music Coder

27 * A mdct based codec using a 256 points large transform

28 * divided into 32 bands with some mix of scale factors.

29 * Only mono is supported.

30 *

31 */

34 #include <math.h>

35 #include <stddef.h>

36 #include <stdio.h>

38 #include "libavutil/channel_layout.h"

39 #include "libavutil/float_dsp.h"

40 #include "libavutil/internal.h"

41 #include "libavutil/libm.h"

42 #include "avcodec.h"

43 #include "bswapdsp.h"

44 #include "get_bits.h"

45 #include "fft.h"

46 #include "internal.h"

47 #include "sinewin.h"

49 #include "imcdata.h"

51 #define IMC_BLOCK_SIZE 64

52 #define IMC_FRAME_ID 0x21

53 #define BANDS 32

54 #define COEFFS 256

56 typedef struct IMCChannel {

57 float old_floor[BANDS];

58 float flcoeffs1[BANDS];

59 float flcoeffs2[BANDS];

60 float flcoeffs3[BANDS];

61 float flcoeffs4[BANDS];

62 float flcoeffs5[BANDS];

63 float flcoeffs6[BANDS];

64 float CWdecoded[COEFFS];

66 int bandWidthT[BANDS]; ///< codewords per band

67 int bitsBandT[BANDS]; ///< how many bits per codeword in band

68 int CWlengthT[COEFFS]; ///< how many bits in each codeword

69 int levlCoeffBuf[BANDS];

70 int bandFlagsBuf[BANDS]; ///< flags for each band

71 int sumLenArr[BANDS]; ///< bits for all coeffs in band

72 int skipFlagRaw[BANDS]; ///< skip flags are stored in raw form or not

73 int skipFlagBits[BANDS]; ///< bits used to code skip flags

74 int skipFlagCount[BANDS]; ///< skipped coeffients per band

75 int skipFlags[COEFFS]; ///< skip coefficient decoding or not

76 int codewords[COEFFS]; ///< raw codewords read from bitstream

78 float last_fft_im[COEFFS];

80 int decoder_reset;

81 } IMCChannel;

83 typedef struct IMCContext {

84 IMCChannel chctx[2];

86 /** MDCT tables */

87 //@{

88 float mdct_sine_window[COEFFS];

89 float post_cos[COEFFS];

90 float post_sin[COEFFS];

91 float pre_coef1[COEFFS];

92 float pre_coef2[COEFFS];

93 //@}

95 float sqrt_tab[30];

96 GetBitContext gb;

98 BswapDSPContext bdsp;

99 AVFloatDSPContext *fdsp;

100 FFTContext fft;

101 DECLARE_ALIGNED(32, FFTComplex, samples)[COEFFS / 2];

102 float *out_samples;

103

104 int coef0_pos;

105

106 int8_t cyclTab[32], cyclTab2[32];

107 float weights1[31], weights2[31];

108 } IMCContext;

109

110 static VLC huffman_vlc[4][4];

111

112 #define VLC_TABLES_SIZE 9512

113

114 static const int vlc_offsets[17] = {

115 0, 640, 1156, 1732, 2308, 2852, 3396, 3924,

116 4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE

117 };

118

119 static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];

120

121 static inline double freq2bark(double freq)

122 {

123 return 3.5 * atan((freq / 7500.0) * (freq / 7500.0)) + 13.0 * atan(freq * 0.00076);

124 }

125

126 static av_cold void iac_generate_tabs(IMCContext *q, int sampling_rate)

127 {

128 double freqmin[32], freqmid[32], freqmax[32];

129 double scale = sampling_rate / (256.0 * 2.0 * 2.0);

130 double nyquist_freq = sampling_rate * 0.5;

131 double freq, bark, prev_bark = 0, tf, tb;

132 int i, j;

133

134 for (i = 0; i < 32; i++) {

135 freq = (band_tab[i] + band_tab[i + 1] - 1) * scale;

136 bark = freq2bark(freq);

137

138 if (i > 0) {

139 tb = bark - prev_bark;

140 q->weights1[i - 1] = pow(10.0, -1.0 * tb);

141 q->weights2[i - 1] = pow(10.0, -2.7 * tb);

142 }

143 prev_bark = bark;

144

145 freqmid[i] = freq;

146

147 tf = freq;

148 while (tf < nyquist_freq) {

149 tf += 0.5;

150 tb = freq2bark(tf);

151 if (tb > bark + 0.5)

152 break;

153 }

154 freqmax[i] = tf;

155

156 tf = freq;

157 while (tf > 0.0) {

158 tf -= 0.5;

159 tb = freq2bark(tf);

160 if (tb <= bark - 0.5)

161 break;

162 }

163 freqmin[i] = tf;

164 }

165

166 for (i = 0; i < 32; i++) {

167 freq = freqmax[i];

168 for (j = 31; j > 0 && freq <= freqmid[j]; j--);

169 q->cyclTab[i] = j + 1;

170

171 freq = freqmin[i];

172 for (j = 0; j < 32 && freq >= freqmid[j]; j++);

173 q->cyclTab2[i] = j - 1;

174 }

175 }

176

177 static av_cold int imc_decode_init(AVCodecContext *avctx)

178 {

179 int i, j, ret;

180 IMCContext *q = avctx->priv_data;

181 double r1, r2;

182

183 if (avctx->codec_id == AV_CODEC_ID_IAC && avctx->sample_rate > 96000) {

184 av_log(avctx, AV_LOG_ERROR,

185 "Strange sample rate of %i, file likely corrupt or "

186 "needing a new table derivation method.\n",

187 avctx->sample_rate);

188 return AVERROR_PATCHWELCOME;

189 }

190

191 if (avctx->codec_id == AV_CODEC_ID_IMC)

192 avctx->channels = 1;

193

194 if (avctx->channels > 2) {

195 avpriv_request_sample(avctx, "Number of channels > 2");

196 return AVERROR_PATCHWELCOME;

197 }

198

199 for (j = 0; j < avctx->channels; j++) {

200 q->chctx[j].decoder_reset = 1;

201

202 for (i = 0; i < BANDS; i++)

203 q->chctx[j].old_floor[i] = 1.0;

204

205 for (i = 0; i < COEFFS / 2; i++)

206 q->chctx[j].last_fft_im[i] = 0;

207 }

208

209 /* Build mdct window, a simple sine window normalized with sqrt(2) */

210 ff_sine_window_init(q->mdct_sine_window, COEFFS);

211 for (i = 0; i < COEFFS; i++)

212 q->mdct_sine_window[i] *= sqrt(2.0);

213 for (i = 0; i < COEFFS / 2; i++) {

214 q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);

215 q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);

216

217 r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);

218 r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);

219

220 if (i & 0x1) {

221 q->pre_coef1[i] = (r1 + r2) * sqrt(2.0);

222 q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);

223 } else {

224 q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);

225 q->pre_coef2[i] = (r1 - r2) * sqrt(2.0);

226 }

227 }

228

229 /* Generate a square root table */

230

231 for (i = 0; i < 30; i++)

232 q->sqrt_tab[i] = sqrt(i);

233

234 /* initialize the VLC tables */

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

236 for (j = 0; j < 4; j++) {

237 huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];

238 huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];

239 init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],

240 imc_huffman_lens[i][j], 1, 1,

241 imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);

242 }

243 }

244

245 if (avctx->codec_id == AV_CODEC_ID_IAC) {

246 iac_generate_tabs(q, avctx->sample_rate);

247 } else {

248 memcpy(q->cyclTab, cyclTab, sizeof(cyclTab));

249 memcpy(q->cyclTab2, cyclTab2, sizeof(cyclTab2));

250 memcpy(q->weights1, imc_weights1, sizeof(imc_weights1));

251 memcpy(q->weights2, imc_weights2, sizeof(imc_weights2));

252 }

253

254 if ((ret = ff_fft_init(&q->fft, 7, 1))) {

255 av_log(avctx, AV_LOG_INFO, "FFT init failed\n");

256 return ret;

257 }

258 ff_bswapdsp_init(&q->bdsp);

259 q->fdsp = avpriv_float_dsp_alloc(avctx->flags & CODEC_FLAG_BITEXACT);

260 if (!q->fdsp) {

261 ff_fft_end(&q->fft);

262

263 return AVERROR(ENOMEM);

264 }

265

266 avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;

267 avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO

268 : AV_CH_LAYOUT_STEREO;

269

270 return 0;

271 }

272

273 static void imc_calculate_coeffs(IMCContext *q, float *flcoeffs1,

274 float *flcoeffs2, int *bandWidthT,

275 float *flcoeffs3, float *flcoeffs5)

276 {

277 float workT1[BANDS];

278 float workT2[BANDS];

279 float workT3[BANDS];

280 float snr_limit = 1.e-30;

281 float accum = 0.0;

282 int i, cnt2;

283

284 for (i = 0; i < BANDS; i++) {

285 flcoeffs5[i] = workT2[i] = 0.0;

286 if (bandWidthT[i]) {

287 workT1[i] = flcoeffs1[i] * flcoeffs1[i];

288 flcoeffs3[i] = 2.0 * flcoeffs2[i];

289 } else {

290 workT1[i] = 0.0;

291 flcoeffs3[i] = -30000.0;

292 }

293 workT3[i] = bandWidthT[i] * workT1[i] * 0.01;

294 if (workT3[i] <= snr_limit)

295 workT3[i] = 0.0;

296 }

297

298 for (i = 0; i < BANDS; i++) {

299 for (cnt2 = i; cnt2 < q->cyclTab[i]; cnt2++)

300 flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];

301 workT2[cnt2 - 1] = workT2[cnt2 - 1] + workT3[i];

302 }

303

304 for (i = 1; i < BANDS; i++) {

305 accum = (workT2[i - 1] + accum) * q->weights1[i - 1];

306 flcoeffs5[i] += accum;

307 }

308

309 for (i = 0; i < BANDS; i++)

310 workT2[i] = 0.0;

311

312 for (i = 0; i < BANDS; i++) {

313 for (cnt2 = i - 1; cnt2 > q->cyclTab2[i]; cnt2--)

314 flcoeffs5[cnt2] += workT3[i];

315 workT2[cnt2+1] += workT3[i];

316 }

317

318 accum = 0.0;

319

320 for (i = BANDS-2; i >= 0; i--) {

321 accum = (workT2[i+1] + accum) * q->weights2[i];

322 flcoeffs5[i] += accum;

323 // there is missing code here, but it seems to never be triggered

324 }

325 }

326

327

328 static void imc_read_level_coeffs(IMCContext *q, int stream_format_code,

329 int *levlCoeffs)

330 {

331 int i;

332 VLC *hufftab[4];

333 int start = 0;

334 const uint8_t *cb_sel;

335 int s;

336

337 s = stream_format_code >> 1;

338 hufftab[0] = &huffman_vlc[s][0];

339 hufftab[1] = &huffman_vlc[s][1];

340 hufftab[2] = &huffman_vlc[s][2];

341 hufftab[3] = &huffman_vlc[s][3];

342 cb_sel = imc_cb_select[s];

343

344 if (stream_format_code & 4)

345 start = 1;

346 if (start)

347 levlCoeffs[0] = get_bits(&q->gb, 7);

348 for (i = start; i < BANDS; i++) {

349 levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table,

350 hufftab[cb_sel[i]]->bits, 2);

351 if (levlCoeffs[i] == 17)

352 levlCoeffs[i] += get_bits(&q->gb, 4);

353 }

354 }

355

356 static void imc_read_level_coeffs_raw(IMCContext *q, int stream_format_code,

357 int *levlCoeffs)

358 {

359 int i;

360

361 q->coef0_pos = get_bits(&q->gb, 5);

362 levlCoeffs[0] = get_bits(&q->gb, 7);

363 for (i = 1; i < BANDS; i++)

364 levlCoeffs[i] = get_bits(&q->gb, 4);

365 }

366

367 static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,

368 float *flcoeffs1, float *flcoeffs2)

369 {

370 int i, level;

371 float tmp, tmp2;

372 // maybe some frequency division thingy

373

374 flcoeffs1[0] = 20000.0 / exp2 (levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125

375 flcoeffs2[0] = log2f(flcoeffs1[0]);

376 tmp = flcoeffs1[0];

377 tmp2 = flcoeffs2[0];

378

379 for (i = 1; i < BANDS; i++) {

380 level = levlCoeffBuf[i];

381 if (level == 16) {

382 flcoeffs1[i] = 1.0;

383 flcoeffs2[i] = 0.0;

384 } else {

385 if (level < 17)

386 level -= 7;

387 else if (level <= 24)

388 level -= 32;

389 else

390 level -= 16;

391

392 tmp *= imc_exp_tab[15 + level];

393 tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25

394 flcoeffs1[i] = tmp;

395 flcoeffs2[i] = tmp2;

396 }

397 }

398 }

399

400

401 static void imc_decode_level_coefficients2(IMCContext *q, int *levlCoeffBuf,

402 float *old_floor, float *flcoeffs1,

403 float *flcoeffs2)

404 {

405 int i;

406 /* FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors

407 * and flcoeffs2 old scale factors

408 * might be incomplete due to a missing table that is in the binary code

409 */

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

411 flcoeffs1[i] = 0;

412 if (levlCoeffBuf[i] < 16) {

413 flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];

414 flcoeffs2[i] = (levlCoeffBuf[i] - 7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25

415 } else {

416 flcoeffs1[i] = old_floor[i];

417 }

418 }

419 }

420

421 static void imc_decode_level_coefficients_raw(IMCContext *q, int *levlCoeffBuf,

422 float *flcoeffs1, float *flcoeffs2)

423 {

424 int i, level, pos;

425 float tmp, tmp2;

426

427 pos = q->coef0_pos;

428 flcoeffs1[pos] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125

429 flcoeffs2[pos] = log2f(flcoeffs1[0]);

430 tmp = flcoeffs1[pos];

431 tmp2 = flcoeffs2[pos];

432

433 levlCoeffBuf++;

434 for (i = 0; i < BANDS; i++) {

435 if (i == pos)

436 continue;

437 level = *levlCoeffBuf++;

438 flcoeffs1[i] = tmp * powf(10.0, -level * 0.4375); //todo tab

439 flcoeffs2[i] = tmp2 - 1.4533435415 * level; // 1.4533435415 = log2(10) * 0.4375

440 }

441 }

442

443 /**

444 * Perform bit allocation depending on bits available

445 */

446 static int bit_allocation(IMCContext *q, IMCChannel *chctx,

447 int stream_format_code, int freebits, int flag)

448 {

449 int i, j;

450 const float limit = -1.e20;

451 float highest = 0.0;

452 int indx;

453 int t1 = 0;

454 int t2 = 1;

455 float summa = 0.0;

456 int iacc = 0;

457 int summer = 0;

458 int rres, cwlen;

459 float lowest = 1.e10;

460 int low_indx = 0;

461 float workT[32];

462 int flg;

463 int found_indx = 0;

464

465 for (i = 0; i < BANDS; i++)

466 highest = FFMAX(highest, chctx->flcoeffs1[i]);

467

468 for (i = 0; i < BANDS - 1; i++) {

469 if (chctx->flcoeffs5[i] <= 0) {

470 av_log(NULL, AV_LOG_ERROR, "flcoeffs5 %f invalid\n", chctx->flcoeffs5[i]);

471 return AVERROR_INVALIDDATA;

472 }

473 chctx->flcoeffs4[i] = chctx->flcoeffs3[i] - log2f(chctx->flcoeffs5[i]);

474 }

475 chctx->flcoeffs4[BANDS - 1] = limit;

476

477 highest = highest * 0.25;

478

479 for (i = 0; i < BANDS; i++) {

480 indx = -1;

481 if ((band_tab[i + 1] - band_tab[i]) == chctx->bandWidthT[i])

482 indx = 0;

483

484 if ((band_tab[i + 1] - band_tab[i]) > chctx->bandWidthT[i])

485 indx = 1;

486

487 if (((band_tab[i + 1] - band_tab[i]) / 2) >= chctx->bandWidthT[i])

488 indx = 2;

489

490 if (indx == -1)

491 return AVERROR_INVALIDDATA;

492

493 chctx->flcoeffs4[i] += xTab[(indx * 2 + (chctx->flcoeffs1[i] < highest)) * 2 + flag];

494 }

495

496 if (stream_format_code & 0x2) {

497 chctx->flcoeffs4[0] = limit;

498 chctx->flcoeffs4[1] = limit;

499 chctx->flcoeffs4[2] = limit;

500 chctx->flcoeffs4[3] = limit;

501 }

502

503 for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS - 1; i++) {

504 iacc += chctx->bandWidthT[i];

505 summa += chctx->bandWidthT[i] * chctx->flcoeffs4[i];

506 }

507

508 if (!iacc)

509 return AVERROR_INVALIDDATA;

510

511 chctx->bandWidthT[BANDS - 1] = 0;

512 summa = (summa * 0.5 - freebits) / iacc;

513

514

515 for (i = 0; i < BANDS / 2; i++) {

516 rres = summer - freebits;

517 if ((rres >= -8) && (rres <= 8))

518 break;

519

520 summer = 0;

521 iacc = 0;

522

523 for (j = (stream_format_code & 0x2) ? 4 : 0; j < BANDS; j++) {

524 cwlen = av_clipf(((chctx->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);

525

526 chctx->bitsBandT[j] = cwlen;

527 summer += chctx->bandWidthT[j] * cwlen;

528

529 if (cwlen > 0)

530 iacc += chctx->bandWidthT[j];

531 }

532

533 flg = t2;

534 t2 = 1;

535 if (freebits < summer)

536 t2 = -1;

537 if (i == 0)

538 flg = t2;

539 if (flg != t2)

540 t1++;

541

542 summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;

543 }

544

545 for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS; i++) {

546 for (j = band_tab[i]; j < band_tab[i + 1]; j++)

547 chctx->CWlengthT[j] = chctx->bitsBandT[i];

548 }

549

550 if (freebits > summer) {

551 for (i = 0; i < BANDS; i++) {

552 workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20

553 : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);

554 }

555

556 highest = 0.0;

557

558 do {

559 if (highest <= -1.e20)

560 break;

561

562 found_indx = 0;

563 highest = -1.e20;

564

565 for (i = 0; i < BANDS; i++) {

566 if (workT[i] > highest) {

567 highest = workT[i];

568 found_indx = i;

569 }

570 }

571

572 if (highest > -1.e20) {

573 workT[found_indx] -= 2.0;

574 if (++chctx->bitsBandT[found_indx] == 6)

575 workT[found_indx] = -1.e20;

576

577 for (j = band_tab[found_indx]; j < band_tab[found_indx + 1] && (freebits > summer); j++) {

578 chctx->CWlengthT[j]++;

579 summer++;

580 }

581 }

582 } while (freebits > summer);

583 }

584 if (freebits < summer) {

585 for (i = 0; i < BANDS; i++) {

586 workT[i] = chctx->bitsBandT[i] ? (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] + 1.585)

587 : 1.e20;

588 }

589 if (stream_format_code & 0x2) {

590 workT[0] = 1.e20;

591 workT[1] = 1.e20;

592 workT[2] = 1.e20;

593 workT[3] = 1.e20;

594 }

595 while (freebits < summer) {

596 lowest = 1.e10;

597 low_indx = 0;

598 for (i = 0; i < BANDS; i++) {

599 if (workT[i] < lowest) {

600 lowest = workT[i];

601 low_indx = i;

602 }

603 }

604 // if (lowest >= 1.e10)

605 // break;

606 workT[low_indx] = lowest + 2.0;

607

608 if (!--chctx->bitsBandT[low_indx])

609 workT[low_indx] = 1.e20;

610

611 for (j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++) {

612 if (chctx->CWlengthT[j] > 0) {

613 chctx->CWlengthT[j]--;

614 summer--;

615 }

616 }

617 }

618 }

619 return 0;

620 }

621

622 static void imc_get_skip_coeff(IMCContext *q, IMCChannel *chctx)

623 {

624 int i, j;

625

626 memset(chctx->skipFlagBits, 0, sizeof(chctx->skipFlagBits));

627 memset(chctx->skipFlagCount, 0, sizeof(chctx->skipFlagCount));

628 for (i = 0; i < BANDS; i++) {

629 if (!chctx->bandFlagsBuf[i] || !chctx->bandWidthT[i])

630 continue;

631

632 if (!chctx->skipFlagRaw[i]) {

633 chctx->skipFlagBits[i] = band_tab[i + 1] - band_tab[i];

634

635 for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

636 chctx->skipFlags[j] = get_bits1(&q->gb);

637 if (chctx->skipFlags[j])

638 chctx->skipFlagCount[i]++;

639 }

640 } else {

641 for (j = band_tab[i]; j < band_tab[i + 1] - 1; j += 2) {

642 if (!get_bits1(&q->gb)) { // 0

643 chctx->skipFlagBits[i]++;

644 chctx->skipFlags[j] = 1;

645 chctx->skipFlags[j + 1] = 1;

646 chctx->skipFlagCount[i] += 2;

647 } else {

648 if (get_bits1(&q->gb)) { // 11

649 chctx->skipFlagBits[i] += 2;

650 chctx->skipFlags[j] = 0;

651 chctx->skipFlags[j + 1] = 1;

652 chctx->skipFlagCount[i]++;

653 } else {

654 chctx->skipFlagBits[i] += 3;

655 chctx->skipFlags[j + 1] = 0;

656 if (!get_bits1(&q->gb)) { // 100

657 chctx->skipFlags[j] = 1;

658 chctx->skipFlagCount[i]++;

659 } else { // 101

660 chctx->skipFlags[j] = 0;

661 }

662 }

663 }

664 }

665

666 if (j < band_tab[i + 1]) {

667 chctx->skipFlagBits[i]++;

668 if ((chctx->skipFlags[j] = get_bits1(&q->gb)))

669 chctx->skipFlagCount[i]++;

670 }

671 }

672 }

673 }

674

675 /**

676 * Increase highest' band coefficient sizes as some bits won't be used

677 */

678 static void imc_adjust_bit_allocation(IMCContext *q, IMCChannel *chctx,

679 int summer)

680 {

681 float workT[32];

682 int corrected = 0;

683 int i, j;

684 float highest = 0;

685 int found_indx = 0;

686

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

688 workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20

689 : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);

690 }

691

692 while (corrected < summer) {

693 if (highest <= -1.e20)

694 break;

695

696 highest = -1.e20;

697

698 for (i = 0; i < BANDS; i++) {

699 if (workT[i] > highest) {

700 highest = workT[i];

701 found_indx = i;

702 }

703 }

704

705 if (highest > -1.e20) {

706 workT[found_indx] -= 2.0;

707 if (++(chctx->bitsBandT[found_indx]) == 6)

708 workT[found_indx] = -1.e20;

709

710 for (j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {

711 if (!chctx->skipFlags[j] && (chctx->CWlengthT[j] < 6)) {

712 chctx->CWlengthT[j]++;

713 corrected++;

714 }

715 }

716 }

717 }

718 }

719

720 static void imc_imdct256(IMCContext *q, IMCChannel *chctx, int channels)

721 {

722 int i;

723 float re, im;

724 float *dst1 = q->out_samples;

725 float *dst2 = q->out_samples + (COEFFS - 1);

726

727 /* prerotation */

728 for (i = 0; i < COEFFS / 2; i++) {

729 q->samples[i].re = -(q->pre_coef1[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -

730 (q->pre_coef2[i] * chctx->CWdecoded[i * 2]);

731 q->samples[i].im = (q->pre_coef2[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -

732 (q->pre_coef1[i] * chctx->CWdecoded[i * 2]);

733 }

734

735 /* FFT */

736 q->fft.fft_permute(&q->fft, q->samples);

737 q->fft.fft_calc(&q->fft, q->samples);

738

739 /* postrotation, window and reorder */

740 for (i = 0; i < COEFFS / 2; i++) {

741 re = ( q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);

742 im = (-q->samples[i].im * q->post_cos[i]) - ( q->samples[i].re * q->post_sin[i]);

743 *dst1 = (q->mdct_sine_window[COEFFS - 1 - i * 2] * chctx->last_fft_im[i])

744 + (q->mdct_sine_window[i * 2] * re);

745 *dst2 = (q->mdct_sine_window[i * 2] * chctx->last_fft_im[i])

746 - (q->mdct_sine_window[COEFFS - 1 - i * 2] * re);

747 dst1 += 2;

748 dst2 -= 2;

749 chctx->last_fft_im[i] = im;

750 }

751 }

752

753 static int inverse_quant_coeff(IMCContext *q, IMCChannel *chctx,

754 int stream_format_code)

755 {

756 int i, j;

757 int middle_value, cw_len, max_size;

758 const float *quantizer;

759

760 for (i = 0; i < BANDS; i++) {

761 for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

762 chctx->CWdecoded[j] = 0;

763 cw_len = chctx->CWlengthT[j];

764

765 if (cw_len <= 0 || chctx->skipFlags[j])

766 continue;

767

768 max_size = 1 << cw_len;

769 middle_value = max_size >> 1;

770

771 if (chctx->codewords[j] >= max_size || chctx->codewords[j] < 0)

772 return AVERROR_INVALIDDATA;

773

774 if (cw_len >= 4) {

775 quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];

776 if (chctx->codewords[j] >= middle_value)

777 chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 8] * chctx->flcoeffs6[i];

778 else

779 chctx->CWdecoded[j] = -quantizer[max_size - chctx->codewords[j] - 8 - 1] * chctx->flcoeffs6[i];

780 }else{

781 quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (chctx->bandFlagsBuf[i] << 1)];

782 if (chctx->codewords[j] >= middle_value)

783 chctx->CWdecoded[j] = quantizer[chctx->codewords[j] - 1] * chctx->flcoeffs6[i];

784 else

785 chctx->CWdecoded[j] = -quantizer[max_size - 2 - chctx->codewords[j]] * chctx->flcoeffs6[i];

786 }

787 }

788 }

789 return 0;

790 }

791

792

793 static void imc_get_coeffs(AVCodecContext *avctx,

794 IMCContext *q, IMCChannel *chctx)

795 {

796 int i, j, cw_len, cw;

797

798 for (i = 0; i < BANDS; i++) {

799 if (!chctx->sumLenArr[i])

800 continue;

801 if (chctx->bandFlagsBuf[i] || chctx->bandWidthT[i]) {

802 for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

803 cw_len = chctx->CWlengthT[j];

804 cw = 0;

805

806 if (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j])) {

807 if (get_bits_count(&q->gb) + cw_len > 512) {

808 av_log(avctx, AV_LOG_WARNING,

809 "Potential problem on band %i, coefficient %i"

810 ": cw_len=%i\n", i, j, cw_len);

811 } else

812 cw = get_bits(&q->gb, cw_len);

813 }

814

815 chctx->codewords[j] = cw;

816 }

817 }

818 }

819 }

820

821 static void imc_refine_bit_allocation(IMCContext *q, IMCChannel *chctx)

822 {

823 int i, j;

824 int bits, summer;

825

826 for (i = 0; i < BANDS; i++) {

827 chctx->sumLenArr[i] = 0;

828 chctx->skipFlagRaw[i] = 0;

829 for (j = band_tab[i]; j < band_tab[i + 1]; j++)

830 chctx->sumLenArr[i] += chctx->CWlengthT[j];

831 if (chctx->bandFlagsBuf[i])

832 if ((((band_tab[i + 1] - band_tab[i]) * 1.5) > chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))

833 chctx->skipFlagRaw[i] = 1;

834 }

835

836 imc_get_skip_coeff(q, chctx);

837

838 for (i = 0; i < BANDS; i++) {

839 chctx->flcoeffs6[i] = chctx->flcoeffs1[i];

840 /* band has flag set and at least one coded coefficient */

841 if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) != chctx->skipFlagCount[i]) {

842 chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]] /

843 q->sqrt_tab[(band_tab[i + 1] - band_tab[i] - chctx->skipFlagCount[i])];

844 }

845 }

846

847 /* calculate bits left, bits needed and adjust bit allocation */

848 bits = summer = 0;

849

850 for (i = 0; i < BANDS; i++) {

851 if (chctx->bandFlagsBuf[i]) {

852 for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

853 if (chctx->skipFlags[j]) {

854 summer += chctx->CWlengthT[j];

855 chctx->CWlengthT[j] = 0;

856 }

857 }

858 bits += chctx->skipFlagBits[i];

859 summer -= chctx->skipFlagBits[i];

860 }

861 }

862 imc_adjust_bit_allocation(q, chctx, summer);

863 }

864

865 static int imc_decode_block(AVCodecContext *avctx, IMCContext *q, int ch)

866 {

867 int stream_format_code;

868 int imc_hdr, i, j, ret;

869 int flag;

870 int bits;

871 int counter, bitscount;

872 IMCChannel *chctx = q->chctx + ch;

873

874

875 /* Check the frame header */

876 imc_hdr = get_bits(&q->gb, 9);

877 if (imc_hdr & 0x18) {

878 av_log(avctx, AV_LOG_ERROR, "frame header check failed!\n");

879 av_log(avctx, AV_LOG_ERROR, "got %X.\n", imc_hdr);

880 return AVERROR_INVALIDDATA;

881 }

882 stream_format_code = get_bits(&q->gb, 3);

883

884 if (stream_format_code & 0x04)

885 chctx->decoder_reset = 1;

886

887 if (chctx->decoder_reset) {

888 for (i = 0; i < BANDS; i++)

889 chctx->old_floor[i] = 1.0;

890 for (i = 0; i < COEFFS; i++)

891 chctx->CWdecoded[i] = 0;

892 chctx->decoder_reset = 0;

893 }

894

895 flag = get_bits1(&q->gb);

896 if (stream_format_code & 0x1)

897 imc_read_level_coeffs_raw(q, stream_format_code, chctx->levlCoeffBuf);

898 else

899 imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);

900

901 if (stream_format_code & 0x1)

902 imc_decode_level_coefficients_raw(q, chctx->levlCoeffBuf,

903 chctx->flcoeffs1, chctx->flcoeffs2);

904 else if (stream_format_code & 0x4)

905 imc_decode_level_coefficients(q, chctx->levlCoeffBuf,

906 chctx->flcoeffs1, chctx->flcoeffs2);

907 else

908 imc_decode_level_coefficients2(q, chctx->levlCoeffBuf, chctx->old_floor,

909 chctx->flcoeffs1, chctx->flcoeffs2);

910

911 for(i=0; i<BANDS; i++) {

912 if(chctx->flcoeffs1[i] > INT_MAX) {

913 av_log(avctx, AV_LOG_ERROR, "scalefactor out of range\n");

914 return AVERROR_INVALIDDATA;

915 }

916 }

917

918 memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));

919

920 counter = 0;

921 if (stream_format_code & 0x1) {

922 for (i = 0; i < BANDS; i++) {

923 chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];

924 chctx->bandFlagsBuf[i] = 0;

925 chctx->flcoeffs3[i] = chctx->flcoeffs2[i] * 2;

926 chctx->flcoeffs5[i] = 1.0;

927 }

928 } else {

929 for (i = 0; i < BANDS; i++) {

930 if (chctx->levlCoeffBuf[i] == 16) {

931 chctx->bandWidthT[i] = 0;

932 counter++;

933 } else

934 chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];

935 }

936

937 memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));

938 for (i = 0; i < BANDS - 1; i++)

939 if (chctx->bandWidthT[i])

940 chctx->bandFlagsBuf[i] = get_bits1(&q->gb);

941

942 imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2,

943 chctx->bandWidthT, chctx->flcoeffs3,

944 chctx->flcoeffs5);

945 }

946

947 bitscount = 0;

948 /* first 4 bands will be assigned 5 bits per coefficient */

949 if (stream_format_code & 0x2) {

950 bitscount += 15;

951

952 chctx->bitsBandT[0] = 5;

953 chctx->CWlengthT[0] = 5;

954 chctx->CWlengthT[1] = 5;

955 chctx->CWlengthT[2] = 5;

956 for (i = 1; i < 4; i++) {

957 if (stream_format_code & 0x1)

958 bits = 5;

959 else

960 bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;

961 chctx->bitsBandT[i] = bits;

962 for (j = band_tab[i]; j < band_tab[i + 1]; j++) {

963 chctx->CWlengthT[j] = bits;

964 bitscount += bits;

965 }

966 }

967 }

968 if (avctx->codec_id == AV_CODEC_ID_IAC) {

969 bitscount += !!chctx->bandWidthT[BANDS - 1];

970 if (!(stream_format_code & 0x2))

971 bitscount += 16;

972 }

973

974 if ((ret = bit_allocation(q, chctx, stream_format_code,

975 512 - bitscount - get_bits_count(&q->gb),

976 flag)) < 0) {

977 av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");

978 chctx->decoder_reset = 1;

979 return ret;

980 }

981

982 if (stream_format_code & 0x1) {

983 for (i = 0; i < BANDS; i++)

984 chctx->skipFlags[i] = 0;

985 } else {

986 imc_refine_bit_allocation(q, chctx);

987 }

988

989 for (i = 0; i < BANDS; i++) {

990 chctx->sumLenArr[i] = 0;

991

992 for (j = band_tab[i]; j < band_tab[i + 1]; j++)

993 if (!chctx->skipFlags[j])

994 chctx->sumLenArr[i] += chctx->CWlengthT[j];

995 }

996

997 memset(chctx->codewords, 0, sizeof(chctx->codewords));

998

999 imc_get_coeffs(avctx, q, chctx);

1000

1001 if (inverse_quant_coeff(q, chctx, stream_format_code) < 0) {

1002 av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");

1003 chctx->decoder_reset = 1;

1004 return AVERROR_INVALIDDATA;

1005 }

1006

1007 memset(chctx->skipFlags, 0, sizeof(chctx->skipFlags));

1008

1009 imc_imdct256(q, chctx, avctx->channels);

1010

1011 return 0;

1012 }

1013

1014 static int imc_decode_frame(AVCodecContext *avctx, void *data,

1015 int *got_frame_ptr, AVPacket *avpkt)

1016 {

1017 AVFrame *frame = data;

1018 const uint8_t *buf = avpkt->data;

1019 int buf_size = avpkt->size;

1020 int ret, i;

1021

1022 IMCContext *q = avctx->priv_data;

1023

1024 LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2 + FF_INPUT_BUFFER_PADDING_SIZE/2]);

1025

1026 if (buf_size < IMC_BLOCK_SIZE * avctx->channels) {

1027 av_log(avctx, AV_LOG_ERROR, "frame too small!\n");

1028 return AVERROR_INVALIDDATA;

1029 }

1030

1031 /* get output buffer */

1032 frame->nb_samples = COEFFS;

1033 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

1034 return ret;

1035

1036 for (i = 0; i < avctx->channels; i++) {

1037 q->out_samples = (float *)frame->extended_data[i];

1038

1039 q->bdsp.bswap16_buf(buf16, (const uint16_t *) buf, IMC_BLOCK_SIZE / 2);

1040

1041 init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);

1042

1043 buf += IMC_BLOCK_SIZE;

1044

1045 if ((ret = imc_decode_block(avctx, q, i)) < 0)

1046 return ret;

1047 }

1048

1049 if (avctx->channels == 2) {

1050 q->fdsp->butterflies_float((float *)frame->extended_data[0],

1051 (float *)frame->extended_data[1], COEFFS);

1052 }

1053

1054 *got_frame_ptr = 1;

1055

1056 return IMC_BLOCK_SIZE * avctx->channels;

1057 }

1058

1059 static av_cold int imc_decode_close(AVCodecContext * avctx)

1060 {

1061 IMCContext *q = avctx->priv_data;

1062

1063 ff_fft_end(&q->fft);

1064 av_freep(&q->fdsp);

1065

1066 return 0;

1067 }

1068

1069 static av_cold void flush(AVCodecContext *avctx)

1070 {

1071 IMCContext *q = avctx->priv_data;

1072

1073 q->chctx[0].decoder_reset =

1074 q->chctx[1].decoder_reset = 1;

1075 }

1076

1077 #if CONFIG_IMC_DECODER

1078 AVCodec ff_imc_decoder = {

1079 .name = "imc",

1080 .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),

1081 .type = AVMEDIA_TYPE_AUDIO,

1082 .id = AV_CODEC_ID_IMC,

1083 .priv_data_size = sizeof(IMCContext),

1084 .init = imc_decode_init,

1085 .close = imc_decode_close,

1086 .decode = imc_decode_frame,

1087 .flush = flush,

1088 .capabilities = CODEC_CAP_DR1,

1089 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,

1090 AV_SAMPLE_FMT_NONE },

1091 };

1092 #endif

1093 #if CONFIG_IAC_DECODER

1094 AVCodec ff_iac_decoder = {

1095 .name = "iac",

1096 .long_name = NULL_IF_CONFIG_SMALL("IAC (Indeo Audio Coder)"),

1097 .type = AVMEDIA_TYPE_AUDIO,

1098 .id = AV_CODEC_ID_IAC,

1099 .priv_data_size = sizeof(IMCContext),

1100 .init = imc_decode_init,

1101 .close = imc_decode_close,

1102 .decode = imc_decode_frame,

1103 .flush = flush,

1104 .capabilities = CODEC_CAP_DR1,

1105 .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,

1106 AV_SAMPLE_FMT_NONE },

1107 };

1108 #endif

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