FFmpeg: libavcodec/mss3.c Source File

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libavcodec

mss3.c

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1 /*

2 * Microsoft Screen 3 (aka Microsoft ATC Screen) 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 * Microsoft Screen 3 (aka Microsoft ATC Screen) decoder

25 */

27 #include "avcodec.h"

28 #include "bytestream.h"

29 #include "dsputil.h"

30 #include "internal.h"

31 #include "mss34dsp.h"

33 #define HEADER_SIZE 27

35 #define MODEL2_SCALE 13

36 #define MODEL_SCALE 15

37 #define MODEL256_SEC_SCALE 9

39 typedef struct Model2 {

40 int upd_val, till_rescale;

41 unsigned zero_freq, zero_weight;

42 unsigned total_freq, total_weight;

43 } Model2;

45 typedef struct Model {

46 int weights[16], freqs[16];

47 int num_syms;

48 int tot_weight;

49 int upd_val, max_upd_val, till_rescale;

50 } Model;

52 typedef struct Model256 {

53 int weights[256], freqs[256];

54 int tot_weight;

55 int secondary[68];

56 int sec_size;

57 int upd_val, max_upd_val, till_rescale;

58 } Model256;

60 #define RAC_BOTTOM 0x01000000

61 typedef struct RangeCoder {

62 const uint8_t *src, *src_end;

64 uint32_t range, low;

65 int got_error;

66 } RangeCoder;

68 enum BlockType {

69 FILL_BLOCK = 0,

70 IMAGE_BLOCK,

71 DCT_BLOCK,

72 HAAR_BLOCK,

73 SKIP_BLOCK

74 };

76 typedef struct BlockTypeContext {

77 int last_type;

78 Model bt_model[5];

79 } BlockTypeContext;

81 typedef struct FillBlockCoder {

82 int fill_val;

83 Model coef_model;

84 } FillBlockCoder;

86 typedef struct ImageBlockCoder {

87 Model256 esc_model, vec_entry_model;

88 Model vec_size_model;

89 Model vq_model[125];

90 } ImageBlockCoder;

92 typedef struct DCTBlockCoder {

93 int *prev_dc;

94 int prev_dc_stride;

95 int prev_dc_height;

96 int quality;

97 uint16_t qmat[64];

98 Model dc_model;

99 Model2 sign_model;

100 Model256 ac_model;

101 } DCTBlockCoder;

102

103 typedef struct HaarBlockCoder {

104 int quality, scale;

105 Model256 coef_model;

106 Model coef_hi_model;

107 } HaarBlockCoder;

108

109 typedef struct MSS3Context {

110 AVCodecContext *avctx;

111 AVFrame pic;

112

113 int got_error;

114 RangeCoder coder;

115 BlockTypeContext btype[3];

116 FillBlockCoder fill_coder[3];

117 ImageBlockCoder image_coder[3];

118 DCTBlockCoder dct_coder[3];

119 HaarBlockCoder haar_coder[3];

120

121 int dctblock[64];

122 int hblock[16 * 16];

123 } MSS3Context;

124

125

126 static void model2_reset(Model2 *m)

127 {

128 m->zero_weight = 1;

129 m->total_weight = 2;

130 m->zero_freq = 0x1000;

131 m->total_freq = 0x2000;

132 m->upd_val = 4;

133 m->till_rescale = 4;

134 }

135

136 static void model2_update(Model2 *m, int bit)

137 {

138 unsigned scale;

139

140 if (!bit)

141 m->zero_weight++;

142 m->till_rescale--;

143 if (m->till_rescale)

144 return;

145

146 m->total_weight += m->upd_val;

147 if (m->total_weight > 0x2000) {

148 m->total_weight = (m->total_weight + 1) >> 1;

149 m->zero_weight = (m->zero_weight + 1) >> 1;

150 if (m->total_weight == m->zero_weight)

151 m->total_weight = m->zero_weight + 1;

152 }

153 m->upd_val = m->upd_val * 5 >> 2;

154 if (m->upd_val > 64)

155 m->upd_val = 64;

156 scale = 0x80000000u / m->total_weight;

157 m->zero_freq = m->zero_weight * scale >> 18;

158 m->total_freq = m->total_weight * scale >> 18;

159 m->till_rescale = m->upd_val;

160 }

161

162 static void model_update(Model *m, int val)

163 {

164 int i, sum = 0;

165 unsigned scale;

166

167 m->weights[val]++;

168 m->till_rescale--;

169 if (m->till_rescale)

170 return;

171 m->tot_weight += m->upd_val;

172

173 if (m->tot_weight > 0x8000) {

174 m->tot_weight = 0;

175 for (i = 0; i < m->num_syms; i++) {

176 m->weights[i] = (m->weights[i] + 1) >> 1;

177 m->tot_weight += m->weights[i];

178 }

179 }

180 scale = 0x80000000u / m->tot_weight;

181 for (i = 0; i < m->num_syms; i++) {

182 m->freqs[i] = sum * scale >> 16;

183 sum += m->weights[i];

184 }

185

186 m->upd_val = m->upd_val * 5 >> 2;

187 if (m->upd_val > m->max_upd_val)

188 m->upd_val = m->max_upd_val;

189 m->till_rescale = m->upd_val;

190 }

191

192 static void model_reset(Model *m)

193 {

194 int i;

195

196 m->tot_weight = 0;

197 for (i = 0; i < m->num_syms - 1; i++)

198 m->weights[i] = 1;

199 m->weights[m->num_syms - 1] = 0;

200

201 m->upd_val = m->num_syms;

202 m->till_rescale = 1;

203 model_update(m, m->num_syms - 1);

204 m->till_rescale =

205 m->upd_val = (m->num_syms + 6) >> 1;

206 }

207

208 static av_cold void model_init(Model *m, int num_syms)

209 {

210 m->num_syms = num_syms;

211 m->max_upd_val = 8 * num_syms + 48;

212

213 model_reset(m);

214 }

215

216 static void model256_update(Model256 *m, int val)

217 {

218 int i, sum = 0;

219 unsigned scale;

220 int send, sidx = 1;

221

222 m->weights[val]++;

223 m->till_rescale--;

224 if (m->till_rescale)

225 return;

226 m->tot_weight += m->upd_val;

227

228 if (m->tot_weight > 0x8000) {

229 m->tot_weight = 0;

230 for (i = 0; i < 256; i++) {

231 m->weights[i] = (m->weights[i] + 1) >> 1;

232 m->tot_weight += m->weights[i];

233 }

234 }

235 scale = 0x80000000u / m->tot_weight;

236 m->secondary[0] = 0;

237 for (i = 0; i < 256; i++) {

238 m->freqs[i] = sum * scale >> 16;

239 sum += m->weights[i];

240 send = m->freqs[i] >> MODEL256_SEC_SCALE;

241 while (sidx <= send)

242 m->secondary[sidx++] = i - 1;

243 }

244 while (sidx < m->sec_size)

245 m->secondary[sidx++] = 255;

246

247 m->upd_val = m->upd_val * 5 >> 2;

248 if (m->upd_val > m->max_upd_val)

249 m->upd_val = m->max_upd_val;

250 m->till_rescale = m->upd_val;

251 }

252

253 static void model256_reset(Model256 *m)

254 {

255 int i;

256

257 for (i = 0; i < 255; i++)

258 m->weights[i] = 1;

259 m->weights[255] = 0;

260

261 m->tot_weight = 0;

262 m->upd_val = 256;

263 m->till_rescale = 1;

264 model256_update(m, 255);

265 m->till_rescale =

266 m->upd_val = (256 + 6) >> 1;

267 }

268

269 static av_cold void model256_init(Model256 *m)

270 {

271 m->max_upd_val = 8 * 256 + 48;

272 m->sec_size = (1 << 6) + 2;

273

274 model256_reset(m);

275 }

276

277 static void rac_init(RangeCoder *c, const uint8_t *src, int size)

278 {

279 int i;

280

281 c->src = src;

282 c->src_end = src + size;

283 c->low = 0;

284 for (i = 0; i < FFMIN(size, 4); i++)

285 c->low = (c->low << 8) | *c->src++;

286 c->range = 0xFFFFFFFF;

287 c->got_error = 0;

288 }

289

290 static void rac_normalise(RangeCoder *c)

291 {

292 for (;;) {

293 c->range <<= 8;

294 c->low <<= 8;

295 if (c->src < c->src_end) {

296 c->low |= *c->src++;

297 } else if (!c->low) {

298 c->got_error = 1;

299 c->low = 1;

300 }

301 if (c->range >= RAC_BOTTOM)

302 return;

303 }

304 }

305

306 static int rac_get_bit(RangeCoder *c)

307 {

308 int bit;

309

310 c->range >>= 1;

311

312 bit = (c->range <= c->low);

313 if (bit)

314 c->low -= c->range;

315

316 if (c->range < RAC_BOTTOM)

317 rac_normalise(c);

318

319 return bit;

320 }

321

322 static int rac_get_bits(RangeCoder *c, int nbits)

323 {

324 int val;

325

326 c->range >>= nbits;

327 val = c->low / c->range;

328 c->low -= c->range * val;

329

330 if (c->range < RAC_BOTTOM)

331 rac_normalise(c);

332

333 return val;

334 }

335

336 static int rac_get_model2_sym(RangeCoder *c, Model2 *m)

337 {

338 int bit, helper;

339

340 helper = m->zero_freq * (c->range >> MODEL2_SCALE);

341 bit = (c->low >= helper);

342 if (bit) {

343 c->low -= helper;

344 c->range -= helper;

345 } else {

346 c->range = helper;

347 }

348

349 if (c->range < RAC_BOTTOM)

350 rac_normalise(c);

351

352 model2_update(m, bit);

353

354 return bit;

355 }

356

357 static int rac_get_model_sym(RangeCoder *c, Model *m)

358 {

359 int prob, prob2, helper, val;

360 int end, end2;

361

362 prob = 0;

363 prob2 = c->range;

364 c->range >>= MODEL_SCALE;

365 val = 0;

366 end = m->num_syms >> 1;

367 end2 = m->num_syms;

368 do {

369 helper = m->freqs[end] * c->range;

370 if (helper <= c->low) {

371 val = end;

372 prob = helper;

373 } else {

374 end2 = end;

375 prob2 = helper;

376 }

377 end = (end2 + val) >> 1;

378 } while (end != val);

379 c->low -= prob;

380 c->range = prob2 - prob;

381 if (c->range < RAC_BOTTOM)

382 rac_normalise(c);

383

384 model_update(m, val);

385

386 return val;

387 }

388

389 static int rac_get_model256_sym(RangeCoder *c, Model256 *m)

390 {

391 int prob, prob2, helper, val;

392 int start, end;

393 int ssym;

394

395 prob2 = c->range;

396 c->range >>= MODEL_SCALE;

397

398 helper = c->low / c->range;

399 ssym = helper >> MODEL256_SEC_SCALE;

400 val = m->secondary[ssym];

401

402 end = start = m->secondary[ssym + 1] + 1;

403 while (end > val + 1) {

404 ssym = (end + val) >> 1;

405 if (m->freqs[ssym] <= helper) {

406 end = start;

407 val = ssym;

408 } else {

409 end = (end + val) >> 1;

410 start = ssym;

411 }

412 }

413 prob = m->freqs[val] * c->range;

414 if (val != 255)

415 prob2 = m->freqs[val + 1] * c->range;

416

417 c->low -= prob;

418 c->range = prob2 - prob;

419 if (c->range < RAC_BOTTOM)

420 rac_normalise(c);

421

422 model256_update(m, val);

423

424 return val;

425 }

426

427 static int decode_block_type(RangeCoder *c, BlockTypeContext *bt)

428 {

429 bt->last_type = rac_get_model_sym(c, &bt->bt_model[bt->last_type]);

430

431 return bt->last_type;

432 }

433

434 static int decode_coeff(RangeCoder *c, Model *m)

435 {

436 int val, sign;

437

438 val = rac_get_model_sym(c, m);

439 if (val) {

440 sign = rac_get_bit(c);

441 if (val > 1) {

442 val--;

443 val = (1 << val) + rac_get_bits(c, val);

444 }

445 if (!sign)

446 val = -val;

447 }

448

449 return val;

450 }

451

452 static void decode_fill_block(RangeCoder *c, FillBlockCoder *fc,

453 uint8_t *dst, int stride, int block_size)

454 {

455 int i;

456

457 fc->fill_val += decode_coeff(c, &fc->coef_model);

458

459 for (i = 0; i < block_size; i++, dst += stride)

460 memset(dst, fc->fill_val, block_size);

461 }

462

463 static void decode_image_block(RangeCoder *c, ImageBlockCoder *ic,

464 uint8_t *dst, int stride, int block_size)

465 {

466 int i, j;

467 int vec_size;

468 int vec[4];

469 int prev_line[16];

470 int A, B, C;

471

472 vec_size = rac_get_model_sym(c, &ic->vec_size_model) + 2;

473 for (i = 0; i < vec_size; i++)

474 vec[i] = rac_get_model256_sym(c, &ic->vec_entry_model);

475 for (; i < 4; i++)

476 vec[i] = 0;

477 memset(prev_line, 0, sizeof(prev_line));

478

479 for (j = 0; j < block_size; j++) {

480 A = 0;

481 B = 0;

482 for (i = 0; i < block_size; i++) {

483 C = B;

484 B = prev_line[i];

485 A = rac_get_model_sym(c, &ic->vq_model[A + B * 5 + C * 25]);

486

487 prev_line[i] = A;

488 if (A < 4)

489 dst[i] = vec[A];

490 else

491 dst[i] = rac_get_model256_sym(c, &ic->esc_model);

492 }

493 dst += stride;

494 }

495 }

496

497 static int decode_dct(RangeCoder *c, DCTBlockCoder *bc, int *block,

498 int bx, int by)

499 {

500 int skip, val, sign, pos = 1, zz_pos, dc;

501 int blk_pos = bx + by * bc->prev_dc_stride;

502

503 memset(block, 0, sizeof(*block) * 64);

504

505 dc = decode_coeff(c, &bc->dc_model);

506 if (by) {

507 if (bx) {

508 int l, tl, t;

509

510 l = bc->prev_dc[blk_pos - 1];

511 tl = bc->prev_dc[blk_pos - 1 - bc->prev_dc_stride];

512 t = bc->prev_dc[blk_pos - bc->prev_dc_stride];

513

514 if (FFABS(t - tl) <= FFABS(l - tl))

515 dc += l;

516 else

517 dc += t;

518 } else {

519 dc += bc->prev_dc[blk_pos - bc->prev_dc_stride];

520 }

521 } else if (bx) {

522 dc += bc->prev_dc[bx - 1];

523 }

524 bc->prev_dc[blk_pos] = dc;

525 block[0] = dc * bc->qmat[0];

526

527 while (pos < 64) {

528 val = rac_get_model256_sym(c, &bc->ac_model);

529 if (!val)

530 return 0;

531 if (val == 0xF0) {

532 pos += 16;

533 continue;

534 }

535 skip = val >> 4;

536 val = val & 0xF;

537 if (!val)

538 return -1;

539 pos += skip;

540 if (pos >= 64)

541 return -1;

542

543 sign = rac_get_model2_sym(c, &bc->sign_model);

544 if (val > 1) {

545 val--;

546 val = (1 << val) + rac_get_bits(c, val);

547 }

548 if (!sign)

549 val = -val;

550

551 zz_pos = ff_zigzag_direct[pos];

552 block[zz_pos] = val * bc->qmat[zz_pos];

553 pos++;

554 }

555

556 return pos == 64 ? 0 : -1;

557 }

558

559 static void decode_dct_block(RangeCoder *c, DCTBlockCoder *bc,

560 uint8_t *dst, int stride, int block_size,

561 int *block, int mb_x, int mb_y)

562 {

563 int i, j;

564 int bx, by;

565 int nblocks = block_size >> 3;

566

567 bx = mb_x * nblocks;

568 by = mb_y * nblocks;

569

570 for (j = 0; j < nblocks; j++) {

571 for (i = 0; i < nblocks; i++) {

572 if (decode_dct(c, bc, block, bx + i, by + j)) {

573 c->got_error = 1;

574 return;

575 }

576 ff_mss34_dct_put(dst + i * 8, stride, block);

577 }

578 dst += 8 * stride;

579 }

580 }

581

582 static void decode_haar_block(RangeCoder *c, HaarBlockCoder *hc,

583 uint8_t *dst, int stride, int block_size,

584 int *block)

585 {

586 const int hsize = block_size >> 1;

587 int A, B, C, D, t1, t2, t3, t4;

588 int i, j;

589

590 for (j = 0; j < block_size; j++) {

591 for (i = 0; i < block_size; i++) {

592 if (i < hsize && j < hsize)

593 block[i] = rac_get_model256_sym(c, &hc->coef_model);

594 else

595 block[i] = decode_coeff(c, &hc->coef_hi_model);

596 block[i] *= hc->scale;

597 }

598 block += block_size;

599 }

600 block -= block_size * block_size;

601

602 for (j = 0; j < hsize; j++) {

603 for (i = 0; i < hsize; i++) {

604 A = block[i];

605 B = block[i + hsize];

606 C = block[i + hsize * block_size];

607 D = block[i + hsize * block_size + hsize];

608

609 t1 = A - B;

610 t2 = C - D;

611 t3 = A + B;

612 t4 = C + D;

613 dst[i * 2] = av_clip_uint8(t1 - t2);

614 dst[i * 2 + stride] = av_clip_uint8(t1 + t2);

615 dst[i * 2 + 1] = av_clip_uint8(t3 - t4);

616 dst[i * 2 + 1 + stride] = av_clip_uint8(t3 + t4);

617 }

618 block += block_size;

619 dst += stride * 2;

620 }

621 }

622

623 static void reset_coders(MSS3Context *ctx, int quality)

624 {

625 int i, j;

626

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

628 ctx->btype[i].last_type = SKIP_BLOCK;

629 for (j = 0; j < 5; j++)

630 model_reset(&ctx->btype[i].bt_model[j]);

631 ctx->fill_coder[i].fill_val = 0;

632 model_reset(&ctx->fill_coder[i].coef_model);

633 model256_reset(&ctx->image_coder[i].esc_model);

634 model256_reset(&ctx->image_coder[i].vec_entry_model);

635 model_reset(&ctx->image_coder[i].vec_size_model);

636 for (j = 0; j < 125; j++)

637 model_reset(&ctx->image_coder[i].vq_model[j]);

638 if (ctx->dct_coder[i].quality != quality) {

639 ctx->dct_coder[i].quality = quality;

640 ff_mss34_gen_quant_mat(ctx->dct_coder[i].qmat, quality, !i);

641 }

642 memset(ctx->dct_coder[i].prev_dc, 0,

643 sizeof(*ctx->dct_coder[i].prev_dc) *

644 ctx->dct_coder[i].prev_dc_stride *

645 ctx->dct_coder[i].prev_dc_height);

646 model_reset(&ctx->dct_coder[i].dc_model);

647 model2_reset(&ctx->dct_coder[i].sign_model);

648 model256_reset(&ctx->dct_coder[i].ac_model);

649 if (ctx->haar_coder[i].quality != quality) {

650 ctx->haar_coder[i].quality = quality;

651 ctx->haar_coder[i].scale = 17 - 7 * quality / 50;

652 }

653 model_reset(&ctx->haar_coder[i].coef_hi_model);

654 model256_reset(&ctx->haar_coder[i].coef_model);

655 }

656 }

657

658 static av_cold void init_coders(MSS3Context *ctx)

659 {

660 int i, j;

661

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

663 for (j = 0; j < 5; j++)

664 model_init(&ctx->btype[i].bt_model[j], 5);

665 model_init(&ctx->fill_coder[i].coef_model, 12);

666 model256_init(&ctx->image_coder[i].esc_model);

667 model256_init(&ctx->image_coder[i].vec_entry_model);

668 model_init(&ctx->image_coder[i].vec_size_model, 3);

669 for (j = 0; j < 125; j++)

670 model_init(&ctx->image_coder[i].vq_model[j], 5);

671 model_init(&ctx->dct_coder[i].dc_model, 12);

672 model256_init(&ctx->dct_coder[i].ac_model);

673 model_init(&ctx->haar_coder[i].coef_hi_model, 12);

674 model256_init(&ctx->haar_coder[i].coef_model);

675 }

676 }

677

678 static int mss3_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,

679 AVPacket *avpkt)

680 {

681 const uint8_t *buf = avpkt->data;

682 int buf_size = avpkt->size;

683 MSS3Context *c = avctx->priv_data;

684 RangeCoder *acoder = &c->coder;

685 GetByteContext gb;

686 uint8_t *dst[3];

687 int dec_width, dec_height, dec_x, dec_y, quality, keyframe;

688 int x, y, i, mb_width, mb_height, blk_size, btype;

689 int ret;

690

691 if (buf_size < HEADER_SIZE) {

692 av_log(avctx, AV_LOG_ERROR,

693 "Frame should have at least %d bytes, got %d instead\n",

694 HEADER_SIZE, buf_size);

695 return AVERROR_INVALIDDATA;

696 }

697

698 bytestream2_init(&gb, buf, buf_size);

699 keyframe = bytestream2_get_be32(&gb);

700 if (keyframe & ~0x301) {

701 av_log(avctx, AV_LOG_ERROR, "Invalid frame type %X\n", keyframe);

702 return AVERROR_INVALIDDATA;

703 }

704 keyframe = !(keyframe & 1);

705 bytestream2_skip(&gb, 6);

706 dec_x = bytestream2_get_be16(&gb);

707 dec_y = bytestream2_get_be16(&gb);

708 dec_width = bytestream2_get_be16(&gb);

709 dec_height = bytestream2_get_be16(&gb);

710

711 if (dec_x + dec_width > avctx->width ||

712 dec_y + dec_height > avctx->height ||

713 (dec_width | dec_height) & 0xF) {

714 av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d +%d,%d\n",

715 dec_width, dec_height, dec_x, dec_y);

716 return AVERROR_INVALIDDATA;

717 }

718 bytestream2_skip(&gb, 4);

719 quality = bytestream2_get_byte(&gb);

720 if (quality < 1 || quality > 100) {

721 av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);

722 return AVERROR_INVALIDDATA;

723 }

724 bytestream2_skip(&gb, 4);

725

726 if (keyframe && !bytestream2_get_bytes_left(&gb)) {

727 av_log(avctx, AV_LOG_ERROR, "Keyframe without data found\n");

728 return AVERROR_INVALIDDATA;

729 }

730 if (!keyframe && c->got_error)

731 return buf_size;

732 c->got_error = 0;

733

734 if ((ret = ff_reget_buffer(avctx, &c->pic)) < 0)

735 return ret;

736 c->pic.key_frame = keyframe;

737 c->pic.pict_type = keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;

738 if (!bytestream2_get_bytes_left(&gb)) {

739 if ((ret = av_frame_ref(data, &c->pic)) < 0)

740 return ret;

741 *got_frame = 1;

742

743 return buf_size;

744 }

745

746 reset_coders(c, quality);

747

748 rac_init(acoder, buf + HEADER_SIZE, buf_size - HEADER_SIZE);

749

750 mb_width = dec_width >> 4;

751 mb_height = dec_height >> 4;

752 dst[0] = c->pic.data[0] + dec_x + dec_y * c->pic.linesize[0];

753 dst[1] = c->pic.data[1] + dec_x / 2 + (dec_y / 2) * c->pic.linesize[1];

754 dst[2] = c->pic.data[2] + dec_x / 2 + (dec_y / 2) * c->pic.linesize[2];

755 for (y = 0; y < mb_height; y++) {

756 for (x = 0; x < mb_width; x++) {

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

758 blk_size = 8 << !i;

759

760 btype = decode_block_type(acoder, c->btype + i);

761 switch (btype) {

762 case FILL_BLOCK:

763 decode_fill_block(acoder, c->fill_coder + i,

764 dst[i] + x * blk_size,

765 c->pic.linesize[i], blk_size);

766 break;

767 case IMAGE_BLOCK:

768 decode_image_block(acoder, c->image_coder + i,

769 dst[i] + x * blk_size,

770 c->pic.linesize[i], blk_size);

771 break;

772 case DCT_BLOCK:

773 decode_dct_block(acoder, c->dct_coder + i,

774 dst[i] + x * blk_size,

775 c->pic.linesize[i], blk_size,

776 c->dctblock, x, y);

777 break;

778 case HAAR_BLOCK:

779 decode_haar_block(acoder, c->haar_coder + i,

780 dst[i] + x * blk_size,

781 c->pic.linesize[i], blk_size,

782 c->hblock);

783 break;

784 }

785 if (c->got_error || acoder->got_error) {

786 av_log(avctx, AV_LOG_ERROR, "Error decoding block %d,%d\n",

787 x, y);

788 c->got_error = 1;

789 return AVERROR_INVALIDDATA;

790 }

791 }

792 }

793 dst[0] += c->pic.linesize[0] * 16;

794 dst[1] += c->pic.linesize[1] * 8;

795 dst[2] += c->pic.linesize[2] * 8;

796 }

797

798 if ((ret = av_frame_ref(data, &c->pic)) < 0)

799 return ret;

800

801 *got_frame = 1;

802

803 return buf_size;

804 }

805

806 static av_cold int mss3_decode_init(AVCodecContext *avctx)

807 {

808 MSS3Context * const c = avctx->priv_data;

809 int i;

810

811 c->avctx = avctx;

812

813 if ((avctx->width & 0xF) || (avctx->height & 0xF)) {

814 av_log(avctx, AV_LOG_ERROR,

815 "Image dimensions should be a multiple of 16.\n");

816 return AVERROR_INVALIDDATA;

817 }

818

819 c->got_error = 0;

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

821 int b_width = avctx->width >> (2 + !!i);

822 int b_height = avctx->height >> (2 + !!i);

823 c->dct_coder[i].prev_dc_stride = b_width;

824 c->dct_coder[i].prev_dc_height = b_height;

825 c->dct_coder[i].prev_dc = av_malloc(sizeof(*c->dct_coder[i].prev_dc) *

826 b_width * b_height);

827 if (!c->dct_coder[i].prev_dc) {

828 av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");

829 while (i >= 0) {

830 av_freep(&c->dct_coder[i].prev_dc);

831 i--;

832 }

833 return AVERROR(ENOMEM);

834 }

835 }

836

837 avctx->pix_fmt = AV_PIX_FMT_YUV420P;

838

839 init_coders(c);

840

841 return 0;

842 }

843

844 static av_cold int mss3_decode_end(AVCodecContext *avctx)

845 {

846 MSS3Context * const c = avctx->priv_data;

847 int i;

848

849 av_frame_unref(&c->pic);

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

851 av_freep(&c->dct_coder[i].prev_dc);

852

853 return 0;

854 }

855

856 AVCodec ff_msa1_decoder = {

857 .name = "msa1",

858 .type = AVMEDIA_TYPE_VIDEO,

859 .id = AV_CODEC_ID_MSA1,

860 .priv_data_size = sizeof(MSS3Context),

861 .init = mss3_decode_init,

862 .close = mss3_decode_end,

863 .decode = mss3_decode_frame,

864 .capabilities = CODEC_CAP_DR1,

865 .long_name = NULL_IF_CONFIG_SMALL("MS ATC Screen"),

866 };

Generated on Wed Jul 10 2013 23:48:02 for FFmpeg by doxygen 1.8.2