FFmpeg: libavcodec/dvdsubdec.c Source File

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libavcodec

dvdsubdec.c

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1 /*

2 * DVD subtitle decoding

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 */

21 #include "avcodec.h"

22 #include "get_bits.h"

23 #include "dsputil.h"

24 #include "libavutil/colorspace.h"

25 #include "libavutil/opt.h"

26 #include "libavutil/imgutils.h"

28 //#define DEBUG

30 typedef struct DVDSubContext

31 {

32 AVClass *class;

33 uint32_t palette[16];

34 char *palette_str;

35 int has_palette;

36 uint8_t colormap[4];

37 uint8_t alpha[256];

38 } DVDSubContext;

40 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)

41 {

42 uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;

43 uint8_t r, g, b;

44 int i, y, cb, cr;

45 int r_add, g_add, b_add;

47 for (i = num_values; i > 0; i--) {

48 y = *ycbcr++;

49 cr = *ycbcr++;

50 cb = *ycbcr++;

51 YUV_TO_RGB1_CCIR(cb, cr);

52 YUV_TO_RGB2_CCIR(r, g, b, y);

53 *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;

54 }

55 }

57 static int decode_run_2bit(GetBitContext *gb, int *color)

58 {

59 unsigned int v, t;

61 v = 0;

62 for (t = 1; v < t && t <= 0x40; t <<= 2)

63 v = (v << 4) | get_bits(gb, 4);

64 *color = v & 3;

65 if (v < 4) { /* Code for fill rest of line */

66 return INT_MAX;

67 }

68 return v >> 2;

69 }

71 static int decode_run_8bit(GetBitContext *gb, int *color)

72 {

73 int len;

74 int has_run = get_bits1(gb);

75 if (get_bits1(gb))

76 *color = get_bits(gb, 8);

77 else

78 *color = get_bits(gb, 2);

79 if (has_run) {

80 if (get_bits1(gb)) {

81 len = get_bits(gb, 7);

82 if (len == 0)

83 len = INT_MAX;

84 else

85 len += 9;

86 } else

87 len = get_bits(gb, 3) + 2;

88 } else

89 len = 1;

90 return len;

91 }

93 static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,

94 const uint8_t *buf, int start, int buf_size, int is_8bit)

95 {

96 GetBitContext gb;

97 int bit_len;

98 int x, y, len, color;

99 uint8_t *d;

100

101 bit_len = (buf_size - start) * 8;

102 init_get_bits(&gb, buf + start, bit_len);

103

104 x = 0;

105 y = 0;

106 d = bitmap;

107 for(;;) {

108 if (get_bits_count(&gb) > bit_len)

109 return -1;

110 if (is_8bit)

111 len = decode_run_8bit(&gb, &color);

112 else

113 len = decode_run_2bit(&gb, &color);

114 len = FFMIN(len, w - x);

115 memset(d + x, color, len);

116 x += len;

117 if (x >= w) {

118 y++;

119 if (y >= h)

120 break;

121 d += linesize;

122 x = 0;

123 /* byte align */

124 align_get_bits(&gb);

125 }

126 }

127 return 0;

128 }

129

130 static void guess_palette(uint32_t *rgba_palette,

131 DVDSubContext* ctx,

132 uint32_t subtitle_color)

133 {

134 static const uint8_t level_map[4][4] = {

135 // this configuration (full range, lowest to highest) in tests

136 // seemed most common, so assume this

137 {0xff},

138 {0x00, 0xff},

139 {0x00, 0x80, 0xff},

140 {0x00, 0x55, 0xaa, 0xff},

141 };

142 uint8_t color_used[16] = { 0 };

143 int nb_opaque_colors, i, level, j, r, g, b;

144 uint8_t *colormap = ctx->colormap, *alpha = ctx->alpha;

145

146 if(ctx->has_palette) {

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

148 rgba_palette[i] = (ctx->palette[colormap[i]] & 0x00ffffff)

149 | ((alpha[i] * 17) << 24);

150 return;

151 }

152

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

154 rgba_palette[i] = 0;

155

156 nb_opaque_colors = 0;

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

158 if (alpha[i] != 0 && !color_used[colormap[i]]) {

159 color_used[colormap[i]] = 1;

160 nb_opaque_colors++;

161 }

162 }

163

164 if (nb_opaque_colors == 0)

165 return;

166

167 j = 0;

168 memset(color_used, 0, 16);

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

170 if (alpha[i] != 0) {

171 if (!color_used[colormap[i]]) {

172 level = level_map[nb_opaque_colors][j];

173 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;

174 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;

175 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;

176 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);

177 color_used[colormap[i]] = (i + 1);

178 j++;

179 } else {

180 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |

181 ((alpha[i] * 17) << 24);

182 }

183 }

184 }

185 }

186

187 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))

188

189 static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,

190 const uint8_t *buf, int buf_size)

191 {

192 int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;

193 int big_offsets, offset_size, is_8bit = 0;

194 const uint8_t *yuv_palette = 0;

195 uint8_t *colormap = ctx->colormap, *alpha = ctx->alpha;

196 int date;

197 int i;

198 int is_menu = 0;

199

200 if (buf_size < 10)

201 return -1;

202

203 if (AV_RB16(buf) == 0) { /* HD subpicture with 4-byte offsets */

204 big_offsets = 1;

205 offset_size = 4;

206 cmd_pos = 6;

207 } else {

208 big_offsets = 0;

209 offset_size = 2;

210 cmd_pos = 2;

211 }

212

213 cmd_pos = READ_OFFSET(buf + cmd_pos);

214

215 while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) {

216 date = AV_RB16(buf + cmd_pos);

217 next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);

218 av_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",

219 cmd_pos, next_cmd_pos, date);

220 pos = cmd_pos + 2 + offset_size;

221 offset1 = -1;

222 offset2 = -1;

223 x1 = y1 = x2 = y2 = 0;

224 while (pos < buf_size) {

225 cmd = buf[pos++];

226 av_dlog(NULL, "cmd=%02x\n", cmd);

227 switch(cmd) {

228 case 0x00:

229 /* menu subpicture */

230 is_menu = 1;

231 break;

232 case 0x01:

233 /* set start date */

234 sub_header->start_display_time = (date << 10) / 90;

235 break;

236 case 0x02:

237 /* set end date */

238 sub_header->end_display_time = (date << 10) / 90;

239 break;

240 case 0x03:

241 /* set colormap */

242 if ((buf_size - pos) < 2)

243 goto fail;

244 colormap[3] = buf[pos] >> 4;

245 colormap[2] = buf[pos] & 0x0f;

246 colormap[1] = buf[pos + 1] >> 4;

247 colormap[0] = buf[pos + 1] & 0x0f;

248 pos += 2;

249 break;

250 case 0x04:

251 /* set alpha */

252 if ((buf_size - pos) < 2)

253 goto fail;

254 alpha[3] = buf[pos] >> 4;

255 alpha[2] = buf[pos] & 0x0f;

256 alpha[1] = buf[pos + 1] >> 4;

257 alpha[0] = buf[pos + 1] & 0x0f;

258 pos += 2;

259 av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);

260 break;

261 case 0x05:

262 case 0x85:

263 if ((buf_size - pos) < 6)

264 goto fail;

265 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);

266 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];

267 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);

268 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];

269 if (cmd & 0x80)

270 is_8bit = 1;

271 av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);

272 pos += 6;

273 break;

274 case 0x06:

275 if ((buf_size - pos) < 4)

276 goto fail;

277 offset1 = AV_RB16(buf + pos);

278 offset2 = AV_RB16(buf + pos + 2);

279 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);

280 pos += 4;

281 break;

282 case 0x86:

283 if ((buf_size - pos) < 8)

284 goto fail;

285 offset1 = AV_RB32(buf + pos);

286 offset2 = AV_RB32(buf + pos + 4);

287 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);

288 pos += 8;

289 break;

290

291 case 0x83:

292 /* HD set palette */

293 if ((buf_size - pos) < 768)

294 goto fail;

295 yuv_palette = buf + pos;

296 pos += 768;

297 break;

298 case 0x84:

299 /* HD set contrast (alpha) */

300 if ((buf_size - pos) < 256)

301 goto fail;

302 for (i = 0; i < 256; i++)

303 alpha[i] = 0xFF - buf[pos+i];

304 pos += 256;

305 break;

306

307 case 0xff:

308 goto the_end;

309 default:

310 av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);

311 goto the_end;

312 }

313 }

314 the_end:

315 if (offset1 >= 0) {

316 int w, h;

317 uint8_t *bitmap;

318

319 /* decode the bitmap */

320 w = x2 - x1 + 1;

321 if (w < 0)

322 w = 0;

323 h = y2 - y1;

324 if (h < 0)

325 h = 0;

326 if (w > 0 && h > 0) {

327 if (sub_header->rects != NULL) {

328 for (i = 0; i < sub_header->num_rects; i++) {

329 av_freep(&sub_header->rects[i]->pict.data[0]);

330 av_freep(&sub_header->rects[i]->pict.data[1]);

331 av_freep(&sub_header->rects[i]);

332 }

333 av_freep(&sub_header->rects);

334 sub_header->num_rects = 0;

335 }

336

337 bitmap = av_malloc(w * h);

338 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));

339 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));

340 sub_header->num_rects = 1;

341 sub_header->rects[0]->pict.data[0] = bitmap;

342 decode_rle(bitmap, w * 2, w, (h + 1) / 2,

343 buf, offset1, buf_size, is_8bit);

344 decode_rle(bitmap + w, w * 2, w, h / 2,

345 buf, offset2, buf_size, is_8bit);

346 sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);

347 if (is_8bit) {

348 if (yuv_palette == 0)

349 goto fail;

350 sub_header->rects[0]->nb_colors = 256;

351 yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);

352 } else {

353 sub_header->rects[0]->nb_colors = 4;

354 guess_palette((uint32_t*)sub_header->rects[0]->pict.data[1], ctx,

355 0xffff00);

356 }

357 sub_header->rects[0]->x = x1;

358 sub_header->rects[0]->y = y1;

359 sub_header->rects[0]->w = w;

360 sub_header->rects[0]->h = h;

361 sub_header->rects[0]->type = SUBTITLE_BITMAP;

362 sub_header->rects[0]->pict.linesize[0] = w;

363 sub_header->rects[0]->flags = is_menu ? AV_SUBTITLE_FLAG_FORCED : 0;

364 }

365 }

366 if (next_cmd_pos < cmd_pos) {

367 av_log(NULL, AV_LOG_ERROR, "Invalid command offset\n");

368 break;

369 }

370 if (next_cmd_pos == cmd_pos)

371 break;

372 cmd_pos = next_cmd_pos;

373 }

374 if (sub_header->num_rects > 0)

375 return is_menu;

376 fail:

377 if (sub_header->rects != NULL) {

378 for (i = 0; i < sub_header->num_rects; i++) {

379 av_freep(&sub_header->rects[i]->pict.data[0]);

380 av_freep(&sub_header->rects[i]->pict.data[1]);

381 av_freep(&sub_header->rects[i]);

382 }

383 av_freep(&sub_header->rects);

384 sub_header->num_rects = 0;

385 }

386 return -1;

387 }

388

389 static int is_transp(const uint8_t *buf, int pitch, int n,

390 const uint8_t *transp_color)

391 {

392 int i;

393 for(i = 0; i < n; i++) {

394 if (!transp_color[*buf])

395 return 0;

396 buf += pitch;

397 }

398 return 1;

399 }

400

401 /* return 0 if empty rectangle, 1 if non empty */

402 static int find_smallest_bounding_rectangle(AVSubtitle *s)

403 {

404 uint8_t transp_color[256] = { 0 };

405 int y1, y2, x1, x2, y, w, h, i;

406 uint8_t *bitmap;

407

408 if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)

409 return 0;

410

411 for(i = 0; i < s->rects[0]->nb_colors; i++) {

412 if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)

413 transp_color[i] = 1;

414 }

415 y1 = 0;

416 while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],

417 1, s->rects[0]->w, transp_color))

418 y1++;

419 if (y1 == s->rects[0]->h) {

420 av_freep(&s->rects[0]->pict.data[0]);

421 s->rects[0]->w = s->rects[0]->h = 0;

422 return 0;

423 }

424

425 y2 = s->rects[0]->h - 1;

426 while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,

427 s->rects[0]->w, transp_color))

428 y2--;

429 x1 = 0;

430 while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],

431 s->rects[0]->h, transp_color))

432 x1++;

433 x2 = s->rects[0]->w - 1;

434 while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,

435 transp_color))

436 x2--;

437 w = x2 - x1 + 1;

438 h = y2 - y1 + 1;

439 bitmap = av_malloc(w * h);

440 if (!bitmap)

441 return 1;

442 for(y = 0; y < h; y++) {

443 memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);

444 }

445 av_freep(&s->rects[0]->pict.data[0]);

446 s->rects[0]->pict.data[0] = bitmap;

447 s->rects[0]->pict.linesize[0] = w;

448 s->rects[0]->w = w;

449 s->rects[0]->h = h;

450 s->rects[0]->x += x1;

451 s->rects[0]->y += y1;

452 return 1;

453 }

454

455 #ifdef DEBUG

456 #undef fprintf

457 #undef perror

458 #undef exit

459 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,

460 uint32_t *rgba_palette)

461 {

462 int x, y, v;

463 FILE *f;

464

465 f = fopen(filename, "w");

466 if (!f) {

467 perror(filename);

468 exit(1);

469 }

470 fprintf(f, "P6\n"

471 "%d %d\n"

472 "%d\n",

473 w, h, 255);

474 for(y = 0; y < h; y++) {

475 for(x = 0; x < w; x++) {

476 v = rgba_palette[bitmap[y * w + x]];

477 putc((v >> 16) & 0xff, f);

478 putc((v >> 8) & 0xff, f);

479 putc((v >> 0) & 0xff, f);

480 }

481 }

482 fclose(f);

483 }

484 #endif

485

486 static int dvdsub_decode(AVCodecContext *avctx,

487 void *data, int *data_size,

488 AVPacket *avpkt)

489 {

490 DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;

491 const uint8_t *buf = avpkt->data;

492 int buf_size = avpkt->size;

493 AVSubtitle *sub = data;

494 int is_menu;

495

496 is_menu = decode_dvd_subtitles(ctx, sub, buf, buf_size);

497

498 if (is_menu < 0) {

499 no_subtitle:

500 *data_size = 0;

501

502 return buf_size;

503 }

504 if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)

505 goto no_subtitle;

506

507 #if defined(DEBUG)

508 av_dlog(NULL, "start=%d ms end =%d ms\n",

509 sub->start_display_time,

510 sub->end_display_time);

511 ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0],

512 sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]);

513 #endif

514

515 *data_size = 1;

516 return buf_size;

517 }

518

519 static void parse_palette(DVDSubContext *ctx, char *p)

520 {

521 int i;

522

523 ctx->has_palette = 1;

524 for(i=0;i<16;i++) {

525 ctx->palette[i] = strtoul(p, &p, 16);

526 while(*p == ',' || isspace(*p))

527 p++;

528 }

529 }

530

531 static int dvdsub_parse_extradata(AVCodecContext *avctx)

532 {

533 DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;

534 char *dataorig, *data;

535

536 if (!avctx->extradata || !avctx->extradata_size)

537 return 1;

538

539 dataorig = data = av_malloc(avctx->extradata_size+1);

540 if (!data)

541 return AVERROR(ENOMEM);

542 memcpy(data, avctx->extradata, avctx->extradata_size);

543 data[avctx->extradata_size] = '0円';

544

545 for(;;) {

546 int pos = strcspn(data, "\n\r");

547 if (pos==0 && *data==0)

548 break;

549

550 if (strncmp("palette:", data, 8) == 0) {

551 parse_palette(ctx, data + 8);

552 } else if (strncmp("size:", data, 5) == 0) {

553 int w, h;

554 if (sscanf(data + 5, "%dx%d", &w, &h) == 2 &&

555 av_image_check_size(w, h, 0, avctx) >= 0)

556 avcodec_set_dimensions(avctx, w, h);

557 }

558

559 data += pos;

560 data += strspn(data, "\n\r");

561 }

562

563 av_free(dataorig);

564 return 1;

565 }

566

567 static int dvdsub_init(AVCodecContext *avctx)

568 {

569 DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;

570 int ret;

571

572 if ((ret = dvdsub_parse_extradata(avctx)) < 0)

573 return ret;

574

575 if (ctx->palette_str)

576 parse_palette(ctx, ctx->palette_str);

577 if (ctx->has_palette) {

578 int i;

579 av_log(avctx, AV_LOG_DEBUG, "palette:");

580 for(i=0;i<16;i++)

581 av_log(avctx, AV_LOG_DEBUG, " 0x%06x", ctx->palette[i]);

582 av_log(avctx, AV_LOG_DEBUG, "\n");

583 }

584

585 return 1;

586 }

587

588 #define OFFSET(field) offsetof(DVDSubContext, field)

589 #define VD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM

590 static const AVOption options[] = {

591 { "palette", "set the global palette", OFFSET(palette_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, VD },

592 { NULL }

593 };

594 static const AVClass class = {

595 .class_name = "dvdsubdec",

596 .item_name = av_default_item_name,

597 .option = options,

598 .version = LIBAVUTIL_VERSION_INT,

599 };

600

601 AVCodec ff_dvdsub_decoder = {

602 .name = "dvdsub",

603 .type = AVMEDIA_TYPE_SUBTITLE,

604 .id = AV_CODEC_ID_DVD_SUBTITLE,

605 .priv_data_size = sizeof(DVDSubContext),

606 .init = dvdsub_init,

607 .decode = dvdsub_decode,

608 .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),

609 .priv_class = &class,

610 };

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