1/* 2 * DVD subtitle decoding 3 * Copyright (c) 2005 Fabrice Bellard 4 * 5 * This file is part of Libav. 6 * 7 * Libav 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 * Libav 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 Libav; 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 26//#define DEBUG 27 28static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values) 29{ 30 uint8_t *cm = ff_cropTbl + MAX_NEG_CROP; 31 uint8_t r, g, b; 32 int i, y, cb, cr; 33 int r_add, g_add, b_add; 34 35 for (i = num_values; i > 0; i--) { 36 y = *ycbcr++; 37 cr = *ycbcr++; 38 cb = *ycbcr++; 39 YUV_TO_RGB1_CCIR(cb, cr); 40 YUV_TO_RGB2_CCIR(r, g, b, y); 41 *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b; 42 } 43} 44 45static int decode_run_2bit(GetBitContext *gb, int *color) 46{ 47 unsigned int v, t; 48 49 v = 0; 50 for (t = 1; v < t && t <= 0x40; t <<= 2) 51 v = (v << 4) | get_bits(gb, 4); 52 *color = v & 3; 53 if (v < 4) { /* Code for fill rest of line */ 54 return INT_MAX; 55 } 56 return v >> 2; 57} 58 59static int decode_run_8bit(GetBitContext *gb, int *color) 60{ 61 int len; 62 int has_run = get_bits1(gb); 63 if (get_bits1(gb)) 64 *color = get_bits(gb, 8); 65 else 66 *color = get_bits(gb, 2); 67 if (has_run) { 68 if (get_bits1(gb)) { 69 len = get_bits(gb, 7); 70 if (len == 0) 71 len = INT_MAX; 72 else 73 len += 9; 74 } else 75 len = get_bits(gb, 3) + 2; 76 } else 77 len = 1; 78 return len; 79} 80 81static int decode_rle(uint8_t *bitmap, int linesize, int w, int h, 82 const uint8_t *buf, int start, int buf_size, int is_8bit) 83{ 84 GetBitContext gb; 85 int bit_len; 86 int x, y, len, color; 87 uint8_t *d; 88 89 bit_len = (buf_size - start) * 8; 90 init_get_bits(&gb, buf + start, bit_len); 91 92 x = 0; 93 y = 0; 94 d = bitmap; 95 for(;;) { 96 if (get_bits_count(&gb) > bit_len) 97 return -1; 98 if (is_8bit) 99 len = decode_run_8bit(&gb, &color); 100 else 101 len = decode_run_2bit(&gb, &color); 102 len = FFMIN(len, w - x); 103 memset(d + x, color, len); 104 x += len; 105 if (x >= w) { 106 y++; 107 if (y >= h) 108 break; 109 d += linesize; 110 x = 0; 111 /* byte align */ 112 align_get_bits(&gb); 113 } 114 } 115 return 0; 116} 117 118static void guess_palette(uint32_t *rgba_palette, 119 uint8_t *colormap, 120 uint8_t *alpha, 121 uint32_t subtitle_color) 122{ 123 uint8_t color_used[16]; 124 int nb_opaque_colors, i, level, j, r, g, b; 125 126 for(i = 0; i < 4; i++) 127 rgba_palette[i] = 0; 128 129 memset(color_used, 0, 16); 130 nb_opaque_colors = 0; 131 for(i = 0; i < 4; i++) { 132 if (alpha[i] != 0 && !color_used[colormap[i]]) { 133 color_used[colormap[i]] = 1; 134 nb_opaque_colors++; 135 } 136 } 137 138 if (nb_opaque_colors == 0) 139 return; 140 141 j = nb_opaque_colors; 142 memset(color_used, 0, 16); 143 for(i = 0; i < 4; i++) { 144 if (alpha[i] != 0) { 145 if (!color_used[colormap[i]]) { 146 level = (0xff * j) / nb_opaque_colors; 147 r = (((subtitle_color >> 16) & 0xff) * level) >> 8; 148 g = (((subtitle_color >> 8) & 0xff) * level) >> 8; 149 b = (((subtitle_color >> 0) & 0xff) * level) >> 8; 150 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24); 151 color_used[colormap[i]] = (i + 1); 152 j--; 153 } else { 154 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) | 155 ((alpha[i] * 17) << 24); 156 } 157 } 158 } 159} 160 161#define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a)) 162 163static int decode_dvd_subtitles(AVSubtitle *sub_header, 164 const uint8_t *buf, int buf_size) 165{ 166 int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos; 167 int big_offsets, offset_size, is_8bit = 0; 168 const uint8_t *yuv_palette = 0; 169 uint8_t colormap[4], alpha[256]; 170 int date; 171 int i; 172 int is_menu = 0; 173 174 if (buf_size < 10) 175 return -1; 176 memset(sub_header, 0, sizeof(*sub_header)); 177 178 if (AV_RB16(buf) == 0) { /* HD subpicture with 4-byte offsets */ 179 big_offsets = 1; 180 offset_size = 4; 181 cmd_pos = 6; 182 } else { 183 big_offsets = 0; 184 offset_size = 2; 185 cmd_pos = 2; 186 } 187 188 cmd_pos = READ_OFFSET(buf + cmd_pos); 189 190 while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) { 191 date = AV_RB16(buf + cmd_pos); 192 next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2); 193 av_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n", 194 cmd_pos, next_cmd_pos, date); 195 pos = cmd_pos + 2 + offset_size; 196 offset1 = -1; 197 offset2 = -1; 198 x1 = y1 = x2 = y2 = 0; 199 while (pos < buf_size) { 200 cmd = buf[pos++]; 201 av_dlog(NULL, "cmd=%02x\n", cmd); 202 switch(cmd) { 203 case 0x00: 204 /* menu subpicture */ 205 is_menu = 1; 206 break; 207 case 0x01: 208 /* set start date */ 209 sub_header->start_display_time = (date << 10) / 90; 210 break; 211 case 0x02: 212 /* set end date */ 213 sub_header->end_display_time = (date << 10) / 90; 214 break; 215 case 0x03: 216 /* set colormap */ 217 if ((buf_size - pos) < 2) 218 goto fail; 219 colormap[3] = buf[pos] >> 4; 220 colormap[2] = buf[pos] & 0x0f; 221 colormap[1] = buf[pos + 1] >> 4; 222 colormap[0] = buf[pos + 1] & 0x0f; 223 pos += 2; 224 break; 225 case 0x04: 226 /* set alpha */ 227 if ((buf_size - pos) < 2) 228 goto fail; 229 alpha[3] = buf[pos] >> 4; 230 alpha[2] = buf[pos] & 0x0f; 231 alpha[1] = buf[pos + 1] >> 4; 232 alpha[0] = buf[pos + 1] & 0x0f; 233 pos += 2; 234 av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]); 235 break; 236 case 0x05: 237 case 0x85: 238 if ((buf_size - pos) < 6) 239 goto fail; 240 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4); 241 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2]; 242 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4); 243 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5]; 244 if (cmd & 0x80) 245 is_8bit = 1; 246 av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2); 247 pos += 6; 248 break; 249 case 0x06: 250 if ((buf_size - pos) < 4) 251 goto fail; 252 offset1 = AV_RB16(buf + pos); 253 offset2 = AV_RB16(buf + pos + 2); 254 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2); 255 pos += 4; 256 break; 257 case 0x86: 258 if ((buf_size - pos) < 8) 259 goto fail; 260 offset1 = AV_RB32(buf + pos); 261 offset2 = AV_RB32(buf + pos + 4); 262 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2); 263 pos += 8; 264 break; 265 266 case 0x83: 267 /* HD set palette */ 268 if ((buf_size - pos) < 768) 269 goto fail; 270 yuv_palette = buf + pos; 271 pos += 768; 272 break; 273 case 0x84: 274 /* HD set contrast (alpha) */ 275 if ((buf_size - pos) < 256) 276 goto fail; 277 for (i = 0; i < 256; i++) 278 alpha[i] = 0xFF - buf[pos+i]; 279 pos += 256; 280 break; 281 282 case 0xff: 283 goto the_end; 284 default: 285 av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd); 286 goto the_end; 287 } 288 } 289 the_end: 290 if (offset1 >= 0) { 291 int w, h; 292 uint8_t *bitmap; 293 294 /* decode the bitmap */ 295 w = x2 - x1 + 1; 296 if (w < 0) 297 w = 0; 298 h = y2 - y1; 299 if (h < 0) 300 h = 0; 301 if (w > 0 && h > 0) { 302 if (sub_header->rects != NULL) { 303 for (i = 0; i < sub_header->num_rects; i++) { 304 av_freep(&sub_header->rects[i]->pict.data[0]); 305 av_freep(&sub_header->rects[i]->pict.data[1]); 306 av_freep(&sub_header->rects[i]); 307 } 308 av_freep(&sub_header->rects); 309 sub_header->num_rects = 0; 310 } 311 312 bitmap = av_malloc(w * h); 313 sub_header->rects = av_mallocz(sizeof(*sub_header->rects)); 314 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect)); 315 sub_header->num_rects = 1; 316 sub_header->rects[0]->pict.data[0] = bitmap; 317 decode_rle(bitmap, w * 2, w, (h + 1) / 2, 318 buf, offset1, buf_size, is_8bit); 319 decode_rle(bitmap + w, w * 2, w, h / 2, 320 buf, offset2, buf_size, is_8bit); 321 sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE); 322 if (is_8bit) { 323 if (yuv_palette == 0) 324 goto fail; 325 sub_header->rects[0]->nb_colors = 256; 326 yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256); 327 } else { 328 sub_header->rects[0]->nb_colors = 4; 329 guess_palette((uint32_t*)sub_header->rects[0]->pict.data[1], 330 colormap, alpha, 0xffff00); 331 } 332 sub_header->rects[0]->x = x1; 333 sub_header->rects[0]->y = y1; 334 sub_header->rects[0]->w = w; 335 sub_header->rects[0]->h = h; 336 sub_header->rects[0]->type = SUBTITLE_BITMAP; 337 sub_header->rects[0]->pict.linesize[0] = w; 338 } 339 } 340 if (next_cmd_pos == cmd_pos) 341 break; 342 cmd_pos = next_cmd_pos; 343 } 344 if (sub_header->num_rects > 0) 345 return is_menu; 346 fail: 347 if (sub_header->rects != NULL) { 348 for (i = 0; i < sub_header->num_rects; i++) { 349 av_freep(&sub_header->rects[i]->pict.data[0]); 350 av_freep(&sub_header->rects[i]->pict.data[1]); 351 av_freep(&sub_header->rects[i]); 352 } 353 av_freep(&sub_header->rects); 354 sub_header->num_rects = 0; 355 } 356 return -1; 357} 358 359static int is_transp(const uint8_t *buf, int pitch, int n, 360 const uint8_t *transp_color) 361{ 362 int i; 363 for(i = 0; i < n; i++) { 364 if (!transp_color[*buf]) 365 return 0; 366 buf += pitch; 367 } 368 return 1; 369} 370 371/* return 0 if empty rectangle, 1 if non empty */ 372static int find_smallest_bounding_rectangle(AVSubtitle *s) 373{ 374 uint8_t transp_color[256]; 375 int y1, y2, x1, x2, y, w, h, i; 376 uint8_t *bitmap; 377 378 if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0) 379 return 0; 380 381 memset(transp_color, 0, 256); 382 for(i = 0; i < s->rects[0]->nb_colors; i++) { 383 if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0) 384 transp_color[i] = 1; 385 } 386 y1 = 0; 387 while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0], 388 1, s->rects[0]->w, transp_color)) 389 y1++; 390 if (y1 == s->rects[0]->h) { 391 av_freep(&s->rects[0]->pict.data[0]); 392 s->rects[0]->w = s->rects[0]->h = 0; 393 return 0; 394 } 395 396 y2 = s->rects[0]->h - 1; 397 while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1, 398 s->rects[0]->w, transp_color)) 399 y2--; 400 x1 = 0; 401 while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0], 402 s->rects[0]->h, transp_color)) 403 x1++; 404 x2 = s->rects[0]->w - 1; 405 while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h, 406 transp_color)) 407 x2--; 408 w = x2 - x1 + 1; 409 h = y2 - y1 + 1; 410 bitmap = av_malloc(w * h); 411 if (!bitmap) 412 return 1; 413 for(y = 0; y < h; y++) { 414 memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w); 415 } 416 av_freep(&s->rects[0]->pict.data[0]); 417 s->rects[0]->pict.data[0] = bitmap; 418 s->rects[0]->pict.linesize[0] = w; 419 s->rects[0]->w = w; 420 s->rects[0]->h = h; 421 s->rects[0]->x += x1; 422 s->rects[0]->y += y1; 423 return 1; 424} 425 426#ifdef DEBUG 427#undef fprintf 428#undef perror 429#undef exit 430static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h, 431 uint32_t *rgba_palette) 432{ 433 int x, y, v; 434 FILE *f; 435 436 f = fopen(filename, "w"); 437 if (!f) { 438 perror(filename); 439 exit(1); 440 } 441 fprintf(f, "P6\n" 442 "%d %d\n" 443 "%d\n", 444 w, h, 255); 445 for(y = 0; y < h; y++) { 446 for(x = 0; x < w; x++) { 447 v = rgba_palette[bitmap[y * w + x]]; 448 putc((v >> 16) & 0xff, f); 449 putc((v >> 8) & 0xff, f); 450 putc((v >> 0) & 0xff, f); 451 } 452 } 453 fclose(f); 454} 455#endif 456 457static int dvdsub_decode(AVCodecContext *avctx, 458 void *data, int *data_size, 459 AVPacket *avpkt) 460{ 461 const uint8_t *buf = avpkt->data; 462 int buf_size = avpkt->size; 463 AVSubtitle *sub = data; 464 int is_menu; 465 466 is_menu = decode_dvd_subtitles(sub, buf, buf_size); 467 468 if (is_menu < 0) { 469 no_subtitle: 470 *data_size = 0; 471 472 return buf_size; 473 } 474 if (!is_menu && find_smallest_bounding_rectangle(sub) == 0) 475 goto no_subtitle; 476 477#if defined(DEBUG) 478 av_dlog(NULL, "start=%d ms end =%d ms\n", 479 sub->start_display_time, 480 sub->end_display_time); 481 ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0], 482 sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]); 483#endif 484 485 *data_size = 1; 486 return buf_size; 487} 488 489AVCodec ff_dvdsub_decoder = { 490 .name = "dvdsub", 491 .type = AVMEDIA_TYPE_SUBTITLE, 492 .id = CODEC_ID_DVD_SUBTITLE, 493 .decode = dvdsub_decode, 494 .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"), 495}; 496