libavcodec/dvdsubdec.c

   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
  22 #include "avcodec.h"
  23 #include "bitstream.h"
  24 #include "internal.h"
  25
  26 #include "libavutil/attributes.h"
  27 #include "libavutil/colorspace.h"
  28 #include "libavutil/imgutils.h"
  29 #include "libavutil/avstring.h"
  30
  31 typedef struct DVDSubContext {
  32     uint32_t palette[16];
  33     int      has_palette;
  34 } DVDSubContext;
  35
  36 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
  37 {
  38     const uint8_t *cm = ff_crop_tab + MAX_NEG_CROP;
  39     uint8_t r, g, b;
  40     int i, y, cb, cr;
  41     int r_add, g_add, b_add;
  42
  43     for (i = num_values; i > 0; i--) {
  44         y = *ycbcr++;
  45         cr = *ycbcr++;
  46         cb = *ycbcr++;
  47         YUV_TO_RGB1_CCIR(cb, cr);
  48         YUV_TO_RGB2_CCIR(r, g, b, y);
  49         *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;
  50     }
  51 }
  52
  53 static int decode_run_2bit(BitstreamContext *bc, int *color)
  54 {
  55     unsigned int v, t;
  56
  57     v = 0;
  58     for (t = 1; v < t && t <= 0x40; t <<= 2)
  59         v = (v << 4) | bitstream_read(bc, 4);
  60     *color = v & 3;
  61     if (v < 4) { /* Code for fill rest of line */
  62         return INT_MAX;
  63     }
  64     return v >> 2;
  65 }
  66
  67 static int decode_run_8bit(BitstreamContext *bc, int *color)
  68 {
  69     int len;
  70     int has_run = bitstream_read_bit(bc);
  71     if (bitstream_read_bit(bc))
  72         *color = bitstream_read(bc, 8);
  73     else
  74         *color = bitstream_read(bc, 2);
  75     if (has_run) {
  76         if (bitstream_read_bit(bc)) {
  77             len = bitstream_read(bc, 7);
  78             if (len == 0)
  79                 len = INT_MAX;
  80             else
  81                 len += 9;
  82         } else
  83             len = bitstream_read(bc, 3) + 2;
  84     } else
  85         len = 1;
  86     return len;
  87 }
  88
  89 static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
  90                       const uint8_t *buf, int start, int buf_size, int is_8bit)
  91 {
  92     BitstreamContext bc;
  93     int bit_len;
  94     int x, y, len, color;
  95     uint8_t *d;
  96
  97     bit_len = (buf_size - start) * 8;
  98     bitstream_init(&bc, buf + start, bit_len);
  99
 100     x = 0;
 101     y = 0;
 102     d = bitmap;
 103     for(;;) {
 104         if (bitstream_tell(&bc) > bit_len)
 105             return -1;
 106         if (is_8bit)
 107             len = decode_run_8bit(&bc, &color);
 108         else
 109             len = decode_run_2bit(&bc, &color);
 110         len = FFMIN(len, w - x);
 111         memset(d + x, color, len);
 112         x += len;
 113         if (x >= w) {
 114             y++;
 115             if (y >= h)
 116                 break;
 117             d += linesize;
 118             x = 0;
 119             /* byte align */
 120             bitstream_align(&bc);
 121         }
 122     }
 123     return 0;
 124 }
 125
 126 static void guess_palette(DVDSubContext* ctx,
 127                           uint32_t *rgba_palette,
 128                           uint8_t *colormap,
 129                           uint8_t *alpha,
 130                           uint32_t subtitle_color)
 131 {
 132     uint8_t color_used[16] = { 0 };
 133     int nb_opaque_colors, i, level, j, r, g, b;
 134
 135     if (ctx->has_palette) {
 136         for (i = 0; i < 4; i++)
 137             rgba_palette[i] = (ctx->palette[colormap[i]] & 0x00ffffff)
 138                               | ((alpha[i] * 17) << 24);
 139         return;
 140     }
 141
 142     for(i = 0; i < 4; i++)
 143         rgba_palette[i] = 0;
 144
 145     nb_opaque_colors = 0;
 146     for(i = 0; i < 4; i++) {
 147         if (alpha[i] != 0 && !color_used[colormap[i]]) {
 148             color_used[colormap[i]] = 1;
 149             nb_opaque_colors++;
 150         }
 151     }
 152
 153     if (nb_opaque_colors == 0)
 154         return;
 155
 156     j = nb_opaque_colors;
 157     memset(color_used, 0, 16);
 158     for(i = 0; i < 4; i++) {
 159         if (alpha[i] != 0) {
 160             if (!color_used[colormap[i]])  {
 161                 level = (0xff * j) / nb_opaque_colors;
 162                 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
 163                 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
 164                 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
 165                 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
 166                 color_used[colormap[i]] = (i + 1);
 167                 j--;
 168             } else {
 169                 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
 170                                     ((alpha[i] * 17) << 24);
 171             }
 172         }
 173     }
 174 }
 175
 176 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
 177
 178 static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,
 179                                 const uint8_t *buf, int buf_size)
 180 {
 181     int cmd_pos, pos, cmd, x1, y1, x2, y2, next_cmd_pos;
 182     int big_offsets, offset_size, is_8bit = 0;
 183     const uint8_t *yuv_palette = 0;
 184     uint8_t colormap[4] = { 0 }, alpha[256] = { 0 };
 185     int date;
 186     int i;
 187     int is_menu = 0;
 188     int64_t offset1, offset2;
 189
 190     if (buf_size < 10)
 191         return -1;
 192     memset(sub_header, 0, sizeof(*sub_header));
 193
 194     if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
 195         big_offsets = 1;
 196         offset_size = 4;
 197         cmd_pos = 6;
 198     } else {
 199         big_offsets = 0;
 200         offset_size = 2;
 201         cmd_pos = 2;
 202     }
 203
 204     cmd_pos = READ_OFFSET(buf + cmd_pos);
 205
 206     while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) {
 207         date = AV_RB16(buf + cmd_pos);
 208         next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
 209         ff_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",
 210                 cmd_pos, next_cmd_pos, date);
 211         pos = cmd_pos + 2 + offset_size;
 212         offset1 = -1;
 213         offset2 = -1;
 214         x1 = y1 = x2 = y2 = 0;
 215         while (pos < buf_size) {
 216             cmd = buf[pos++];
 217             ff_dlog(NULL, "cmd=%02x\n", cmd);
 218             switch(cmd) {
 219             case 0x00:
 220                 /* menu subpicture */
 221                 is_menu = 1;
 222                 break;
 223             case 0x01:
 224                 /* set start date */
 225                 sub_header->start_display_time = (date << 10) / 90;
 226                 break;
 227             case 0x02:
 228                 /* set end date */
 229                 sub_header->end_display_time = (date << 10) / 90;
 230                 break;
 231             case 0x03:
 232                 /* set colormap */
 233                 if ((buf_size - pos) < 2)
 234                     goto fail;
 235                 colormap[3] = buf[pos] >> 4;
 236                 colormap[2] = buf[pos] & 0x0f;
 237                 colormap[1] = buf[pos + 1] >> 4;
 238                 colormap[0] = buf[pos + 1] & 0x0f;
 239                 pos += 2;
 240                 break;
 241             case 0x04:
 242                 /* set alpha */
 243                 if ((buf_size - pos) < 2)
 244                     goto fail;
 245                 alpha[3] = buf[pos] >> 4;
 246                 alpha[2] = buf[pos] & 0x0f;
 247                 alpha[1] = buf[pos + 1] >> 4;
 248                 alpha[0] = buf[pos + 1] & 0x0f;
 249                 pos += 2;
 250                 ff_dlog(NULL, "alpha=%"PRIx8"%"PRIx8"%"PRIx8"%"PRIx8"\n",
 251                         alpha[0], alpha[1], alpha[2], alpha[3]);
 252                 break;
 253             case 0x05:
 254             case 0x85:
 255                 if ((buf_size - pos) < 6)
 256                     goto fail;
 257                 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
 258                 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
 259                 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
 260                 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
 261                 if (cmd & 0x80)
 262                     is_8bit = 1;
 263                 ff_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);
 264                 pos += 6;
 265                 break;
 266             case 0x06:
 267                 if ((buf_size - pos) < 4)
 268                     goto fail;
 269                 offset1 = AV_RB16(buf + pos);
 270                 offset2 = AV_RB16(buf + pos + 2);
 271                 ff_dlog(NULL, "offset1=0x%04"PRIx64" offset2=0x%04"PRIx64"\n", offset1, offset2);
 272                 pos += 4;
 273                 break;
 274             case 0x86:
 275                 if ((buf_size - pos) < 8)
 276                     goto fail;
 277                 offset1 = AV_RB32(buf + pos);
 278                 offset2 = AV_RB32(buf + pos + 4);
 279                 ff_dlog(NULL, "offset1=0x%04"PRIx64" offset2=0x%04"PRIx64"\n", offset1, offset2);
 280                 pos += 8;
 281                 break;
 282
 283             case 0x83:
 284                 /* HD set palette */
 285                 if ((buf_size - pos) < 768)
 286                     goto fail;
 287                 yuv_palette = buf + pos;
 288                 pos += 768;
 289                 break;
 290             case 0x84:
 291                 /* HD set contrast (alpha) */
 292                 if ((buf_size - pos) < 256)
 293                     goto fail;
 294                 for (i = 0; i < 256; i++)
 295                     alpha[i] = 0xFF - buf[pos+i];
 296                 pos += 256;
 297                 break;
 298
 299             case 0xff:
 300                 goto the_end;
 301             default:
 302                 ff_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);
 303                 goto the_end;
 304             }
 305         }
 306     the_end:
 307         if (offset1 >= buf_size || offset2 >= buf_size)
 308             goto fail;
 309
 310         if (offset1 >= 0) {
 311             int w, h;
 312             uint8_t *bitmap;
 313
 314             /* decode the bitmap */
 315             w = x2 - x1 + 1;
 316             if (w < 0)
 317                 w = 0;
 318             h = y2 - y1;
 319             if (h < 0)
 320                 h = 0;
 321             if (w > 0 && h > 0) {
 322                 if (sub_header->rects) {
 323                     for (i = 0; i < sub_header->num_rects; i++) {
 324                         av_freep(&sub_header->rects[i]->data[0]);
 325                         av_freep(&sub_header->rects[i]->data[1]);
 326                         av_freep(&sub_header->rects[i]);
 327                     }
 328                     av_freep(&sub_header->rects);
 329                     sub_header->num_rects = 0;
 330                 }
 331
 332                 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));
 333                 if (!sub_header->rects)
 334                     goto fail;
 335                 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));
 336                 if (!sub_header->rects[0])
 337                     goto fail;
 338                 sub_header->num_rects = 1;
 339                 bitmap = sub_header->rects[0]->data[0] = av_malloc(w * h);
 340                 if (!bitmap)
 341                     goto fail;
 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]->data[1] = av_mallocz(AVPALETTE_SIZE);
 347                 if (!sub_header->rects[0]->data[1])
 348                     goto fail;
 349                 if (is_8bit) {
 350                     if (yuv_palette == 0)
 351                         goto fail;
 352                     sub_header->rects[0]->nb_colors = 256;
 353                     yuv_a_to_rgba(yuv_palette, alpha,
 354                                   (uint32_t *)sub_header->rects[0]->data[1],
 355                                   256);
 356                 } else {
 357                     sub_header->rects[0]->nb_colors = 4;
 358                     guess_palette(ctx,
 359                                   (uint32_t *)sub_header->rects[0]->data[1],
 360                                   colormap, alpha, 0xffff00);
 361                 }
 362                 sub_header->rects[0]->x = x1;
 363                 sub_header->rects[0]->y = y1;
 364                 sub_header->rects[0]->w = w;
 365                 sub_header->rects[0]->h = h;
 366                 sub_header->rects[0]->type = SUBTITLE_BITMAP;
 367                 sub_header->rects[0]->linesize[0] = w;
 368
 369 #if FF_API_AVPICTURE
 370 FF_DISABLE_DEPRECATION_WARNINGS
 371 {
 372                 int j;
 373                 AVSubtitleRect *rect;
 374                 rect = sub_header->rects[0];
 375                 for (j = 0; j < 4; j++) {
 376                     rect->pict.data[j] = rect->data[j];
 377                     rect->pict.linesize[j] = rect->linesize[j];
 378                 }
 379 }
 380 FF_ENABLE_DEPRECATION_WARNINGS
 381 #endif
 382             }
 383         }
 384         if (next_cmd_pos == cmd_pos)
 385             break;
 386         cmd_pos = next_cmd_pos;
 387     }
 388     if (sub_header->num_rects > 0)
 389         return is_menu;
 390  fail:
 391     if (!sub_header->rects) {
 392         for (i = 0; i < sub_header->num_rects; i++) {
 393             av_freep(&sub_header->rects[i]->data[0]);
 394             av_freep(&sub_header->rects[i]->data[1]);
 395             av_freep(&sub_header->rects[i]);
 396         }
 397         av_freep(&sub_header->rects);
 398         sub_header->num_rects = 0;
 399     }
 400     return -1;
 401 }
 402
 403 static int is_transp(const uint8_t *buf, int pitch, int n,
 404                      const uint8_t *transp_color)
 405 {
 406     int i;
 407     for(i = 0; i < n; i++) {
 408         if (!transp_color[*buf])
 409             return 0;
 410         buf += pitch;
 411     }
 412     return 1;
 413 }
 414
 415 /* return 0 if empty rectangle, 1 if non empty */
 416 static int find_smallest_bounding_rectangle(AVSubtitle *s)
 417 {
 418     uint8_t transp_color[256] = { 0 };
 419     int y1, y2, x1, x2, y, w, h, i;
 420     uint8_t *bitmap;
 421
 422     if (s->num_rects == 0 || !s->rects || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)
 423         return 0;
 424
 425     for(i = 0; i < s->rects[0]->nb_colors; i++) {
 426         if ((((uint32_t *)s->rects[0]->data[1])[i] >> 24) == 0)
 427             transp_color[i] = 1;
 428     }
 429     y1 = 0;
 430     while (y1 < s->rects[0]->h && is_transp(s->rects[0]->data[0] + y1 * s->rects[0]->linesize[0],
 431                                   1, s->rects[0]->w, transp_color))
 432         y1++;
 433     if (y1 == s->rects[0]->h) {
 434         av_freep(&s->rects[0]->data[0]);
 435         s->rects[0]->w = s->rects[0]->h = 0;
 436         return 0;
 437     }
 438
 439     y2 = s->rects[0]->h - 1;
 440     while (y2 > 0 && is_transp(s->rects[0]->data[0] + y2 * s->rects[0]->linesize[0], 1,
 441                                s->rects[0]->w, transp_color))
 442         y2--;
 443     x1 = 0;
 444     while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->data[0] + x1, s->rects[0]->linesize[0],
 445                                         s->rects[0]->h, transp_color))
 446         x1++;
 447     x2 = s->rects[0]->w - 1;
 448     while (x2 > 0 && is_transp(s->rects[0]->data[0] + x2, s->rects[0]->linesize[0], s->rects[0]->h,
 449                                   transp_color))
 450         x2--;
 451     w = x2 - x1 + 1;
 452     h = y2 - y1 + 1;
 453     bitmap = av_malloc(w * h);
 454     if (!bitmap)
 455         return 1;
 456     for(y = 0; y < h; y++) {
 457         memcpy(bitmap + w * y, s->rects[0]->data[0] + x1 + (y1 + y) * s->rects[0]->linesize[0], w);
 458     }
 459     av_freep(&s->rects[0]->data[0]);
 460     s->rects[0]->data[0] = bitmap;
 461     s->rects[0]->linesize[0] = w;
 462     s->rects[0]->w = w;
 463     s->rects[0]->h = h;
 464     s->rects[0]->x += x1;
 465     s->rects[0]->y += y1;
 466     return 1;
 467 }
 468
 469 #ifdef DEBUG
 470 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
 471                      uint32_t *rgba_palette)
 472 {
 473     int x, y, v;
 474     FILE *f;
 475
 476     f = fopen(filename, "w");
 477     if (!f) {
 478         perror(filename);
 479         exit(1);
 480     }
 481     fprintf(f, "P6\n"
 482             "%d %d\n"
 483             "%d\n",
 484             w, h, 255);
 485     for(y = 0; y < h; y++) {
 486         for(x = 0; x < w; x++) {
 487             v = rgba_palette[bitmap[y * w + x]];
 488             putc((v >> 16) & 0xff, f);
 489             putc((v >> 8) & 0xff, f);
 490             putc((v >> 0) & 0xff, f);
 491         }
 492     }
 493     fclose(f);
 494 }
 495 #endif
 496
 497 static int dvdsub_decode(AVCodecContext *avctx,
 498                          void *data, int *data_size,
 499                          AVPacket *avpkt)
 500 {
 501     DVDSubContext *ctx = avctx->priv_data;
 502     const uint8_t *buf = avpkt->data;
 503     int buf_size = avpkt->size;
 504     AVSubtitle *sub = data;
 505     int is_menu;
 506
 507     is_menu = decode_dvd_subtitles(ctx, sub, buf, buf_size);
 508
 509     if (is_menu < 0) {
 510     no_subtitle:
 511         *data_size = 0;
 512
 513         return buf_size;
 514     }
 515     if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
 516         goto no_subtitle;
 517
 518 #if defined(DEBUG)
 519     ff_dlog(NULL, "start=%"PRIu32" ms end =%"PRIu32" ms\n",
 520             sub->start_display_time,
 521             sub->end_display_time);
 522     ppm_save("/tmp/a.ppm", sub->rects[0]->data[0],
 523              sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->data[1]);
 524 #endif
 525
 526     *data_size = 1;
 527     return buf_size;
 528 }
 529
 530 static av_cold int dvdsub_init(AVCodecContext *avctx)
 531 {
 532     DVDSubContext *ctx = avctx->priv_data;
 533     char *data, *cur;
 534     int ret = 0;
 535
 536     if (!avctx->extradata || !avctx->extradata_size)
 537         return 0;
 538
 539     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';
 544     cur = data;
 545
 546     while (*cur) {
 547         if (strncmp("palette:", cur, 8) == 0) {
 548             int i;
 549             char *p = cur + 8;
 550             ctx->has_palette = 1;
 551             for (i = 0; i < 16; i++) {
 552                 ctx->palette[i] = strtoul(p, &p, 16);
 553                 while (*p == ',' || av_isspace(*p))
 554                     p++;
 555             }
 556         } else if (!strncmp("size:", cur, 5)) {
 557             int w, h;
 558             if (sscanf(cur + 5, "%dx%d", &w, &h) == 2) {
 559                ret = ff_set_dimensions(avctx, w, h);
 560                if (ret < 0)
 561                    goto fail;
 562             }
 563         }
 564         cur += strcspn(cur, "\n\r");
 565         cur += strspn(cur, "\n\r");
 566     }
 567
 568 fail:
 569     av_free(data);
 570     return ret;
 571 }
 572
 573 AVCodec ff_dvdsub_decoder = {
 574     .name           = "dvdsub",
 575     .long_name      = NULL_IF_CONFIG_SMALL("DVD subtitles"),
 576     .type           = AVMEDIA_TYPE_SUBTITLE,
 577     .id             = AV_CODEC_ID_DVD_SUBTITLE,
 578     .priv_data_size = sizeof(DVDSubContext),
 579     .init           = dvdsub_init,
 580     .decode         = dvdsub_decode,
 581 };