libavcodec/dvdsubdec.c

   1 /*
   2  * DVD subtitle decoding for ffmpeg
   3  * Copyright (c) 2005 Fabrice Bellard
   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 "colorspace.h"
  24 #include "dsputil.h"
  25
  26 //#define DEBUG
  27
  28 static 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         cb = *ycbcr++;
  38         cr = *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
  45 static 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
  59 static 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
  81 static 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
 118 static 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
 163 static 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     sub_header->rects = NULL;
 177     sub_header->num_rects = 0;
 178     sub_header->format = 0;
 179     sub_header->start_display_time = 0;
 180     sub_header->end_display_time = 0;
 181
 182     if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
 183         big_offsets = 1;
 184         offset_size = 4;
 185         cmd_pos = 6;
 186     } else {
 187         big_offsets = 0;
 188         offset_size = 2;
 189         cmd_pos = 2;
 190     }
 191
 192     cmd_pos = READ_OFFSET(buf + cmd_pos);
 193
 194     while ((cmd_pos + 2 + offset_size) < buf_size) {
 195         date = AV_RB16(buf + cmd_pos);
 196         next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
 197         dprintf(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",
 198                 cmd_pos, next_cmd_pos, date);
 199         pos = cmd_pos + 2 + offset_size;
 200         offset1 = -1;
 201         offset2 = -1;
 202         x1 = y1 = x2 = y2 = 0;
 203         while (pos < buf_size) {
 204             cmd = buf[pos++];
 205             dprintf(NULL, "cmd=%02x\n", cmd);
 206             switch(cmd) {
 207             case 0x00:
 208                 /* menu subpicture */
 209                 is_menu = 1;
 210                 break;
 211             case 0x01:
 212                 /* set start date */
 213                 sub_header->start_display_time = (date << 10) / 90;
 214                 break;
 215             case 0x02:
 216                 /* set end date */
 217                 sub_header->end_display_time = (date << 10) / 90;
 218                 break;
 219             case 0x03:
 220                 /* set colormap */
 221                 if ((buf_size - pos) < 2)
 222                     goto fail;
 223                 colormap[3] = buf[pos] >> 4;
 224                 colormap[2] = buf[pos] & 0x0f;
 225                 colormap[1] = buf[pos + 1] >> 4;
 226                 colormap[0] = buf[pos + 1] & 0x0f;
 227                 pos += 2;
 228                 break;
 229             case 0x04:
 230                 /* set alpha */
 231                 if ((buf_size - pos) < 2)
 232                     goto fail;
 233                 alpha[3] = buf[pos] >> 4;
 234                 alpha[2] = buf[pos] & 0x0f;
 235                 alpha[1] = buf[pos + 1] >> 4;
 236                 alpha[0] = buf[pos + 1] & 0x0f;
 237                 pos += 2;
 238             dprintf(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
 239                 break;
 240             case 0x05:
 241             case 0x85:
 242                 if ((buf_size - pos) < 6)
 243                     goto fail;
 244                 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
 245                 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
 246                 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
 247                 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
 248                 if (cmd & 0x80)
 249                     is_8bit = 1;
 250                 dprintf(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);
 251                 pos += 6;
 252                 break;
 253             case 0x06:
 254                 if ((buf_size - pos) < 4)
 255                     goto fail;
 256                 offset1 = AV_RB16(buf + pos);
 257                 offset2 = AV_RB16(buf + pos + 2);
 258                 dprintf(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
 259                 pos += 4;
 260                 break;
 261             case 0x86:
 262                 if ((buf_size - pos) < 8)
 263                     goto fail;
 264                 offset1 = AV_RB32(buf + pos);
 265                 offset2 = AV_RB32(buf + pos + 4);
 266                 dprintf(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
 267                 pos += 8;
 268                 break;
 269
 270             case 0x83:
 271                 /* HD set palette */
 272                 if ((buf_size - pos) < 768)
 273                     goto fail;
 274                 yuv_palette = buf + pos;
 275                 pos += 768;
 276                 break;
 277             case 0x84:
 278                 /* HD set contrast (alpha) */
 279                 if ((buf_size - pos) < 256)
 280                     goto fail;
 281                 for (i = 0; i < 256; i++)
 282                     alpha[i] = 0xFF - buf[pos+i];
 283                 pos += 256;
 284                 break;
 285
 286             case 0xff:
 287                 goto the_end;
 288             default:
 289                 dprintf(NULL, "unrecognised subpicture command 0x%x\n", cmd);
 290                 goto the_end;
 291             }
 292         }
 293     the_end:
 294         if (offset1 >= 0) {
 295             int w, h;
 296             uint8_t *bitmap;
 297
 298             /* decode the bitmap */
 299             w = x2 - x1 + 1;
 300             if (w < 0)
 301                 w = 0;
 302             h = y2 - y1;
 303             if (h < 0)
 304                 h = 0;
 305             if (w > 0 && h > 0) {
 306                 if (sub_header->rects != NULL) {
 307                     for (i = 0; i < sub_header->num_rects; i++) {
 308                         av_freep(&sub_header->rects[i]->pict.data[0]);
 309                         av_freep(&sub_header->rects[i]->pict.data[1]);
 310                         av_freep(&sub_header->rects[i]);
 311                     }
 312                     av_freep(&sub_header->rects);
 313                     sub_header->num_rects = 0;
 314                 }
 315
 316                 bitmap = av_malloc(w * h);
 317                 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));
 318                 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));
 319                 sub_header->num_rects = 1;
 320                 sub_header->rects[0]->pict.data[0] = bitmap;
 321                 decode_rle(bitmap, w * 2, w, (h + 1) / 2,
 322                            buf, offset1, buf_size, is_8bit);
 323                 decode_rle(bitmap + w, w * 2, w, h / 2,
 324                            buf, offset2, buf_size, is_8bit);
 325                 if (is_8bit) {
 326                     if (yuv_palette == 0)
 327                         goto fail;
 328                     sub_header->rects[0]->pict.data[1] = av_malloc(256 * 4);
 329                     sub_header->rects[0]->nb_colors = 256;
 330                     yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);
 331                 } else {
 332                     sub_header->rects[0]->pict.data[1] = av_malloc(4 * 4);
 333                     sub_header->rects[0]->nb_colors = 4;
 334                     guess_palette((uint32_t*)sub_header->rects[0]->pict.data[1],
 335                                   colormap, alpha, 0xffff00);
 336                 }
 337                 sub_header->rects[0]->x = x1;
 338                 sub_header->rects[0]->y = y1;
 339                 sub_header->rects[0]->w = w;
 340                 sub_header->rects[0]->h = h;
 341                 sub_header->rects[0]->type = SUBTITLE_BITMAP;
 342                 sub_header->rects[0]->pict.linesize[0] = w;
 343             }
 344         }
 345         if (next_cmd_pos == cmd_pos)
 346             break;
 347         cmd_pos = next_cmd_pos;
 348     }
 349     if (sub_header->num_rects > 0)
 350         return is_menu;
 351  fail:
 352     if (sub_header->rects != NULL) {
 353         for (i = 0; i < sub_header->num_rects; i++) {
 354             av_freep(&sub_header->rects[i]->pict.data[0]);
 355             av_freep(&sub_header->rects[i]->pict.data[1]);
 356             av_freep(&sub_header->rects[i]);
 357         }
 358         av_freep(&sub_header->rects);
 359         sub_header->num_rects = 0;
 360     }
 361     return -1;
 362 }
 363
 364 static int is_transp(const uint8_t *buf, int pitch, int n,
 365                      const uint8_t *transp_color)
 366 {
 367     int i;
 368     for(i = 0; i < n; i++) {
 369         if (!transp_color[*buf])
 370             return 0;
 371         buf += pitch;
 372     }
 373     return 1;
 374 }
 375
 376 /* return 0 if empty rectangle, 1 if non empty */
 377 static int find_smallest_bounding_rectangle(AVSubtitle *s)
 378 {
 379     uint8_t transp_color[256];
 380     int y1, y2, x1, x2, y, w, h, i;
 381     uint8_t *bitmap;
 382
 383     if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)
 384         return 0;
 385
 386     memset(transp_color, 0, 256);
 387     for(i = 0; i < s->rects[0]->nb_colors; i++) {
 388         if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)
 389             transp_color[i] = 1;
 390     }
 391     y1 = 0;
 392     while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],
 393                                   1, s->rects[0]->w, transp_color))
 394         y1++;
 395     if (y1 == s->rects[0]->h) {
 396         av_freep(&s->rects[0]->pict.data[0]);
 397         s->rects[0]->w = s->rects[0]->h = 0;
 398         return 0;
 399     }
 400
 401     y2 = s->rects[0]->h - 1;
 402     while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,
 403                                s->rects[0]->w, transp_color))
 404         y2--;
 405     x1 = 0;
 406     while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],
 407                                         s->rects[0]->h, transp_color))
 408         x1++;
 409     x2 = s->rects[0]->w - 1;
 410     while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,
 411                                   transp_color))
 412         x2--;
 413     w = x2 - x1 + 1;
 414     h = y2 - y1 + 1;
 415     bitmap = av_malloc(w * h);
 416     if (!bitmap)
 417         return 1;
 418     for(y = 0; y < h; y++) {
 419         memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);
 420     }
 421     av_freep(&s->rects[0]->pict.data[0]);
 422     s->rects[0]->pict.data[0] = bitmap;
 423     s->rects[0]->pict.linesize[0] = w;
 424     s->rects[0]->w = w;
 425     s->rects[0]->h = h;
 426     s->rects[0]->x += x1;
 427     s->rects[0]->y += y1;
 428     return 1;
 429 }
 430
 431 #ifdef DEBUG
 432 #undef fprintf
 433 #undef perror
 434 #undef exit
 435 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
 436                      uint32_t *rgba_palette)
 437 {
 438     int x, y, v;
 439     FILE *f;
 440
 441     f = fopen(filename, "w");
 442     if (!f) {
 443         perror(filename);
 444         exit(1);
 445     }
 446     fprintf(f, "P6\n"
 447             "%d %d\n"
 448             "%d\n",
 449             w, h, 255);
 450     for(y = 0; y < h; y++) {
 451         for(x = 0; x < w; x++) {
 452             v = rgba_palette[bitmap[y * w + x]];
 453             putc((v >> 16) & 0xff, f);
 454             putc((v >> 8) & 0xff, f);
 455             putc((v >> 0) & 0xff, f);
 456         }
 457     }
 458     fclose(f);
 459 }
 460 #endif
 461
 462 static int dvdsub_decode(AVCodecContext *avctx,
 463                          void *data, int *data_size,
 464                          AVPacket *avpkt)
 465 {
 466     const uint8_t *buf = avpkt->data;
 467     int buf_size = avpkt->size;
 468     AVSubtitle *sub = (void *)data;
 469     int is_menu;
 470
 471     is_menu = decode_dvd_subtitles(sub, buf, buf_size);
 472
 473     if (is_menu < 0) {
 474     no_subtitle:
 475         *data_size = 0;
 476
 477         return buf_size;
 478     }
 479     if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
 480         goto no_subtitle;
 481
 482 #if defined(DEBUG)
 483     dprintf(NULL, "start=%d ms end =%d ms\n",
 484             sub->start_display_time,
 485             sub->end_display_time);
 486     ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0],
 487              sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]);
 488 #endif
 489
 490     *data_size = 1;
 491     return buf_size;
 492 }
 493
 494 AVCodec dvdsub_decoder = {
 495     "dvdsub",
 496     CODEC_TYPE_SUBTITLE,
 497     CODEC_ID_DVD_SUBTITLE,
 498     0,
 499     NULL,
 500     NULL,
 501     NULL,
 502     dvdsub_decode,
 503     .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
 504 };