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 "bitstream.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->start_display_time = 0;
 179     sub_header->end_display_time = 0;
 180
 181     if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
 182         big_offsets = 1;
 183         offset_size = 4;
 184         cmd_pos = 6;
 185     } else {
 186         big_offsets = 0;
 187         offset_size = 2;
 188         cmd_pos = 2;
 189     }
 190
 191     cmd_pos = READ_OFFSET(buf + cmd_pos);
 192
 193     while ((cmd_pos + 2 + offset_size) < buf_size) {
 194         date = AV_RB16(buf + cmd_pos);
 195         next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
 196 #ifdef DEBUG
 197         av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
 198                cmd_pos, next_cmd_pos, date);
 199 #endif
 200         pos = cmd_pos + 2 + offset_size;
 201         offset1 = -1;
 202         offset2 = -1;
 203         x1 = y1 = x2 = y2 = 0;
 204         while (pos < buf_size) {
 205             cmd = buf[pos++];
 206 #ifdef DEBUG
 207             av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
 208 #endif
 209             switch(cmd) {
 210             case 0x00:
 211                 /* menu subpicture */
 212                 is_menu = 1;
 213                 break;
 214             case 0x01:
 215                 /* set start date */
 216                 sub_header->start_display_time = (date << 10) / 90;
 217                 break;
 218             case 0x02:
 219                 /* set end date */
 220                 sub_header->end_display_time = (date << 10) / 90;
 221                 break;
 222             case 0x03:
 223                 /* set colormap */
 224                 if ((buf_size - pos) < 2)
 225                     goto fail;
 226                 colormap[3] = buf[pos] >> 4;
 227                 colormap[2] = buf[pos] & 0x0f;
 228                 colormap[1] = buf[pos + 1] >> 4;
 229                 colormap[0] = buf[pos + 1] & 0x0f;
 230                 pos += 2;
 231                 break;
 232             case 0x04:
 233                 /* set alpha */
 234                 if ((buf_size - pos) < 2)
 235                     goto fail;
 236                 alpha[3] = buf[pos] >> 4;
 237                 alpha[2] = buf[pos] & 0x0f;
 238                 alpha[1] = buf[pos + 1] >> 4;
 239                 alpha[0] = buf[pos + 1] & 0x0f;
 240                 pos += 2;
 241 #ifdef DEBUG
 242             av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
 243 #endif
 244                 break;
 245             case 0x05:
 246             case 0x85:
 247                 if ((buf_size - pos) < 6)
 248                     goto fail;
 249                 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
 250                 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
 251                 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
 252                 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
 253                 if (cmd & 0x80)
 254                     is_8bit = 1;
 255 #ifdef DEBUG
 256                 av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
 257                        x1, x2, y1, y2);
 258 #endif
 259                 pos += 6;
 260                 break;
 261             case 0x06:
 262                 if ((buf_size - pos) < 4)
 263                     goto fail;
 264                 offset1 = AV_RB16(buf + pos);
 265                 offset2 = AV_RB16(buf + pos + 2);
 266 #ifdef DEBUG
 267                 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
 268 #endif
 269                 pos += 4;
 270                 break;
 271             case 0x86:
 272                 if ((buf_size - pos) < 8)
 273                     goto fail;
 274                 offset1 = AV_RB32(buf + pos);
 275                 offset2 = AV_RB32(buf + pos + 4);
 276 #ifdef DEBUG
 277                 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
 278 #endif
 279                 pos += 8;
 280                 break;
 281
 282             case 0x83:
 283                 /* HD set palette */
 284                 if ((buf_size - pos) < 768)
 285                     goto fail;
 286                 yuv_palette = buf + pos;
 287                 pos += 768;
 288                 break;
 289             case 0x84:
 290                 /* HD set contrast (alpha) */
 291                 if ((buf_size - pos) < 256)
 292                     goto fail;
 293                 for (i = 0; i < 256; i++)
 294                     alpha[i] = 0xFF - buf[pos+i];
 295                 pos += 256;
 296                 break;
 297
 298             case 0xff:
 299                 goto the_end;
 300             default:
 301 #ifdef DEBUG
 302                 av_log(NULL, AV_LOG_INFO, "unrecognised subpicture command 0x%x\n", cmd);
 303 #endif
 304                 goto the_end;
 305             }
 306         }
 307     the_end:
 308         if (offset1 >= 0) {
 309             int w, h;
 310             uint8_t *bitmap;
 311
 312             /* decode the bitmap */
 313             w = x2 - x1 + 1;
 314             if (w < 0)
 315                 w = 0;
 316             h = y2 - y1;
 317             if (h < 0)
 318                 h = 0;
 319             if (w > 0 && h > 0) {
 320                 if (sub_header->rects != NULL) {
 321                     for (i = 0; i < sub_header->num_rects; i++) {
 322                         av_free(sub_header->rects[i].bitmap);
 323                         av_free(sub_header->rects[i].rgba_palette);
 324                     }
 325                     av_freep(&sub_header->rects);
 326                     sub_header->num_rects = 0;
 327                 }
 328
 329                 bitmap = av_malloc(w * h);
 330                 sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
 331                 sub_header->num_rects = 1;
 332                 sub_header->rects[0].bitmap = bitmap;
 333                 decode_rle(bitmap, w * 2, w, (h + 1) / 2,
 334                            buf, offset1, buf_size, is_8bit);
 335                 decode_rle(bitmap + w, w * 2, w, h / 2,
 336                            buf, offset2, buf_size, is_8bit);
 337                 if (is_8bit) {
 338                     if (yuv_palette == 0)
 339                         goto fail;
 340                     sub_header->rects[0].rgba_palette = av_malloc(256 * 4);
 341                     sub_header->rects[0].nb_colors = 256;
 342                     yuv_a_to_rgba(yuv_palette, alpha, sub_header->rects[0].rgba_palette, 256);
 343                 } else {
 344                     sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
 345                     sub_header->rects[0].nb_colors = 4;
 346                     guess_palette(sub_header->rects[0].rgba_palette,
 347                                   colormap, alpha, 0xffff00);
 348                 }
 349                 sub_header->rects[0].x = x1;
 350                 sub_header->rects[0].y = y1;
 351                 sub_header->rects[0].w = w;
 352                 sub_header->rects[0].h = h;
 353                 sub_header->rects[0].linesize = w;
 354             }
 355         }
 356         if (next_cmd_pos == cmd_pos)
 357             break;
 358         cmd_pos = next_cmd_pos;
 359     }
 360     if (sub_header->num_rects > 0)
 361         return is_menu;
 362  fail:
 363     if (sub_header->rects != NULL) {
 364         for (i = 0; i < sub_header->num_rects; i++) {
 365             av_free(sub_header->rects[i].bitmap);
 366             av_free(sub_header->rects[i].rgba_palette);
 367         }
 368         av_freep(&sub_header->rects);
 369         sub_header->num_rects = 0;
 370     }
 371     return -1;
 372 }
 373
 374 static int is_transp(const uint8_t *buf, int pitch, int n,
 375                      const uint8_t *transp_color)
 376 {
 377     int i;
 378     for(i = 0; i < n; i++) {
 379         if (!transp_color[*buf])
 380             return 0;
 381         buf += pitch;
 382     }
 383     return 1;
 384 }
 385
 386 /* return 0 if empty rectangle, 1 if non empty */
 387 static int find_smallest_bounding_rectangle(AVSubtitle *s)
 388 {
 389     uint8_t transp_color[256];
 390     int y1, y2, x1, x2, y, w, h, i;
 391     uint8_t *bitmap;
 392
 393     if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
 394         return 0;
 395
 396     memset(transp_color, 0, 256);
 397     for(i = 0; i < s->rects[0].nb_colors; i++) {
 398         if ((s->rects[0].rgba_palette[i] >> 24) == 0)
 399             transp_color[i] = 1;
 400     }
 401     y1 = 0;
 402     while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
 403                                   1, s->rects[0].w, transp_color))
 404         y1++;
 405     if (y1 == s->rects[0].h) {
 406         av_freep(&s->rects[0].bitmap);
 407         s->rects[0].w = s->rects[0].h = 0;
 408         return 0;
 409     }
 410
 411     y2 = s->rects[0].h - 1;
 412     while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
 413                                s->rects[0].w, transp_color))
 414         y2--;
 415     x1 = 0;
 416     while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
 417                                         s->rects[0].h, transp_color))
 418         x1++;
 419     x2 = s->rects[0].w - 1;
 420     while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
 421                                   transp_color))
 422         x2--;
 423     w = x2 - x1 + 1;
 424     h = y2 - y1 + 1;
 425     bitmap = av_malloc(w * h);
 426     if (!bitmap)
 427         return 1;
 428     for(y = 0; y < h; y++) {
 429         memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
 430     }
 431     av_freep(&s->rects[0].bitmap);
 432     s->rects[0].bitmap = bitmap;
 433     s->rects[0].linesize = w;
 434     s->rects[0].w = w;
 435     s->rects[0].h = h;
 436     s->rects[0].x += x1;
 437     s->rects[0].y += y1;
 438     return 1;
 439 }
 440
 441 #ifdef DEBUG
 442 #undef fprintf
 443 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
 444                      uint32_t *rgba_palette)
 445 {
 446     int x, y, v;
 447     FILE *f;
 448
 449     f = fopen(filename, "w");
 450     if (!f) {
 451         perror(filename);
 452         exit(1);
 453     }
 454     fprintf(f, "P6\n"
 455             "%d %d\n"
 456             "%d\n",
 457             w, h, 255);
 458     for(y = 0; y < h; y++) {
 459         for(x = 0; x < w; x++) {
 460             v = rgba_palette[bitmap[y * w + x]];
 461             putc((v >> 16) & 0xff, f);
 462             putc((v >> 8) & 0xff, f);
 463             putc((v >> 0) & 0xff, f);
 464         }
 465     }
 466     fclose(f);
 467 }
 468 #endif
 469
 470 static int dvdsub_decode(AVCodecContext *avctx,
 471                          void *data, int *data_size,
 472                          const uint8_t *buf, int buf_size)
 473 {
 474     AVSubtitle *sub = (void *)data;
 475     int is_menu;
 476
 477     is_menu = decode_dvd_subtitles(sub, buf, buf_size);
 478
 479     if (is_menu < 0) {
 480     no_subtitle:
 481         *data_size = 0;
 482
 483         return buf_size;
 484     }
 485     if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
 486         goto no_subtitle;
 487
 488 #if defined(DEBUG)
 489     av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
 490            sub->start_display_time,
 491            sub->end_display_time);
 492     ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
 493              sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
 494 #endif
 495
 496     *data_size = 1;
 497     return buf_size;
 498 }
 499
 500 AVCodec dvdsub_decoder = {
 501     "dvdsub",
 502     CODEC_TYPE_SUBTITLE,
 503     CODEC_ID_DVD_SUBTITLE,
 504     0,
 505     NULL,
 506     NULL,
 507     NULL,
 508     dvdsub_decode,
 509     .long_name = "DVD subtitles",
 510 };