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     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         dprintf(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             dprintf(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             dprintf(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                 dprintf(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                 dprintf(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                 dprintf(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                 dprintf(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
 359 static 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 */
 372 static 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
 430 static 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
 457 static 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 = (void *)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     dprintf(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
 489 AVCodec dvdsub_decoder = {
 490     "dvdsub",
 491     CODEC_TYPE_SUBTITLE,
 492     CODEC_ID_DVD_SUBTITLE,
 493     0,
 494     NULL,
 495     NULL,
 496     NULL,
 497     dvdsub_decode,
 498     .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
 499 };