extern/ffmpeg/libavcodec/dvdsub.c

   1 /*
   2  * DVD subtitle decoding for ffmpeg
   3  * Copyright (c) 2005 Fabrice Bellard.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19 #include "avcodec.h"
  20
  21 //#define DEBUG
  22
  23 typedef struct DVDSubContext {
  24 } DVDSubContext;
  25
  26 static int dvdsub_init_decoder(AVCodecContext *avctx)
  27 {
  28     return 0;
  29 }
  30
  31 static uint16_t getbe16(const uint8_t *p)
  32 {
  33     return (p[0] << 8) | p[1];
  34 }
  35
  36 static int get_nibble(const uint8_t *buf, int nibble_offset)
  37 {
  38     return (buf[nibble_offset >> 1] >> ((1 - (nibble_offset & 1)) << 2)) & 0xf;
  39 }
  40
  41 static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
  42                       const uint8_t *buf, int nibble_offset, int buf_size)
  43 {
  44     unsigned int v;
  45     int x, y, len, color, nibble_end;
  46     uint8_t *d;
  47
  48     nibble_end = buf_size * 2;
  49     x = 0;
  50     y = 0;
  51     d = bitmap;
  52     for(;;) {
  53         if (nibble_offset >= nibble_end)
  54             return -1;
  55         v = get_nibble(buf, nibble_offset++);
  56         if (v < 0x4) {
  57             v = (v << 4) | get_nibble(buf, nibble_offset++);
  58             if (v < 0x10) {
  59                 v = (v << 4) | get_nibble(buf, nibble_offset++);
  60                 if (v < 0x040) {
  61                     v = (v << 4) | get_nibble(buf, nibble_offset++);
  62                     if (v < 4) {
  63                         v |= (w - x) << 2;
  64                     }
  65                 }
  66             }
  67         }
  68         len = v >> 2;
  69         if (len > (w - x))
  70             len = (w - x);
  71         color = v & 0x03;
  72         memset(d + x, color, len);
  73         x += len;
  74         if (x >= w) {
  75             y++;
  76             if (y >= h)
  77                 break;
  78             d += linesize;
  79             x = 0;
  80             /* byte align */
  81             nibble_offset += (nibble_offset & 1);
  82         }
  83     }
  84     return 0;
  85 }
  86
  87 static void guess_palette(uint32_t *rgba_palette,
  88                           uint8_t *palette,
  89                           uint8_t *alpha,
  90                           uint32_t subtitle_color)
  91 {
  92     uint8_t color_used[16];
  93     int nb_opaque_colors, i, level, j, r, g, b;
  94
  95     for(i = 0; i < 4; i++)
  96         rgba_palette[i] = 0;
  97
  98     memset(color_used, 0, 16);
  99     nb_opaque_colors = 0;
 100     for(i = 0; i < 4; i++) {
 101         if (alpha[i] != 0 && !color_used[palette[i]]) {
 102             color_used[palette[i]] = 1;
 103             nb_opaque_colors++;
 104         }
 105     }
 106
 107     if (nb_opaque_colors == 0)
 108         return;
 109
 110     j = nb_opaque_colors;
 111     memset(color_used, 0, 16);
 112     for(i = 0; i < 4; i++) {
 113         if (alpha[i] != 0) {
 114             if (!color_used[palette[i]])  {
 115                 level = (0xff * j) / nb_opaque_colors;
 116                 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
 117                 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
 118                 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
 119                 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
 120                 color_used[palette[i]] = (i + 1);
 121                 j--;
 122             } else {
 123                 rgba_palette[i] = (rgba_palette[color_used[palette[i]] - 1] & 0x00ffffff) |
 124                                     ((alpha[i] * 17) << 24);
 125             }
 126         }
 127     }
 128 }
 129
 130 static int decode_dvd_subtitles(AVSubtitle *sub_header,
 131                                 const uint8_t *buf, int buf_size)
 132 {
 133     int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
 134     uint8_t palette[4], alpha[4];
 135     int date;
 136     int i;
 137     int is_menu = 0;
 138
 139     if (buf_size < 4)
 140         return -1;
 141     sub_header->rects = NULL;
 142     sub_header->num_rects = 0;
 143     sub_header->start_display_time = 0;
 144     sub_header->end_display_time = 0;
 145
 146     cmd_pos = getbe16(buf + 2);
 147     while ((cmd_pos + 4) < buf_size) {
 148         date = getbe16(buf + cmd_pos);
 149         next_cmd_pos = getbe16(buf + cmd_pos + 2);
 150 #ifdef DEBUG
 151         av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
 152                cmd_pos, next_cmd_pos, date);
 153 #endif
 154         pos = cmd_pos + 4;
 155         offset1 = -1;
 156         offset2 = -1;
 157         x1 = y1 = x2 = y2 = 0;
 158         while (pos < buf_size) {
 159             cmd = buf[pos++];
 160 #ifdef DEBUG
 161             av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
 162 #endif
 163             switch(cmd) {
 164             case 0x00:
 165                 /* menu subpicture */
 166                 is_menu = 1;
 167                 break;
 168             case 0x01:
 169                 /* set start date */
 170                 sub_header->start_display_time = (date << 10) / 90;
 171                 break;
 172             case 0x02:
 173                 /* set end date */
 174                 sub_header->end_display_time = (date << 10) / 90;
 175                 break;
 176             case 0x03:
 177                 /* set palette */
 178                 if ((buf_size - pos) < 2)
 179                     goto fail;
 180                 palette[3] = buf[pos] >> 4;
 181                 palette[2] = buf[pos] & 0x0f;
 182                 palette[1] = buf[pos + 1] >> 4;
 183                 palette[0] = buf[pos + 1] & 0x0f;
 184                 pos += 2;
 185                 break;
 186             case 0x04:
 187                 /* set alpha */
 188                 if ((buf_size - pos) < 2)
 189                     goto fail;
 190                 alpha[3] = buf[pos] >> 4;
 191                 alpha[2] = buf[pos] & 0x0f;
 192                 alpha[1] = buf[pos + 1] >> 4;
 193                 alpha[0] = buf[pos + 1] & 0x0f;
 194                 pos += 2;
 195 #ifdef DEBUG
 196             av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
 197 #endif
 198                 break;
 199             case 0x05:
 200                 if ((buf_size - pos) < 6)
 201                     goto fail;
 202                 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
 203                 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
 204                 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
 205                 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
 206 #ifdef DEBUG
 207                 av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
 208                        x1, x2, y1, y2);
 209 #endif
 210                 pos += 6;
 211                 break;
 212             case 0x06:
 213                 if ((buf_size - pos) < 4)
 214                     goto fail;
 215                 offset1 = getbe16(buf + pos);
 216                 offset2 = getbe16(buf + pos + 2);
 217 #ifdef DEBUG
 218                 av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
 219 #endif
 220                 pos += 4;
 221                 break;
 222             case 0xff:
 223             default:
 224                 goto the_end;
 225             }
 226         }
 227     the_end:
 228         if (offset1 >= 0) {
 229             int w, h;
 230             uint8_t *bitmap;
 231
 232             /* decode the bitmap */
 233             w = x2 - x1 + 1;
 234             if (w < 0)
 235                 w = 0;
 236             h = y2 - y1;
 237             if (h < 0)
 238                 h = 0;
 239             if (w > 0 && h > 0) {
 240                 if (sub_header->rects != NULL) {
 241                     for (i = 0; i < sub_header->num_rects; i++) {
 242                         av_free(sub_header->rects[i].bitmap);
 243                         av_free(sub_header->rects[i].rgba_palette);
 244                     }
 245                     av_freep(&sub_header->rects);
 246                     sub_header->num_rects = 0;
 247                 }
 248
 249                 bitmap = av_malloc(w * h);
 250                 sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
 251                 sub_header->num_rects = 1;
 252                 sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
 253                 decode_rle(bitmap, w * 2, w, h / 2,
 254                            buf, offset1 * 2, buf_size);
 255                 decode_rle(bitmap + w, w * 2, w, h / 2,
 256                            buf, offset2 * 2, buf_size);
 257                 guess_palette(sub_header->rects[0].rgba_palette,
 258                               palette, alpha, 0xffff00);
 259                 sub_header->rects[0].x = x1;
 260                 sub_header->rects[0].y = y1;
 261                 sub_header->rects[0].w = w;
 262                 sub_header->rects[0].h = h;
 263                 sub_header->rects[0].nb_colors = 4;
 264                 sub_header->rects[0].linesize = w;
 265                 sub_header->rects[0].bitmap = bitmap;
 266             }
 267         }
 268         if (next_cmd_pos == cmd_pos)
 269             break;
 270         cmd_pos = next_cmd_pos;
 271     }
 272     if (sub_header->num_rects > 0)
 273         return is_menu;
 274  fail:
 275     return -1;
 276 }
 277
 278 static int is_transp(const uint8_t *buf, int pitch, int n,
 279                      const uint8_t *transp_color)
 280 {
 281     int i;
 282     for(i = 0; i < n; i++) {
 283         if (!transp_color[*buf])
 284             return 0;
 285         buf += pitch;
 286     }
 287     return 1;
 288 }
 289
 290 /* return 0 if empty rectangle, 1 if non empty */
 291 static int find_smallest_bounding_rectangle(AVSubtitle *s)
 292 {
 293     uint8_t transp_color[256];
 294     int y1, y2, x1, x2, y, w, h, i;
 295     uint8_t *bitmap;
 296
 297     if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
 298         return 0;
 299
 300     memset(transp_color, 0, 256);
 301     for(i = 0; i < s->rects[0].nb_colors; i++) {
 302         if ((s->rects[0].rgba_palette[i] >> 24) == 0)
 303             transp_color[i] = 1;
 304     }
 305     y1 = 0;
 306     while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
 307                                   1, s->rects[0].w, transp_color))
 308         y1++;
 309     if (y1 == s->rects[0].h) {
 310         av_freep(&s->rects[0].bitmap);
 311         s->rects[0].w = s->rects[0].h = 0;
 312         return 0;
 313     }
 314
 315     y2 = s->rects[0].h - 1;
 316     while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
 317                                s->rects[0].w, transp_color))
 318         y2--;
 319     x1 = 0;
 320     while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
 321                                         s->rects[0].h, transp_color))
 322         x1++;
 323     x2 = s->rects[0].w - 1;
 324     while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
 325                                   transp_color))
 326         x2--;
 327     w = x2 - x1 + 1;
 328     h = y2 - y1 + 1;
 329     bitmap = av_malloc(w * h);
 330     if (!bitmap)
 331         return 1;
 332     for(y = 0; y < h; y++) {
 333         memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
 334     }
 335     av_freep(&s->rects[0].bitmap);
 336     s->rects[0].bitmap = bitmap;
 337     s->rects[0].linesize = w;
 338     s->rects[0].w = w;
 339     s->rects[0].h = h;
 340     s->rects[0].x += x1;
 341     s->rects[0].y += y1;
 342     return 1;
 343 }
 344
 345 static int dvdsub_close_decoder(AVCodecContext *avctx)
 346 {
 347     return 0;
 348 }
 349
 350 #ifdef DEBUG
 351 #undef fprintf
 352 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
 353                      uint32_t *rgba_palette)
 354 {
 355     int x, y, v;
 356     FILE *f;
 357
 358     f = fopen(filename, "w");
 359     if (!f) {
 360         perror(filename);
 361         exit(1);
 362     }
 363     fprintf(f, "P6\n"
 364             "%d %d\n"
 365             "%d\n",
 366             w, h, 255);
 367     for(y = 0; y < h; y++) {
 368         for(x = 0; x < w; x++) {
 369             v = rgba_palette[bitmap[y * w + x]];
 370             putc((v >> 16) & 0xff, f);
 371             putc((v >> 8) & 0xff, f);
 372             putc((v >> 0) & 0xff, f);
 373         }
 374     }
 375     fclose(f);
 376 }
 377 #endif
 378
 379 static int dvdsub_decode(AVCodecContext *avctx,
 380                          void *data, int *data_size,
 381                          uint8_t *buf, int buf_size)
 382 {
 383     AVSubtitle *sub = (void *)data;
 384     int is_menu;
 385
 386     is_menu = decode_dvd_subtitles(sub, buf, buf_size);
 387
 388     if (is_menu < 0) {
 389     no_subtitle:
 390         *data_size = 0;
 391
 392         return buf_size;
 393     }
 394     if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
 395         goto no_subtitle;
 396
 397 #if defined(DEBUG)
 398     av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
 399            sub->start_display_time,
 400            sub->end_display_time);
 401     ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
 402              sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
 403 #endif
 404
 405     *data_size = 1;
 406     return buf_size;
 407 }
 408
 409 AVCodec dvdsub_decoder = {
 410     "dvdsub",
 411     CODEC_TYPE_SUBTITLE,
 412     CODEC_ID_DVD_SUBTITLE,
 413     sizeof(DVDSubContext),
 414     dvdsub_init_decoder,
 415     NULL,
 416     dvdsub_close_decoder,
 417     dvdsub_decode,
 418 };
 419
 420 /* parser definition */
 421 typedef struct DVDSubParseContext {
 422     uint8_t *packet;
 423     int packet_len;
 424     int packet_index;
 425 } DVDSubParseContext;
 426
 427 static int dvdsub_parse_init(AVCodecParserContext *s)
 428 {
 429     return 0;
 430 }
 431
 432 static int dvdsub_parse(AVCodecParserContext *s,
 433                         AVCodecContext *avctx,
 434                         uint8_t **poutbuf, int *poutbuf_size,
 435                         const uint8_t *buf, int buf_size)
 436 {
 437     DVDSubParseContext *pc = s->priv_data;
 438
 439     if (pc->packet_index == 0) {
 440         if (buf_size < 2)
 441             return 0;
 442         pc->packet_len = (buf[0] << 8) | buf[1];
 443         av_freep(&pc->packet);
 444         pc->packet = av_malloc(pc->packet_len);
 445     }
 446     if (pc->packet) {
 447         if (pc->packet_index + buf_size <= pc->packet_len) {
 448             memcpy(pc->packet + pc->packet_index, buf, buf_size);
 449             pc->packet_index += buf_size;
 450             if (pc->packet_index >= pc->packet_len) {
 451                 *poutbuf = pc->packet;
 452                 *poutbuf_size = pc->packet_len;
 453                 pc->packet_index = 0;
 454                 return buf_size;
 455             }
 456         } else {
 457             /* erroneous size */
 458             pc->packet_index = 0;
 459         }
 460     }
 461     *poutbuf = NULL;
 462     *poutbuf_size = 0;
 463     return buf_size;
 464 }
 465
 466 static void dvdsub_parse_close(AVCodecParserContext *s)
 467 {
 468     DVDSubParseContext *pc = s->priv_data;
 469     av_freep(&pc->packet);
 470 }
 471
 472 AVCodecParser dvdsub_parser = {
 473     { CODEC_ID_DVD_SUBTITLE },
 474     sizeof(DVDSubParseContext),
 475     dvdsub_parse_init,
 476     dvdsub_parse,
 477     dvdsub_parse_close,
 478 };