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 #include "avcodec.h"
  22 #include "get_bits.h"
  23 #include "dsputil.h"
  24 #include "libavutil/colorspace.h"
  25 #include "libavutil/imgutils.h"
  26 #include "libavutil/avstring.h"
  27
  28 //#define DEBUG
  29
  30 typedef struct DVDSubContext {
  31     uint32_t palette[16];
  32     int      has_palette;
  33 } DVDSubContext;
  34
  35 static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
  36 {
  37     uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
  38     uint8_t r, g, b;
  39     int i, y, cb, cr;
  40     int r_add, g_add, b_add;
  41
  42     for (i = num_values; i > 0; i--) {
  43         y = *ycbcr++;
  44         cr = *ycbcr++;
  45         cb = *ycbcr++;
  46         YUV_TO_RGB1_CCIR(cb, cr);
  47         YUV_TO_RGB2_CCIR(r, g, b, y);
  48         *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;
  49     }
  50 }
  51
  52 static int decode_run_2bit(GetBitContext *gb, int *color)
  53 {
  54     unsigned int v, t;
  55
  56     v = 0;
  57     for (t = 1; v < t && t <= 0x40; t <<= 2)
  58         v = (v << 4) | get_bits(gb, 4);
  59     *color = v & 3;
  60     if (v < 4) { /* Code for fill rest of line */
  61         return INT_MAX;
  62     }
  63     return v >> 2;
  64 }
  65
  66 static int decode_run_8bit(GetBitContext *gb, int *color)
  67 {
  68     int len;
  69     int has_run = get_bits1(gb);
  70     if (get_bits1(gb))
  71         *color = get_bits(gb, 8);
  72     else
  73         *color = get_bits(gb, 2);
  74     if (has_run) {
  75         if (get_bits1(gb)) {
  76             len = get_bits(gb, 7);
  77             if (len == 0)
  78                 len = INT_MAX;
  79             else
  80                 len += 9;
  81         } else
  82             len = get_bits(gb, 3) + 2;
  83     } else
  84         len = 1;
  85     return len;
  86 }
  87
  88 static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
  89                       const uint8_t *buf, int start, int buf_size, int is_8bit)
  90 {
  91     GetBitContext gb;
  92     int bit_len;
  93     int x, y, len, color;
  94     uint8_t *d;
  95
  96     bit_len = (buf_size - start) * 8;
  97     init_get_bits(&gb, buf + start, bit_len);
  98
  99     x = 0;
 100     y = 0;
 101     d = bitmap;
 102     for(;;) {
 103         if (get_bits_count(&gb) > bit_len)
 104             return -1;
 105         if (is_8bit)
 106             len = decode_run_8bit(&gb, &color);
 107         else
 108             len = decode_run_2bit(&gb, &color);
 109         len = FFMIN(len, w - x);
 110         memset(d + x, color, len);
 111         x += len;
 112         if (x >= w) {
 113             y++;
 114             if (y >= h)
 115                 break;
 116             d += linesize;
 117             x = 0;
 118             /* byte align */
 119             align_get_bits(&gb);
 120         }
 121     }
 122     return 0;
 123 }
 124
 125 static void guess_palette(DVDSubContext* ctx,
 126                           uint32_t *rgba_palette,
 127                           uint8_t *colormap,
 128                           uint8_t *alpha,
 129                           uint32_t subtitle_color)
 130 {
 131     uint8_t color_used[16] = { 0 };
 132     int nb_opaque_colors, i, level, j, r, g, b;
 133
 134     if (ctx->has_palette) {
 135         for (i = 0; i < 4; i++)
 136             rgba_palette[i] = (ctx->palette[colormap[i]] & 0x00ffffff)
 137                               | ((alpha[i] * 17) << 24);
 138         return;
 139     }
 140
 141     for(i = 0; i < 4; i++)
 142         rgba_palette[i] = 0;
 143
 144     nb_opaque_colors = 0;
 145     for(i = 0; i < 4; i++) {
 146         if (alpha[i] != 0 && !color_used[colormap[i]]) {
 147             color_used[colormap[i]] = 1;
 148             nb_opaque_colors++;
 149         }
 150     }
 151
 152     if (nb_opaque_colors == 0)
 153         return;
 154
 155     j = nb_opaque_colors;
 156     memset(color_used, 0, 16);
 157     for(i = 0; i < 4; i++) {
 158         if (alpha[i] != 0) {
 159             if (!color_used[colormap[i]])  {
 160                 level = (0xff * j) / nb_opaque_colors;
 161                 r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
 162                 g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
 163                 b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
 164                 rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
 165                 color_used[colormap[i]] = (i + 1);
 166                 j--;
 167             } else {
 168                 rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
 169                                     ((alpha[i] * 17) << 24);
 170             }
 171         }
 172     }
 173 }
 174
 175 #define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
 176
 177 static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,
 178                                 const uint8_t *buf, int buf_size)
 179 {
 180     int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
 181     int big_offsets, offset_size, is_8bit = 0;
 182     const uint8_t *yuv_palette = 0;
 183     uint8_t colormap[4] = { 0 }, alpha[256] = { 0 };
 184     int date;
 185     int i;
 186     int is_menu = 0;
 187
 188     if (buf_size < 10)
 189         return -1;
 190     memset(sub_header, 0, sizeof(*sub_header));
 191
 192     if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
 193         big_offsets = 1;
 194         offset_size = 4;
 195         cmd_pos = 6;
 196     } else {
 197         big_offsets = 0;
 198         offset_size = 2;
 199         cmd_pos = 2;
 200     }
 201
 202     cmd_pos = READ_OFFSET(buf + cmd_pos);
 203
 204     while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) {
 205         date = AV_RB16(buf + cmd_pos);
 206         next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
 207         av_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",
 208                 cmd_pos, next_cmd_pos, date);
 209         pos = cmd_pos + 2 + offset_size;
 210         offset1 = -1;
 211         offset2 = -1;
 212         x1 = y1 = x2 = y2 = 0;
 213         while (pos < buf_size) {
 214             cmd = buf[pos++];
 215             av_dlog(NULL, "cmd=%02x\n", cmd);
 216             switch(cmd) {
 217             case 0x00:
 218                 /* menu subpicture */
 219                 is_menu = 1;
 220                 break;
 221             case 0x01:
 222                 /* set start date */
 223                 sub_header->start_display_time = (date << 10) / 90;
 224                 break;
 225             case 0x02:
 226                 /* set end date */
 227                 sub_header->end_display_time = (date << 10) / 90;
 228                 break;
 229             case 0x03:
 230                 /* set colormap */
 231                 if ((buf_size - pos) < 2)
 232                     goto fail;
 233                 colormap[3] = buf[pos] >> 4;
 234                 colormap[2] = buf[pos] & 0x0f;
 235                 colormap[1] = buf[pos + 1] >> 4;
 236                 colormap[0] = buf[pos + 1] & 0x0f;
 237                 pos += 2;
 238                 break;
 239             case 0x04:
 240                 /* set alpha */
 241                 if ((buf_size - pos) < 2)
 242                     goto fail;
 243                 alpha[3] = buf[pos] >> 4;
 244                 alpha[2] = buf[pos] & 0x0f;
 245                 alpha[1] = buf[pos + 1] >> 4;
 246                 alpha[0] = buf[pos + 1] & 0x0f;
 247                 pos += 2;
 248             av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
 249                 break;
 250             case 0x05:
 251             case 0x85:
 252                 if ((buf_size - pos) < 6)
 253                     goto fail;
 254                 x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
 255                 x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
 256                 y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
 257                 y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
 258                 if (cmd & 0x80)
 259                     is_8bit = 1;
 260                 av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);
 261                 pos += 6;
 262                 break;
 263             case 0x06:
 264                 if ((buf_size - pos) < 4)
 265                     goto fail;
 266                 offset1 = AV_RB16(buf + pos);
 267                 offset2 = AV_RB16(buf + pos + 2);
 268                 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
 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                 av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
 277                 pos += 8;
 278                 break;
 279
 280             case 0x83:
 281                 /* HD set palette */
 282                 if ((buf_size - pos) < 768)
 283                     goto fail;
 284                 yuv_palette = buf + pos;
 285                 pos += 768;
 286                 break;
 287             case 0x84:
 288                 /* HD set contrast (alpha) */
 289                 if ((buf_size - pos) < 256)
 290                     goto fail;
 291                 for (i = 0; i < 256; i++)
 292                     alpha[i] = 0xFF - buf[pos+i];
 293                 pos += 256;
 294                 break;
 295
 296             case 0xff:
 297                 goto the_end;
 298             default:
 299                 av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);
 300                 goto the_end;
 301             }
 302         }
 303     the_end:
 304         if (offset1 >= 0) {
 305             int w, h;
 306             uint8_t *bitmap;
 307
 308             /* decode the bitmap */
 309             w = x2 - x1 + 1;
 310             if (w < 0)
 311                 w = 0;
 312             h = y2 - y1;
 313             if (h < 0)
 314                 h = 0;
 315             if (w > 0 && h > 0) {
 316                 if (sub_header->rects != NULL) {
 317                     for (i = 0; i < sub_header->num_rects; i++) {
 318                         av_freep(&sub_header->rects[i]->pict.data[0]);
 319                         av_freep(&sub_header->rects[i]->pict.data[1]);
 320                         av_freep(&sub_header->rects[i]);
 321                     }
 322                     av_freep(&sub_header->rects);
 323                     sub_header->num_rects = 0;
 324                 }
 325
 326                 bitmap = av_malloc(w * h);
 327                 sub_header->rects = av_mallocz(sizeof(*sub_header->rects));
 328                 sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));
 329                 sub_header->num_rects = 1;
 330                 sub_header->rects[0]->pict.data[0] = bitmap;
 331                 decode_rle(bitmap, w * 2, w, (h + 1) / 2,
 332                            buf, offset1, buf_size, is_8bit);
 333                 decode_rle(bitmap + w, w * 2, w, h / 2,
 334                            buf, offset2, buf_size, is_8bit);
 335                 sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
 336                 if (is_8bit) {
 337                     if (yuv_palette == 0)
 338                         goto fail;
 339                     sub_header->rects[0]->nb_colors = 256;
 340                     yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);
 341                 } else {
 342                     sub_header->rects[0]->nb_colors = 4;
 343                     guess_palette(ctx,
 344                                   (uint32_t*)sub_header->rects[0]->pict.data[1],
 345                                   colormap, alpha, 0xffff00);
 346                 }
 347                 sub_header->rects[0]->x = x1;
 348                 sub_header->rects[0]->y = y1;
 349                 sub_header->rects[0]->w = w;
 350                 sub_header->rects[0]->h = h;
 351                 sub_header->rects[0]->type = SUBTITLE_BITMAP;
 352                 sub_header->rects[0]->pict.linesize[0] = w;
 353             }
 354         }
 355         if (next_cmd_pos == cmd_pos)
 356             break;
 357         cmd_pos = next_cmd_pos;
 358     }
 359     if (sub_header->num_rects > 0)
 360         return is_menu;
 361  fail:
 362     if (sub_header->rects != NULL) {
 363         for (i = 0; i < sub_header->num_rects; i++) {
 364             av_freep(&sub_header->rects[i]->pict.data[0]);
 365             av_freep(&sub_header->rects[i]->pict.data[1]);
 366             av_freep(&sub_header->rects[i]);
 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] = { 0 };
 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     for(i = 0; i < s->rects[0]->nb_colors; i++) {
 397         if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)
 398             transp_color[i] = 1;
 399     }
 400     y1 = 0;
 401     while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],
 402                                   1, s->rects[0]->w, transp_color))
 403         y1++;
 404     if (y1 == s->rects[0]->h) {
 405         av_freep(&s->rects[0]->pict.data[0]);
 406         s->rects[0]->w = s->rects[0]->h = 0;
 407         return 0;
 408     }
 409
 410     y2 = s->rects[0]->h - 1;
 411     while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,
 412                                s->rects[0]->w, transp_color))
 413         y2--;
 414     x1 = 0;
 415     while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],
 416                                         s->rects[0]->h, transp_color))
 417         x1++;
 418     x2 = s->rects[0]->w - 1;
 419     while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,
 420                                   transp_color))
 421         x2--;
 422     w = x2 - x1 + 1;
 423     h = y2 - y1 + 1;
 424     bitmap = av_malloc(w * h);
 425     if (!bitmap)
 426         return 1;
 427     for(y = 0; y < h; y++) {
 428         memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);
 429     }
 430     av_freep(&s->rects[0]->pict.data[0]);
 431     s->rects[0]->pict.data[0] = bitmap;
 432     s->rects[0]->pict.linesize[0] = w;
 433     s->rects[0]->w = w;
 434     s->rects[0]->h = h;
 435     s->rects[0]->x += x1;
 436     s->rects[0]->y += y1;
 437     return 1;
 438 }
 439
 440 #ifdef DEBUG
 441 #undef fprintf
 442 #undef perror
 443 #undef exit
 444 static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
 445                      uint32_t *rgba_palette)
 446 {
 447     int x, y, v;
 448     FILE *f;
 449
 450     f = fopen(filename, "w");
 451     if (!f) {
 452         perror(filename);
 453         exit(1);
 454     }
 455     fprintf(f, "P6\n"
 456             "%d %d\n"
 457             "%d\n",
 458             w, h, 255);
 459     for(y = 0; y < h; y++) {
 460         for(x = 0; x < w; x++) {
 461             v = rgba_palette[bitmap[y * w + x]];
 462             putc((v >> 16) & 0xff, f);
 463             putc((v >> 8) & 0xff, f);
 464             putc((v >> 0) & 0xff, f);
 465         }
 466     }
 467     fclose(f);
 468 }
 469 #endif
 470
 471 static int dvdsub_decode(AVCodecContext *avctx,
 472                          void *data, int *data_size,
 473                          AVPacket *avpkt)
 474 {
 475     DVDSubContext *ctx = avctx->priv_data;
 476     const uint8_t *buf = avpkt->data;
 477     int buf_size = avpkt->size;
 478     AVSubtitle *sub = data;
 479     int is_menu;
 480
 481     is_menu = decode_dvd_subtitles(ctx, sub, buf, buf_size);
 482
 483     if (is_menu < 0) {
 484     no_subtitle:
 485         *data_size = 0;
 486
 487         return buf_size;
 488     }
 489     if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
 490         goto no_subtitle;
 491
 492 #if defined(DEBUG)
 493     av_dlog(NULL, "start=%d ms end =%d ms\n",
 494             sub->start_display_time,
 495             sub->end_display_time);
 496     ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0],
 497              sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]);
 498 #endif
 499
 500     *data_size = 1;
 501     return buf_size;
 502 }
 503
 504 static int dvdsub_init(AVCodecContext *avctx)
 505 {
 506     DVDSubContext *ctx = avctx->priv_data;
 507     char *data, *cur;
 508
 509     if (!avctx->extradata || !avctx->extradata_size)
 510         return 0;
 511
 512     data = av_malloc(avctx->extradata_size + 1);
 513     if (!data)
 514         return AVERROR(ENOMEM);
 515     memcpy(data, avctx->extradata, avctx->extradata_size);
 516     data[avctx->extradata_size] = '\0';
 517     cur = data;
 518
 519     while (*cur) {
 520         if (strncmp("palette:", cur, 8) == 0) {
 521             int i;
 522             char *p = cur + 8;
 523             ctx->has_palette = 1;
 524             for (i = 0; i < 16; i++) {
 525                 ctx->palette[i] = strtoul(p, &p, 16);
 526                 while (*p == ',' || av_isspace(*p))
 527                     p++;
 528             }
 529         } else if (!strncmp("size:", cur, 5)) {
 530             int w, h;
 531             if (sscanf(cur + 5, "%dx%d", &w, &h) == 2 &&
 532                 av_image_check_size(w, h, 0, avctx) >= 0)
 533                 avcodec_set_dimensions(avctx, w, h);
 534         }
 535         cur += strcspn(cur, "\n\r");
 536         cur += strspn(cur, "\n\r");
 537     }
 538     av_free(data);
 539     return 0;
 540 }
 541
 542 AVCodec ff_dvdsub_decoder = {
 543     .name           = "dvdsub",
 544     .type           = AVMEDIA_TYPE_SUBTITLE,
 545     .id             = AV_CODEC_ID_DVD_SUBTITLE,
 546     .priv_data_size = sizeof(DVDSubContext),
 547     .init           = dvdsub_init,
 548     .decode         = dvdsub_decode,
 549     .long_name      = NULL_IF_CONFIG_SMALL("DVD subtitles"),
 550 };