git.sesse.net Git - vlc/blob - modules/codec/spudec/parse.c

   1 /*****************************************************************************
   2  * parse.c: SPU parser
   3  *****************************************************************************
   4  * Copyright (C) 2000-2001, 2005, 2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Sam Hocevar <sam@zoy.org>
   8  *          Laurent Aimar <fenrir@via.ecp.fr>
   9  *          Gildas Bazin <gbazin@videolan.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29 #include <vlc/vlc.h>
  30 #include <vlc/vout.h>
  31 #include <vlc/decoder.h>
  32
  33 #include "spudec.h"
  34
  35 /*****************************************************************************
  36  * Local prototypes.
  37  *****************************************************************************/
  38 static int  ParseControlSeq( decoder_t *, subpicture_t *, subpicture_data_t *);
  39 static int  ParseRLE       ( decoder_t *, subpicture_t *, subpicture_data_t *);
  40 static void Render         ( decoder_t *, subpicture_t *, subpicture_data_t *);
  41
  42 /*****************************************************************************
  43  * AddNibble: read a nibble from a source packet and add it to our integer.
  44  *****************************************************************************/
  45 static inline unsigned int AddNibble( unsigned int i_code,
  46                                       uint8_t *p_src, unsigned int *pi_index )
  47 {
  48     if( *pi_index & 0x1 )
  49     {
  50         return( i_code << 4 | ( p_src[(*pi_index)++ >> 1] & 0xf ) );
  51     }
  52     else
  53     {
  54         return( i_code << 4 | p_src[(*pi_index)++ >> 1] >> 4 );
  55     }
  56 }
  57
  58 /*****************************************************************************
  59  * ParsePacket: parse an SPU packet and send it to the video output
  60  *****************************************************************************
  61  * This function parses the SPU packet and, if valid, sends it to the
  62  * video output.
  63  *****************************************************************************/
  64 subpicture_t * E_(ParsePacket)( decoder_t *p_dec )
  65 {
  66     decoder_sys_t *p_sys = p_dec->p_sys;
  67     subpicture_data_t *p_spu_data;
  68     subpicture_t *p_spu;
  69
  70     /* Allocate the subpicture internal data. */
  71     p_spu = p_dec->pf_spu_buffer_new( p_dec );
  72     if( !p_spu ) return NULL;
  73
  74     /* Rationale for the "p_spudec->i_rle_size * 4": we are going to
  75      * expand the RLE stuff so that we won't need to read nibbles later
  76      * on. This will speed things up a lot. Plus, we'll only need to do
  77      * this stupid interlacing stuff once. */
  78     p_spu_data = malloc( sizeof(subpicture_data_t) + 4 * p_sys->i_rle_size );
  79     p_spu_data->p_data = (uint8_t *)p_spu_data + sizeof(subpicture_data_t);
  80     p_spu_data->b_palette = VLC_FALSE;
  81     p_spu_data->b_auto_crop = VLC_FALSE;
  82     p_spu_data->i_y_top_offset = 0;
  83     p_spu_data->i_y_bottom_offset = 0;
  84
  85     p_spu_data->pi_alpha[0] = 0x00;
  86     p_spu_data->pi_alpha[1] = 0x0f;
  87     p_spu_data->pi_alpha[2] = 0x0f;
  88     p_spu_data->pi_alpha[3] = 0x0f;
  89
  90     /* Get display time now. If we do it later, we may miss the PTS. */
  91     p_spu_data->i_pts = p_sys->i_pts;
  92
  93     p_spu->i_original_picture_width =
  94         p_dec->fmt_in.subs.spu.i_original_frame_width;
  95     p_spu->i_original_picture_height =
  96         p_dec->fmt_in.subs.spu.i_original_frame_height;
  97
  98     /* Getting the control part */
  99     if( ParseControlSeq( p_dec, p_spu, p_spu_data ) )
 100     {
 101         /* There was a parse error, delete the subpicture */
 102         p_dec->pf_spu_buffer_del( p_dec, p_spu );
 103         return NULL;
 104     }
 105
 106     /* We try to display it */
 107     if( ParseRLE( p_dec, p_spu, p_spu_data ) )
 108     {
 109         /* There was a parse error, delete the subpicture */
 110         p_dec->pf_spu_buffer_del( p_dec, p_spu );
 111         return NULL;
 112     }
 113
 114 #ifdef DEBUG_SPUDEC
 115     msg_Dbg( p_dec, "total size: 0x%x, RLE offsets: 0x%x 0x%x",
 116              p_sys->i_spu_size,
 117              p_spu_data->pi_offset[0], p_spu_data->pi_offset[1] );
 118 #endif
 119
 120     Render( p_dec, p_spu, p_spu_data );
 121     free( p_spu_data );
 122
 123     return p_spu;
 124 }
 125
 126 /*****************************************************************************
 127  * ParseControlSeq: parse all SPU control sequences
 128  *****************************************************************************
 129  * This is the most important part in SPU decoding. We get dates, palette
 130  * information, coordinates, and so on. For more information on the
 131  * subtitles format, see http://sam.zoy.org/doc/dvd/subtitles/index.html
 132  *****************************************************************************/
 133 static int ParseControlSeq( decoder_t *p_dec, subpicture_t *p_spu,
 134                             subpicture_data_t *p_spu_data )
 135 {
 136     decoder_sys_t *p_sys = p_dec->p_sys;
 137
 138     /* Our current index in the SPU packet */
 139     unsigned int i_index = p_sys->i_rle_size + 4;
 140
 141     /* The next start-of-control-sequence index and the previous one */
 142     unsigned int i_next_seq = 0, i_cur_seq = 0;
 143
 144     /* Command and date */
 145     uint8_t i_command = SPU_CMD_END;
 146     mtime_t date = 0;
 147
 148     /* Initialize the structure */
 149     p_spu->i_start = p_spu->i_stop = 0;
 150     p_spu->b_ephemer = VLC_FALSE;
 151
 152     for( i_index = 4 + p_sys->i_rle_size; i_index < p_sys->i_spu_size ; )
 153     {
 154         /* If we just read a command sequence, read the next one;
 155          * otherwise, go on with the commands of the current sequence. */
 156         if( i_command == SPU_CMD_END )
 157         {
 158             if( i_index + 4 > p_sys->i_spu_size )
 159             {
 160                 msg_Err( p_dec, "overflow in SPU command sequence" );
 161                 return VLC_EGENERIC;
 162             }
 163
 164             /* Get the control sequence date */
 165             date = (mtime_t)GetWBE( &p_sys->buffer[i_index] ) * 11000;
 166             /* FIXME How to access i_rate
 167                     * p_spudec->bit_stream.p_pes->i_rate / DEFAULT_RATE;
 168             */
 169
 170             /* Next offset */
 171             i_cur_seq = i_index;
 172             i_next_seq = GetWBE( &p_sys->buffer[i_index+2] );
 173
 174             if( i_next_seq > p_sys->i_spu_size )
 175             {
 176                 msg_Err( p_dec, "overflow in SPU next command sequence" );
 177                 return VLC_EGENERIC;
 178             }
 179
 180             /* Skip what we just read */
 181             i_index += 4;
 182         }
 183
 184         i_command = p_sys->buffer[i_index];
 185
 186         switch( i_command )
 187         {
 188         case SPU_CMD_FORCE_DISPLAY: /* 00 (force displaying) */
 189             p_spu->i_start = p_spu_data->i_pts + date;
 190             p_spu->b_ephemer = VLC_TRUE;
 191             i_index += 1;
 192             break;
 193
 194         /* Convert the dates in seconds to PTS values */
 195         case SPU_CMD_START_DISPLAY: /* 01 (start displaying) */
 196             p_spu->i_start = p_spu_data->i_pts + date;
 197             i_index += 1;
 198             break;
 199
 200         case SPU_CMD_STOP_DISPLAY: /* 02 (stop displaying) */
 201             p_spu->i_stop = p_spu_data->i_pts + date;
 202             i_index += 1;
 203             break;
 204
 205         case SPU_CMD_SET_PALETTE:
 206
 207             /* 03xxxx (palette) */
 208             if( i_index + 3 > p_sys->i_spu_size )
 209             {
 210                 msg_Err( p_dec, "overflow in SPU command" );
 211                 return VLC_EGENERIC;
 212             }
 213
 214             if( p_dec->fmt_in.subs.spu.palette[0] == 0xBeeF )
 215             {
 216                 unsigned int idx[4];
 217                 int i;
 218
 219                 p_spu_data->b_palette = VLC_TRUE;
 220
 221                 idx[0] = (p_sys->buffer[i_index+1]>>4)&0x0f;
 222                 idx[1] = (p_sys->buffer[i_index+1])&0x0f;
 223                 idx[2] = (p_sys->buffer[i_index+2]>>4)&0x0f;
 224                 idx[3] = (p_sys->buffer[i_index+2])&0x0f;
 225
 226                 for( i = 0; i < 4 ; i++ )
 227                 {
 228                     uint32_t i_color = p_dec->fmt_in.subs.spu.palette[1+idx[i]];
 229
 230                     /* FIXME: this job should be done sooner */
 231                     p_spu_data->pi_yuv[3-i][0] = (i_color>>16) & 0xff;
 232                     p_spu_data->pi_yuv[3-i][1] = (i_color>>0) & 0xff;
 233                     p_spu_data->pi_yuv[3-i][2] = (i_color>>8) & 0xff;
 234                 }
 235             }
 236
 237             i_index += 3;
 238             break;
 239
 240         case SPU_CMD_SET_ALPHACHANNEL: /* 04xxxx (alpha channel) */
 241             if( i_index + 3 > p_sys->i_spu_size )
 242             {
 243                 msg_Err( p_dec, "overflow in SPU command" );
 244                 return VLC_EGENERIC;
 245             }
 246
 247             p_spu_data->pi_alpha[3] = (p_sys->buffer[i_index+1]>>4)&0x0f;
 248             p_spu_data->pi_alpha[2] = (p_sys->buffer[i_index+1])&0x0f;
 249             p_spu_data->pi_alpha[1] = (p_sys->buffer[i_index+2]>>4)&0x0f;
 250             p_spu_data->pi_alpha[0] = (p_sys->buffer[i_index+2])&0x0f;
 251
 252             i_index += 3;
 253             break;
 254
 255         case SPU_CMD_SET_COORDINATES: /* 05xxxyyyxxxyyy (coordinates) */
 256             if( i_index + 7 > p_sys->i_spu_size )
 257             {
 258                 msg_Err( p_dec, "overflow in SPU command" );
 259                 return VLC_EGENERIC;
 260             }
 261
 262             p_spu->i_x = (p_sys->buffer[i_index+1]<<4)|
 263                          ((p_sys->buffer[i_index+2]>>4)&0x0f);
 264             p_spu->i_width = (((p_sys->buffer[i_index+2]&0x0f)<<8)|
 265                               p_sys->buffer[i_index+3]) - p_spu->i_x + 1;
 266
 267             p_spu->i_y = (p_sys->buffer[i_index+4]<<4)|
 268                          ((p_sys->buffer[i_index+5]>>4)&0x0f);
 269             p_spu->i_height = (((p_sys->buffer[i_index+5]&0x0f)<<8)|
 270                               p_sys->buffer[i_index+6]) - p_spu->i_y + 1;
 271
 272             /* Auto crop fullscreen subtitles */
 273             if( p_spu->i_height > 250 )
 274                 p_spu_data->b_auto_crop = VLC_TRUE;
 275
 276             i_index += 7;
 277             break;
 278
 279         case SPU_CMD_SET_OFFSETS: /* 06xxxxyyyy (byte offsets) */
 280             if( i_index + 5 > p_sys->i_spu_size )
 281             {
 282                 msg_Err( p_dec, "overflow in SPU command" );
 283                 return VLC_EGENERIC;
 284             }
 285
 286             p_spu_data->pi_offset[0] = GetWBE(&p_sys->buffer[i_index+1]) - 4;
 287             p_spu_data->pi_offset[1] = GetWBE(&p_sys->buffer[i_index+3]) - 4;
 288             i_index += 5;
 289             break;
 290
 291         case SPU_CMD_END: /* ff (end) */
 292             i_index += 1;
 293             break;
 294
 295         default: /* xx (unknown command) */
 296             msg_Warn( p_dec, "unknown SPU command 0x%.2x", i_command );
 297             if( i_index + 1 < i_next_seq )
 298             {
 299                  /* There is at least one other command sequence */
 300                  if( p_sys->buffer[i_next_seq - 1] == SPU_CMD_END )
 301                  {
 302                      /* This is consistent. Skip to that command sequence. */
 303                      i_index = i_next_seq;
 304                  }
 305                  else
 306                  {
 307                      /* There were other commands. */
 308                      msg_Warn( p_dec, "cannot recover, dropping subtitle" );
 309                      return VLC_EGENERIC;
 310                  }
 311             }
 312             else
 313             {
 314                 /* We were in the last command sequence. Stop parsing by
 315                  * pretending we met an SPU_CMD_END command. */
 316                 i_command = SPU_CMD_END;
 317                 i_index++;
 318             }
 319         }
 320
 321         /* We need to check for quit commands here */
 322         if( p_dec->b_die )
 323         {
 324             return VLC_EGENERIC;
 325         }
 326
 327         if( i_command == SPU_CMD_END && i_index != i_next_seq )
 328         {
 329             break;
 330         }
 331     }
 332
 333     /* Check that the next sequence index matches the current one */
 334     if( i_next_seq != i_cur_seq )
 335     {
 336         msg_Err( p_dec, "index mismatch (0x%.4x != 0x%.4x)",
 337                  i_next_seq, i_cur_seq );
 338         return VLC_EGENERIC;
 339     }
 340
 341     if( i_index > p_sys->i_spu_size )
 342     {
 343         msg_Err( p_dec, "uh-oh, we went too far (0x%.4x > 0x%.4x)",
 344                  i_index, p_sys->i_spu_size );
 345         return VLC_EGENERIC;
 346     }
 347
 348     if( !p_spu->i_start )
 349     {
 350         msg_Err( p_dec, "no `start display' command" );
 351     }
 352
 353     if( p_spu->i_stop <= p_spu->i_start && !p_spu->b_ephemer )
 354     {
 355         /* This subtitle will live for 5 seconds or until the next subtitle */
 356         p_spu->i_stop = p_spu->i_start + (mtime_t)500 * 11000;
 357         p_spu->b_ephemer = VLC_TRUE;
 358     }
 359
 360     /* Get rid of padding bytes */
 361     if( p_sys->i_spu_size > i_index + 1 )
 362     {
 363         /* Zero or one padding byte are quite usual
 364          * More than one padding byte - this is very strange, but
 365          * we can ignore them. */
 366         msg_Warn( p_dec, "%i padding bytes, we usually get 0 or 1 of them",
 367                   p_sys->i_spu_size - i_index );
 368     }
 369
 370     /* Successfully parsed ! */
 371     return VLC_SUCCESS;
 372 }
 373
 374 /*****************************************************************************
 375  * ParseRLE: parse the RLE part of the subtitle
 376  *****************************************************************************
 377  * This part parses the subtitle graphical data and stores it in a more
 378  * convenient structure for later decoding. For more information on the
 379  * subtitles format, see http://sam.zoy.org/doc/dvd/subtitles/index.html
 380  *****************************************************************************/
 381 static int ParseRLE( decoder_t *p_dec, subpicture_t * p_spu,
 382                      subpicture_data_t *p_spu_data )
 383 {
 384     decoder_sys_t *p_sys = p_dec->p_sys;
 385     uint8_t       *p_src = &p_sys->buffer[4];
 386
 387     unsigned int i_code;
 388
 389     unsigned int i_width = p_spu->i_width;
 390     unsigned int i_height = p_spu->i_height;
 391     unsigned int i_x, i_y;
 392
 393     uint16_t *p_dest = (uint16_t *)p_spu_data->p_data;
 394
 395     /* The subtitles are interlaced, we need two offsets */
 396     unsigned int  i_id = 0;                   /* Start on the even SPU layer */
 397     unsigned int  pi_table[ 2 ];
 398     unsigned int *pi_offset;
 399
 400     /* Cropping */
 401     vlc_bool_t b_empty_top = VLC_TRUE;
 402     unsigned int i_skipped_top = 0, i_skipped_bottom = 0;
 403     unsigned int i_transparent_code = 0;
 404
 405     /* Colormap statistics */
 406     int i_border = -1;
 407     int stats[4]; stats[0] = stats[1] = stats[2] = stats[3] = 0;
 408
 409     pi_table[ 0 ] = p_spu_data->pi_offset[ 0 ] << 1;
 410     pi_table[ 1 ] = p_spu_data->pi_offset[ 1 ] << 1;
 411
 412     for( i_y = 0 ; i_y < i_height ; i_y++ )
 413     {
 414         pi_offset = pi_table + i_id;
 415
 416         for( i_x = 0 ; i_x < i_width ; i_x += i_code >> 2 )
 417         {
 418             i_code = AddNibble( 0, p_src, pi_offset );
 419
 420             if( i_code < 0x04 )
 421             {
 422                 i_code = AddNibble( i_code, p_src, pi_offset );
 423
 424                 if( i_code < 0x10 )
 425                 {
 426                     i_code = AddNibble( i_code, p_src, pi_offset );
 427
 428                     if( i_code < 0x040 )
 429                     {
 430                         i_code = AddNibble( i_code, p_src, pi_offset );
 431
 432                         if( i_code < 0x0100 )
 433                         {
 434                             /* If the 14 first bits are set to 0, then it's a
 435                              * new line. We emulate it. */
 436                             if( i_code < 0x0004 )
 437                             {
 438                                 i_code |= ( i_width - i_x ) << 2;
 439                             }
 440                             else
 441                             {
 442                                 /* We have a boo boo ! */
 443                                 msg_Err( p_dec, "unknown RLE code "
 444                                          "0x%.4x", i_code );
 445                                 return VLC_EGENERIC;
 446                             }
 447                         }
 448                     }
 449                 }
 450             }
 451
 452             if( ( (i_code >> 2) + i_x + i_y * i_width ) > i_height * i_width )
 453             {
 454                 msg_Err( p_dec, "out of bounds, %i at (%i,%i) is out of %ix%i",
 455                          i_code >> 2, i_x, i_y, i_width, i_height );
 456                 return VLC_EGENERIC;
 457             }
 458
 459             /* Try to find the border color */
 460             if( p_spu_data->pi_alpha[ i_code & 0x3 ] != 0x00 )
 461             {
 462                 i_border = i_code & 0x3;
 463                 stats[i_border] += i_code >> 2;
 464             }
 465
 466             /* Auto crop subtitles (a lot more optimized) */
 467             if( p_spu_data->b_auto_crop )
 468             {
 469                 if( !i_y )
 470                 {
 471                     /* We assume that if the first line is transparent, then
 472                      * it is using the palette index for the
 473                      * (background) transparent color */
 474                     if( (i_code >> 2) == i_width &&
 475                         p_spu_data->pi_alpha[ i_code & 0x3 ] == 0x00 )
 476                     {
 477                         i_transparent_code = i_code;
 478                     }
 479                     else
 480                     {
 481                         p_spu_data->b_auto_crop = VLC_FALSE;
 482                     }
 483                 }
 484
 485                 if( i_code == i_transparent_code )
 486                 {
 487                     if( b_empty_top )
 488                     {
 489                         /* This is a blank top line, we skip it */
 490                       i_skipped_top++;
 491                     }
 492                     else
 493                     {
 494                         /* We can't be sure the current lines will be skipped,
 495                          * so we store the code just in case. */
 496                       *p_dest++ = i_code;
 497                       i_skipped_bottom++;
 498                     }
 499                 }
 500                 else
 501                 {
 502                     /* We got a valid code, store it */
 503                     *p_dest++ = i_code;
 504
 505                     /* Valid code means no blank line */
 506                     b_empty_top = VLC_FALSE;
 507                     i_skipped_bottom = 0;
 508                 }
 509             }
 510             else
 511             {
 512                 *p_dest++ = i_code;
 513             }
 514         }
 515
 516         /* Check that we didn't go too far */
 517         if( i_x > i_width )
 518         {
 519             msg_Err( p_dec, "i_x overflowed, %i > %i", i_x, i_width );
 520             return VLC_EGENERIC;
 521         }
 522
 523         /* Byte-align the stream */
 524         if( *pi_offset & 0x1 )
 525         {
 526             (*pi_offset)++;
 527         }
 528
 529         /* Swap fields */
 530         i_id = ~i_id & 0x1;
 531     }
 532
 533     /* We shouldn't get any padding bytes */
 534     if( i_y < i_height )
 535     {
 536         msg_Err( p_dec, "padding bytes found in RLE sequence" );
 537         msg_Err( p_dec, "send mail to <sam@zoy.org> if you "
 538                         "want to help debugging this" );
 539
 540         /* Skip them just in case */
 541         while( i_y < i_height )
 542         {
 543             *p_dest++ = i_width << 2;
 544             i_y++;
 545         }
 546
 547         return VLC_EGENERIC;
 548     }
 549
 550 #ifdef DEBUG_SPUDEC
 551     msg_Dbg( p_dec, "valid subtitle, size: %ix%i, position: %i,%i",
 552              p_spu->i_width, p_spu->i_height, p_spu->i_x, p_spu->i_y );
 553 #endif
 554
 555     /* Crop if necessary */
 556     if( i_skipped_top || i_skipped_bottom )
 557     {
 558 #ifdef DEBUG_SPUDEC
 559         int i_y = p_spu->i_y + i_skipped_top;
 560         int i_height = p_spu->i_height - (i_skipped_top + i_skipped_bottom);
 561 #endif
 562         p_spu_data->i_y_top_offset = i_skipped_top;
 563         p_spu_data->i_y_bottom_offset = i_skipped_bottom;
 564 #ifdef DEBUG_SPUDEC
 565         msg_Dbg( p_dec, "cropped to: %ix%i, position: %i,%i",
 566                  p_spu->i_width, i_height, p_spu->i_x, i_y );
 567 #endif
 568     }
 569
 570     /* Handle color if no palette was found */
 571     if( !p_spu_data->b_palette )
 572     {
 573         int i, i_inner = -1, i_shade = -1;
 574
 575         /* Set the border color */
 576         p_spu_data->pi_yuv[i_border][0] = 0x00;
 577         p_spu_data->pi_yuv[i_border][1] = 0x80;
 578         p_spu_data->pi_yuv[i_border][2] = 0x80;
 579         stats[i_border] = 0;
 580
 581         /* Find the inner colors */
 582         for( i = 0 ; i < 4 && i_inner == -1 ; i++ )
 583         {
 584             if( stats[i] )
 585             {
 586                 i_inner = i;
 587             }
 588         }
 589
 590         for(       ; i < 4 && i_shade == -1 ; i++ )
 591         {
 592             if( stats[i] )
 593             {
 594                 if( stats[i] > stats[i_inner] )
 595                 {
 596                     i_shade = i_inner;
 597                     i_inner = i;
 598                 }
 599                 else
 600                 {
 601                     i_shade = i;
 602                 }
 603             }
 604         }
 605
 606         /* Set the inner color */
 607         if( i_inner != -1 )
 608         {
 609             p_spu_data->pi_yuv[i_inner][0] = 0xff;
 610             p_spu_data->pi_yuv[i_inner][1] = 0x80;
 611             p_spu_data->pi_yuv[i_inner][2] = 0x80;
 612         }
 613
 614         /* Set the anti-aliasing color */
 615         if( i_shade != -1 )
 616         {
 617             p_spu_data->pi_yuv[i_shade][0] = 0x80;
 618             p_spu_data->pi_yuv[i_shade][1] = 0x80;
 619             p_spu_data->pi_yuv[i_shade][2] = 0x80;
 620         }
 621
 622 #ifdef DEBUG_SPUDEC
 623         msg_Dbg( p_dec, "using custom palette (border %i, inner %i, shade %i)",
 624                  i_border, i_inner, i_shade );
 625 #endif
 626     }
 627
 628     return VLC_SUCCESS;
 629 }
 630
 631 static void Render( decoder_t *p_dec, subpicture_t *p_spu,
 632                     subpicture_data_t *p_spu_data )
 633 {
 634     uint8_t *p_p;
 635     int i_x, i_y, i_len, i_color, i_pitch;
 636     uint16_t *p_source = (uint16_t *)p_spu_data->p_data;
 637     video_format_t fmt;
 638
 639     /* Create a new subpicture region */
 640     memset( &fmt, 0, sizeof(video_format_t) );
 641     fmt.i_chroma = VLC_FOURCC('Y','U','V','P');
 642     fmt.i_aspect = 0; /* 0 means use aspect ratio of background video */
 643     fmt.i_width = fmt.i_visible_width = p_spu->i_width;
 644     fmt.i_height = fmt.i_visible_height = p_spu->i_height -
 645         p_spu_data->i_y_top_offset - p_spu_data->i_y_bottom_offset;
 646     fmt.i_x_offset = fmt.i_y_offset = 0;
 647     p_spu->p_region = p_spu->pf_create_region( VLC_OBJECT(p_dec), &fmt );
 648     if( !p_spu->p_region )
 649     {
 650         msg_Err( p_dec, "cannot allocate SPU region" );
 651         return;
 652     }
 653
 654     p_spu->p_region->i_x = 0;
 655     p_spu->p_region->i_y = p_spu_data->i_y_top_offset;
 656     p_p = p_spu->p_region->picture.p->p_pixels;
 657     i_pitch = p_spu->p_region->picture.p->i_pitch;
 658
 659     /* Build palette */
 660     fmt.p_palette->i_entries = 4;
 661     for( i_x = 0; i_x < fmt.p_palette->i_entries; i_x++ )
 662     {
 663         fmt.p_palette->palette[i_x][0] = p_spu_data->pi_yuv[i_x][0];
 664         fmt.p_palette->palette[i_x][1] = p_spu_data->pi_yuv[i_x][1];
 665         fmt.p_palette->palette[i_x][2] = p_spu_data->pi_yuv[i_x][2];
 666         fmt.p_palette->palette[i_x][3] =
 667             p_spu_data->pi_alpha[i_x] == 0xf ? 0xff :
 668             p_spu_data->pi_alpha[i_x] << 4;
 669     }
 670
 671     /* Draw until we reach the bottom of the subtitle */
 672     for( i_y = 0; i_y < (int)fmt.i_height * i_pitch; i_y += i_pitch )
 673     {
 674         /* Draw until we reach the end of the line */
 675         for( i_x = 0 ; i_x < (int)fmt.i_width; i_x += i_len )
 676         {
 677             /* Get the RLE part, then draw the line */
 678             i_color = *p_source & 0x3;
 679             i_len = *p_source++ >> 2;
 680             memset( p_p + i_x + i_y, i_color, i_len );
 681         }
 682     }
 683 }