git.sesse.net Git - vlc/blob - modules/codec/subtitles/subsdec.c

   1 /*****************************************************************************
   2  * subsdec.c : text subtitles decoder
   3  *****************************************************************************
   4  * Copyright (C) 2000-2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@videolan.org>
   8  *          Samuel Hocevar <sam@zoy.org>
   9  *          Derk-Jan Hartman <hartman at videolan dot org>
  10  *          Bernie Purcell <bitmap@videolan.org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30
  31 #include "subsdec.h"
  32
  33 /*****************************************************************************
  34  * Local prototypes
  35  *****************************************************************************/
  36 static int  OpenDecoder   ( vlc_object_t * );
  37 static void CloseDecoder  ( vlc_object_t * );
  38
  39 static subpicture_t   *DecodeBlock   ( decoder_t *, block_t ** );
  40 static subpicture_t   *ParseText     ( decoder_t *, block_t * );
  41 static char           *StripTags      ( char * );
  42 static char           *CreateHtmlSubtitle ( char * );
  43
  44
  45 /*****************************************************************************
  46  * Module descriptor.
  47  *****************************************************************************/
  48 static const char *ppsz_encodings[] = { DEFAULT_NAME, "ASCII", "UTF-8", "",
  49     "ISO-8859-1", "CP1252", "MacRoman", "MacIceland","ISO-8859-15", "",
  50     "ISO-8859-2", "CP1250", "MacCentralEurope", "MacCroatian", "MacRomania", "",
  51     "ISO-8859-5", "CP1251", "MacCyrillic", "MacUkraine", "KOI8-R", "KOI8-U", "KOI8-RU", "",
  52     "ISO-8859-6", "CP1256", "MacArabic", "",
  53     "ISO-8859-7", "CP1253", "MacGreek", "",
  54     "ISO-8859-8", "CP1255", "MacHebrew", "",
  55     "ISO-8859-9", "CP1254", "MacTurkish", "",
  56     "ISO-8859-13", "CP1257", "",
  57     "ISO-2022-JP", "ISO-2022-JP-1", "ISO-2022-JP-2", "EUC-JP", "SHIFT_JIS", "",
  58     "ISO-2022-CN", "ISO-2022-CN-EXT", "EUC-CN", "EUC-TW", "BIG5", "BIG5-HKSCS", "",
  59     "ISO-2022-KR", "EUC-KR", "",
  60     "MacThai", "KOI8-T", "",
  61     "ISO-8859-3", "ISO-8859-4", "ISO-8859-10", "ISO-8859-14", "ISO-8859-16", "",
  62     "CP850", "CP862", "CP866", "CP874", "CP932", "CP949", "CP950", "CP1133", "CP1258", "",
  63     "Macintosh", "",
  64     "UTF-7", "UTF-16", "UTF-16BE", "UTF-16LE", "UTF-32", "UTF-32BE", "UTF-32LE",
  65     "C99", "JAVA", "UCS-2", "UCS-2BE", "UCS-2LE", "UCS-4", "UCS-4BE", "UCS-4LE", "",
  66     "HZ", "GBK", "GB18030", "JOHAB", "ARMSCII-8",
  67     "Georgian-Academy", "Georgian-PS", "TIS-620", "MuleLao-1", "VISCII", "TCVN",
  68     "HPROMAN8", "NEXTSTEP" };
  69 /*
  70 SSA supports charset selection.
  71 The following known charsets are used:
  72
  73 0 = Ansi - Western European
  74 1 = default
  75 2 = symbol
  76 3 = invalid
  77 77 = Mac
  78 128 = Japanese (Shift JIS)
  79 129 = Hangul
  80 130 = Johab
  81 134 = GB2312 Simplified Chinese
  82 136 = Big5 Traditional Chinese
  83 161 = Greek
  84 162 = Turkish
  85 163 = Vietnamese
  86 177 = Hebrew
  87 178 = Arabic
  88 186 = Baltic
  89 204 = Russian (Cyrillic)
  90 222 = Thai
  91 238 = Eastern European
  92 254 = PC 437
  93 */
  94
  95 static int  pi_justification[] = { 0, 1, 2 };
  96 static const char *ppsz_justification_text[] = {N_("Center"),N_("Left"),N_("Right")};
  97
  98 #define ENCODING_TEXT N_("Subtitles text encoding")
  99 #define ENCODING_LONGTEXT N_("Set the encoding used in text subtitles")
 100 #define ALIGN_TEXT N_("Subtitles justification")
 101 #define ALIGN_LONGTEXT N_("Set the justification of subtitles")
 102 #define AUTODETECT_UTF8_TEXT N_("UTF-8 subtitles autodetection")
 103 #define AUTODETECT_UTF8_LONGTEXT N_("This enables automatic detection of " \
 104             "UTF-8 encoding within subtitles files.")
 105 #define FORMAT_TEXT N_("Formatted Subtitles")
 106 #define FORMAT_LONGTEXT N_("Some subtitle formats allow for text formatting. " \
 107  "VLC partly implements this, but you can choose to disable all formatting.")
 108
 109
 110 vlc_module_begin();
 111     set_shortname( _("Subtitles"));
 112     set_description( _("Text subtitles decoder") );
 113     set_capability( "decoder", 50 );
 114     set_callbacks( OpenDecoder, CloseDecoder );
 115     set_category( CAT_INPUT );
 116     set_subcategory( SUBCAT_INPUT_SCODEC );
 117
 118     add_integer( "subsdec-align", 0, NULL, ALIGN_TEXT, ALIGN_LONGTEXT,
 119                  VLC_FALSE );
 120         change_integer_list( pi_justification, ppsz_justification_text, 0 );
 121     add_string( "subsdec-encoding", DEFAULT_NAME, NULL,
 122                 ENCODING_TEXT, ENCODING_LONGTEXT, VLC_FALSE );
 123         change_string_list( ppsz_encodings, 0, 0 );
 124     add_bool( "subsdec-autodetect-utf8", VLC_TRUE, NULL,
 125               AUTODETECT_UTF8_TEXT, AUTODETECT_UTF8_LONGTEXT, VLC_FALSE );
 126     add_bool( "subsdec-formatted", VLC_TRUE, NULL, FORMAT_TEXT, FORMAT_LONGTEXT,
 127                  VLC_FALSE );
 128 vlc_module_end();
 129
 130 /*****************************************************************************
 131  * OpenDecoder: probe the decoder and return score
 132  *****************************************************************************
 133  * Tries to launch a decoder and return score so that the interface is able
 134  * to chose.
 135  *****************************************************************************/
 136 static int OpenDecoder( vlc_object_t *p_this )
 137 {
 138     decoder_t     *p_dec = (decoder_t*)p_this;
 139     decoder_sys_t *p_sys;
 140     vlc_value_t    val;
 141
 142     switch( p_dec->fmt_in.i_codec )
 143     {
 144         case VLC_FOURCC('s','u','b','t'):
 145         case VLC_FOURCC('s','s','a',' '):
 146         case VLC_FOURCC('t','1','4','0'):
 147             break;
 148         default:
 149             return VLC_EGENERIC;
 150     }
 151
 152     p_dec->pf_decode_sub = DecodeBlock;
 153
 154     /* Allocate the memory needed to store the decoder's structure */
 155     p_dec->p_sys = p_sys = malloc( sizeof( *p_sys ) );
 156     if( p_sys == NULL )
 157     {
 158         msg_Err( p_dec, "out of memory" );
 159         return VLC_ENOMEM;
 160     }
 161
 162     /* init of p_sys */
 163     memset( p_sys, 0, sizeof( *p_sys ) );
 164     p_sys->i_align = 0;
 165     p_sys->iconv_handle = (vlc_iconv_t)-1;
 166     p_sys->b_autodetect_utf8 = VLC_FALSE;
 167     p_sys->b_ass = VLC_FALSE;
 168     p_sys->i_original_height = -1;
 169     p_sys->i_original_width = -1;
 170     TAB_INIT( p_sys->i_ssa_styles, p_sys->pp_ssa_styles );
 171     TAB_INIT( p_sys->i_images, p_sys->pp_images );
 172
 173     char *psz_charset = NULL;
 174
 175     if( p_dec->fmt_in.i_codec == VLC_FOURCC('t','1','4','0') )
 176         psz_charset = strdup( "UTF-8" ); /* IUT T.140 is always using UTF-8 */
 177     else
 178     /* First try demux-specified encoding */
 179     if( p_dec->fmt_in.subs.psz_encoding && *p_dec->fmt_in.subs.psz_encoding )
 180     {
 181         psz_charset = strdup (p_dec->fmt_in.subs.psz_encoding);
 182         msg_Dbg (p_dec, "trying demuxer-specified character encoding: %s",
 183                  p_dec->fmt_in.subs.psz_encoding ?: "not specified");
 184     }
 185
 186     /* Second, try configured encoding */
 187     if (psz_charset == NULL)
 188     {
 189         psz_charset = var_CreateGetNonEmptyString (p_dec, "subsdec-encoding");
 190         if ((psz_charset != NULL) && !strcasecmp (psz_charset, DEFAULT_NAME))
 191         {
 192             free (psz_charset);
 193             psz_charset = NULL;
 194         }
 195
 196         msg_Dbg (p_dec, "trying configured character encoding: %s",
 197                  psz_charset ?: "not specified");
 198     }
 199
 200     /* Third, try "local" encoding with optional UTF-8 autodetection */
 201     if (psz_charset == NULL)
 202     {
 203         psz_charset = strdup (GetFallbackEncoding ());
 204         msg_Dbg (p_dec, "trying default character encoding: %s",
 205                  psz_charset ?: "not specified");
 206
 207         if (var_CreateGetBool (p_dec, "subsdec-autodetect-utf8"))
 208         {
 209             msg_Dbg (p_dec, "using automatic UTF-8 detection");
 210             p_sys->b_autodetect_utf8 = VLC_TRUE;
 211         }
 212     }
 213
 214     if (psz_charset == NULL)
 215     {
 216         psz_charset = strdup ("UTF-8");
 217         msg_Dbg (p_dec, "trying hard-coded character encoding: %s",
 218                  psz_charset ? psz_charset : "error");
 219     }
 220
 221     if (psz_charset == NULL)
 222     {
 223         free (p_sys);
 224         return VLC_ENOMEM;
 225     }
 226
 227     if (strcasecmp (psz_charset, "UTF-8") && strcasecmp (psz_charset, "utf8"))
 228     {
 229         p_sys->iconv_handle = vlc_iconv_open ("UTF-8", psz_charset);
 230         if (p_sys->iconv_handle == (vlc_iconv_t)(-1))
 231             msg_Err (p_dec, "cannot convert from %s: %m", psz_charset);
 232     }
 233     free (psz_charset);
 234
 235     var_Create( p_dec, "subsdec-align", VLC_VAR_INTEGER | VLC_VAR_DOINHERIT );
 236     var_Get( p_dec, "subsdec-align", &val );
 237     p_sys->i_align = val.i_int;
 238
 239     if( p_dec->fmt_in.i_codec == VLC_FOURCC('s','s','a',' ')
 240      && var_CreateGetBool( p_dec, "subsdec-formatted" ) )
 241     {
 242         if( p_dec->fmt_in.i_extra > 0 )
 243             ParseSSAHeader( p_dec );
 244     }
 245
 246     return VLC_SUCCESS;
 247 }
 248
 249 /****************************************************************************
 250  * DecodeBlock: the whole thing
 251  ****************************************************************************
 252  * This function must be fed with complete subtitles units.
 253  ****************************************************************************/
 254 static subpicture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 255 {
 256     subpicture_t *p_spu = NULL;
 257
 258     if( !pp_block || *pp_block == NULL ) return NULL;
 259
 260     p_spu = ParseText( p_dec, *pp_block );
 261
 262     block_Release( *pp_block );
 263     *pp_block = NULL;
 264
 265     return p_spu;
 266 }
 267
 268 /*****************************************************************************
 269  * CloseDecoder: clean up the decoder
 270  *****************************************************************************/
 271 static void CloseDecoder( vlc_object_t *p_this )
 272 {
 273     decoder_t *p_dec = (decoder_t *)p_this;
 274     decoder_sys_t *p_sys = p_dec->p_sys;
 275
 276     if( p_sys->iconv_handle != (vlc_iconv_t)-1 )
 277         vlc_iconv_close( p_sys->iconv_handle );
 278
 279     if( p_sys->pp_ssa_styles )
 280     {
 281         int i;
 282         for( i = 0; i < p_sys->i_ssa_styles; i++ )
 283         {
 284             if( !p_sys->pp_ssa_styles[i] )
 285                 continue;
 286
 287             if( p_sys->pp_ssa_styles[i]->psz_stylename )
 288                 free( p_sys->pp_ssa_styles[i]->psz_stylename );
 289             if( p_sys->pp_ssa_styles[i]->font_style.psz_fontname )
 290                 free( p_sys->pp_ssa_styles[i]->font_style.psz_fontname );
 291             if( p_sys->pp_ssa_styles[i] )
 292                 free( p_sys->pp_ssa_styles[i] );
 293         }
 294         TAB_CLEAN( p_sys->i_ssa_styles, p_sys->pp_ssa_styles );
 295     }
 296     if( p_sys->pp_images )
 297     {
 298         int i;
 299         for( i = 0; i < p_sys->i_images; i++ )
 300         {
 301             if( !p_sys->pp_images[i] )
 302                 continue;
 303
 304             if( p_sys->pp_images[i]->p_pic )
 305                 p_sys->pp_images[i]->p_pic->pf_release( p_sys->pp_images[i]->p_pic );
 306             if( p_sys->pp_images[i]->psz_filename )
 307                 free( p_sys->pp_images[i]->psz_filename );
 308
 309             free( p_sys->pp_images[i] );
 310         }
 311         TAB_CLEAN( p_sys->i_images, p_sys->pp_images );
 312     }
 313
 314     free( p_sys );
 315 }
 316
 317 /*****************************************************************************
 318  * ParseText: parse an text subtitle packet and send it to the video output
 319  *****************************************************************************/
 320 static subpicture_t *ParseText( decoder_t *p_dec, block_t *p_block )
 321 {
 322     decoder_sys_t *p_sys = p_dec->p_sys;
 323     subpicture_t *p_spu = NULL;
 324     char *psz_subtitle = NULL;
 325     video_format_t fmt;
 326
 327     /* We cannot display a subpicture with no date */
 328     if( p_block->i_pts == 0 )
 329     {
 330         msg_Warn( p_dec, "subtitle without a date" );
 331         return NULL;
 332     }
 333
 334     /* Check validity of packet data */
 335     /* An "empty" line containing only \0 can be used to force
 336        and ephemer picture from the screen */
 337     if( p_block->i_buffer < 1 )
 338     {
 339         msg_Warn( p_dec, "no subtitle data" );
 340         return NULL;
 341     }
 342
 343     /* Should be resiliant against bad subtitles */
 344     psz_subtitle = strndup( (const char *)p_block->p_buffer,
 345                             p_block->i_buffer );
 346     if( psz_subtitle == NULL )
 347         return NULL;
 348
 349     if( p_sys->iconv_handle == (vlc_iconv_t)-1 )
 350     {
 351         if (EnsureUTF8( psz_subtitle ) == NULL)
 352         {
 353             msg_Err( p_dec, _("failed to convert subtitle encoding.\n"
 354                      "Try manually setting a character-encoding "
 355                      "before you open the file.") );
 356         }
 357     }
 358     else
 359     {
 360
 361         if( p_sys->b_autodetect_utf8 )
 362         {
 363             if( IsUTF8( psz_subtitle ) == NULL )
 364             {
 365                 msg_Dbg( p_dec, "invalid UTF-8 sequence: "
 366                          "disabling UTF-8 subtitles autodetection" );
 367                 p_sys->b_autodetect_utf8 = VLC_FALSE;
 368             }
 369         }
 370
 371         if( !p_sys->b_autodetect_utf8 )
 372         {
 373             size_t inbytes_left = strlen( psz_subtitle );
 374             size_t outbytes_left = 6 * inbytes_left;
 375             char *psz_new_subtitle = malloc( outbytes_left + 1 );
 376             char *psz_convert_buffer_out = psz_new_subtitle;
 377             const char *psz_convert_buffer_in = psz_subtitle;
 378
 379             size_t ret = vlc_iconv( p_sys->iconv_handle,
 380                                     &psz_convert_buffer_in, &inbytes_left,
 381                                     &psz_convert_buffer_out, &outbytes_left );
 382
 383             *psz_convert_buffer_out++ = '\0';
 384             free( psz_subtitle );
 385
 386             if( ( ret == (size_t)(-1) ) || inbytes_left )
 387             {
 388                 free( psz_new_subtitle );
 389                 msg_Err( p_dec, _("failed to convert subtitle encoding.\n"
 390                         "Try manually setting a character-encoding "
 391                                 "before you open the file.") );
 392                 return NULL;
 393             }
 394
 395             psz_subtitle = realloc( psz_new_subtitle,
 396                                     psz_convert_buffer_out - psz_new_subtitle );
 397         }
 398     }
 399
 400     /* Create the subpicture unit */
 401     p_spu = p_dec->pf_spu_buffer_new( p_dec );
 402     if( !p_spu )
 403     {
 404         msg_Warn( p_dec, "can't get spu buffer" );
 405         if( psz_subtitle ) free( psz_subtitle );
 406         return NULL;
 407     }
 408
 409     p_spu->b_pausable = VLC_TRUE;
 410
 411     /* Create a new subpicture region */
 412     memset( &fmt, 0, sizeof(video_format_t) );
 413     fmt.i_chroma = VLC_FOURCC('T','E','X','T');
 414     fmt.i_aspect = 0;
 415     fmt.i_width = fmt.i_height = 0;
 416     fmt.i_x_offset = fmt.i_y_offset = 0;
 417     p_spu->p_region = p_spu->pf_create_region( VLC_OBJECT(p_dec), &fmt );
 418     if( !p_spu->p_region )
 419     {
 420         msg_Err( p_dec, "cannot allocate SPU region" );
 421         if( psz_subtitle ) free( psz_subtitle );
 422         p_dec->pf_spu_buffer_del( p_dec, p_spu );
 423         return NULL;
 424     }
 425
 426     /* Decode and format the subpicture unit */
 427     if( p_dec->fmt_in.i_codec != VLC_FOURCC('s','s','a',' ') )
 428     {
 429         /* Normal text subs, easy markup */
 430         p_spu->p_region->i_align = SUBPICTURE_ALIGN_BOTTOM | p_sys->i_align;
 431         p_spu->i_x = p_sys->i_align ? 20 : 0;
 432         p_spu->i_y = 10;
 433
 434         /* Remove formatting from string */
 435
 436         p_spu->p_region->psz_text = StripTags( psz_subtitle );
 437         if( var_CreateGetBool( p_dec, "subsdec-formatted" ) )
 438         {
 439             p_spu->p_region->psz_html = CreateHtmlSubtitle( psz_subtitle );
 440         }
 441
 442         p_spu->i_start = p_block->i_pts;
 443         p_spu->i_stop = p_block->i_pts + p_block->i_length;
 444         p_spu->b_ephemer = (p_block->i_length == 0);
 445         p_spu->b_absolute = VLC_FALSE;
 446     }
 447     else
 448     {
 449         /* Decode SSA/USF strings */
 450         if( p_dec->fmt_in.i_codec == VLC_FOURCC('s','s','a',' ') )
 451             ParseSSAString( p_dec, psz_subtitle, p_spu );
 452
 453         p_spu->i_start = p_block->i_pts;
 454         p_spu->i_stop = p_block->i_pts + p_block->i_length;
 455         p_spu->b_ephemer = (p_block->i_length == 0);
 456         p_spu->b_absolute = VLC_FALSE;
 457         p_spu->i_original_picture_width = p_sys->i_original_width;
 458         p_spu->i_original_picture_height = p_sys->i_original_height;
 459     }
 460     if( psz_subtitle ) free( psz_subtitle );
 461
 462     return p_spu;
 463 }
 464
 465 char* GotoNextLine( char *psz_text )
 466 {
 467     char *p_newline = psz_text;
 468
 469     while( p_newline[0] != '\0' )
 470     {
 471         if( p_newline[0] == '\n' || p_newline[0] == '\r' )
 472         {
 473             p_newline++;
 474             while( p_newline[0] == '\n' || p_newline[0] == '\r' )
 475                 p_newline++;
 476             break;
 477         }
 478         else p_newline++;
 479     }
 480     return p_newline;
 481 }
 482
 483 /* Function now handles tags with attribute values, and tries
 484  * to deal with &' commands too. It no longer modifies the string
 485  * in place, so that the original text can be reused
 486  */
 487 static char *StripTags( char *psz_subtitle )
 488 {
 489     char *psz_text_start;
 490     char *psz_text;
 491
 492     psz_text = psz_text_start = malloc( strlen( psz_subtitle ) + 1 );
 493     if( !psz_text_start )
 494         return NULL;
 495
 496     while( *psz_subtitle )
 497     {
 498         if( *psz_subtitle == '<' )
 499         {
 500             if( strncasecmp( psz_subtitle, "<br/>", 5 ) == 0 )
 501                 *psz_text++ = '\n';
 502
 503             psz_subtitle += strcspn( psz_subtitle, ">" );
 504         }
 505         else if( *psz_subtitle == '&' )
 506         {
 507             if( !strncasecmp( psz_subtitle, "&lt;", 4 ))
 508             {
 509                 *psz_text++ = '<';
 510                 psz_subtitle += strcspn( psz_subtitle, ";" );
 511             }
 512             else if( !strncasecmp( psz_subtitle, "&gt;", 4 ))
 513             {
 514                 *psz_text++ = '>';
 515                 psz_subtitle += strcspn( psz_subtitle, ";" );
 516             }
 517             else if( !strncasecmp( psz_subtitle, "&amp;", 5 ))
 518             {
 519                 *psz_text++ = '&';
 520                 psz_subtitle += strcspn( psz_subtitle, ";" );
 521             }
 522             else if( !strncasecmp( psz_subtitle, "&quot;", 6 ))
 523             {
 524                 *psz_text++ = '\"';
 525                 psz_subtitle += strcspn( psz_subtitle, ";" );
 526             }
 527             else
 528             {
 529                 /* Assume it is just a normal ampersand */
 530                 *psz_text++ = '&';
 531             }
 532         }
 533         else
 534         {
 535             *psz_text++ = *psz_subtitle;
 536         }
 537
 538         psz_subtitle++;
 539     }
 540     *psz_text = '\0';
 541     psz_text_start = realloc( psz_text_start, strlen( psz_text_start ) + 1 );
 542
 543     return psz_text_start;
 544 }
 545
 546 /* Try to respect any style tags present in the subtitle string. The main
 547  * problem here is a lack of adequate specs for the subtitle formats.
 548  * SSA/ASS and USF are both detail spec'ed -- but they are handled elsewhere.
 549  * SAMI has a detailed spec, but extensive rework is needed in the demux
 550  * code to prevent all this style information being excised, as it presently
 551  * does.
 552  * That leaves the others - none of which were (I guess) originally intended
 553  * to be carrying style information. Over time people have used them that way.
 554  * In the absence of specifications from which to work, the tags supported
 555  * have been restricted to the simple set permitted by the USF DTD, ie. :
 556  *  Basic: <br>, <i>, <b>, <u>
 557  *  Extended: <font>
 558  *    Attributes: face
 559  *                family
 560  *                size
 561  *                color
 562  *                outline-color
 563  *                shadow-color
 564  *                outline-level
 565  *                shadow-level
 566  *                back-color
 567  *                alpha
 568  * There is also the further restriction that the subtitle be well-formed
 569  * as an XML entity, ie. the HTML sentence:
 570  *        <b><i>Bold and Italics</b></i>
 571  * doesn't qualify because the tags aren't nested one inside the other.
 572  * <text> tags are automatically added to the output to ensure
 573  * well-formedness.
 574  * If the text doesn't qualify for any reason, a NULL string is
 575  * returned, and the rendering engine will fall back to the
 576  * plain text version of the subtitle.
 577  */
 578 static char *CreateHtmlSubtitle( char *psz_subtitle )
 579 {
 580     char    psz_tagStack[ 100 ];
 581     size_t  i_buf_size     = strlen( psz_subtitle ) + 100;
 582     char   *psz_html_start = malloc( i_buf_size );
 583
 584     psz_tagStack[ 0 ] = '\0';
 585
 586     if( psz_html_start != NULL )
 587     {
 588         char *psz_html = psz_html_start;
 589
 590         strcpy( psz_html, "<text>" );
 591         psz_html += 6;
 592
 593         while( *psz_subtitle )
 594         {
 595             if( *psz_subtitle == '\n' )
 596             {
 597                 strcpy( psz_html, "<br/>" );
 598                 psz_html += 5;
 599                 psz_subtitle++;
 600             }
 601             else if( *psz_subtitle == '<' )
 602             {
 603                 if( !strncasecmp( psz_subtitle, "<br/>", 5 ))
 604                 {
 605                     strcpy( psz_html, "<br/>" );
 606                     psz_html += 5;
 607                     psz_subtitle += 5;
 608                 }
 609                 else if( !strncasecmp( psz_subtitle, "<b>", 3 ) )
 610                 {
 611                     strcpy( psz_html, "<b>" );
 612                     strcat( psz_tagStack, "b" );
 613                     psz_html += 3;
 614                     psz_subtitle += 3;
 615                 }
 616                 else if( !strncasecmp( psz_subtitle, "<i>", 3 ) )
 617                 {
 618                     strcpy( psz_html, "<i>" );
 619                     strcat( psz_tagStack, "i" );
 620                     psz_html += 3;
 621                     psz_subtitle += 3;
 622                 }
 623                 else if( !strncasecmp( psz_subtitle, "<u>", 3 ) )
 624                 {
 625                     strcpy( psz_html, "<u>" );
 626                     strcat( psz_tagStack, "u" );
 627                     psz_html += 3;
 628                     psz_subtitle += 3;
 629                 }
 630                 else if( !strncasecmp( psz_subtitle, "<font ", 6 ))
 631                 {
 632                     const char *psz_attribs[] = { "face=\"", "family=\"", "size=\"",
 633                             "color=\"", "outline-color=\"", "shadow-color=\"",
 634                             "outline-level=\"", "shadow-level=\"", "back-color=\"",
 635                             "alpha=\"", NULL };
 636
 637                     strcpy( psz_html, "<font " );
 638                     strcat( psz_tagStack, "f" );
 639                     psz_html += 6;
 640                     psz_subtitle += 6;
 641
 642                     while( *psz_subtitle != '>' )
 643                     {
 644                         int  k;
 645
 646                         for( k=0; psz_attribs[ k ]; k++ )
 647                         {
 648                             int i_len = strlen( psz_attribs[ k ] );
 649
 650                             if( !strncasecmp( psz_subtitle, psz_attribs[ k ], i_len ))
 651                             {
 652                                 i_len += strcspn( psz_subtitle + i_len, "\"" ) + 1;
 653
 654                                 strncpy( psz_html, psz_subtitle, i_len );
 655                                 psz_html += i_len;
 656                                 psz_subtitle += i_len;
 657                                 break;
 658                             }
 659                         }
 660                         if( psz_attribs[ k ] == NULL )
 661                         {
 662                             /* Jump over unrecognised tag */
 663                             int i_len = strcspn( psz_subtitle, "\"" ) + 1;
 664
 665                             i_len += strcspn( psz_subtitle + i_len, "\"" ) + 1;
 666                             psz_subtitle += i_len;
 667                         }
 668                         while (*psz_subtitle == ' ')
 669                             *psz_html++ = *psz_subtitle++;
 670                     }
 671                     *psz_html++ = *psz_subtitle++;
 672                 }
 673                 else if( !strncmp( psz_subtitle, "</", 2 ))
 674                 {
 675                     vlc_bool_t  b_match     = VLC_FALSE;
 676                     int         i_len       = strlen( psz_tagStack ) - 1;
 677                     char       *psz_lastTag = NULL;
 678
 679                     if( i_len >= 0 )
 680                     {
 681                         psz_lastTag = psz_tagStack + i_len;
 682                         i_len = 0;
 683
 684                         switch( *psz_lastTag )
 685                         {
 686                             case 'b':
 687                                 b_match = !strncasecmp( psz_subtitle, "</b>", 4 );
 688                                 i_len   = 4;
 689                                 break;
 690                             case 'i':
 691                                 b_match = !strncasecmp( psz_subtitle, "</i>", 4 );
 692                                 i_len   = 4;
 693                                 break;
 694                             case 'u':
 695                                 b_match = !strncasecmp( psz_subtitle, "</u>", 4 );
 696                                 i_len   = 4;
 697                                 break;
 698                             case 'f':
 699                                 b_match = !strncasecmp( psz_subtitle, "</font>", 7 );
 700                                 i_len   = 7;
 701                                 break;
 702                         }
 703                     }
 704                     if( ! b_match )
 705                     {
 706                         /* Not well formed -- kill everything */
 707                         free( psz_html_start );
 708                         psz_html_start = NULL;
 709                         break;
 710                     }
 711                     *psz_lastTag = '\0';
 712                     strncpy( psz_html, psz_subtitle, i_len );
 713                     psz_html += i_len;
 714                     psz_subtitle += i_len;
 715                 }
 716                 else
 717                 {
 718                     psz_subtitle += strcspn( psz_subtitle, ">" );
 719                 }
 720             }
 721             else if( *psz_subtitle == '&' )
 722             {
 723                 if( !strncasecmp( psz_subtitle, "&lt;", 4 ))
 724                 {
 725                     strcpy( psz_html, "&lt;" );
 726                     psz_html += 4;
 727                     psz_subtitle += 4;
 728                 }
 729                 else if( !strncasecmp( psz_subtitle, "&gt;", 4 ))
 730                 {
 731                     strcpy( psz_html, "&gt;" );
 732                     psz_html += 4;
 733                     psz_subtitle += 4;
 734                 }
 735                 else if( !strncasecmp( psz_subtitle, "&amp;", 5 ))
 736                 {
 737                     strcpy( psz_html, "&amp;" );
 738                     psz_html += 5;
 739                     psz_subtitle += 5;
 740                 }
 741                 else
 742                 {
 743                     strcpy( psz_html, "&amp;" );
 744                     psz_html += 5;
 745                     psz_subtitle++;
 746                 }
 747             }
 748             else
 749             {
 750                 *psz_html = *psz_subtitle;
 751                 if( psz_html > psz_html_start )
 752                 {
 753                     /* Check for double whitespace */
 754                     if((( *psz_html == ' ' ) ||
 755                         ( *psz_html == '\t' )) &&
 756                        (( *(psz_html-1) == ' ' ) ||
 757                         ( *(psz_html-1) == '\t' )))
 758                     {
 759                         strcpy( psz_html, NO_BREAKING_SPACE );
 760                         psz_html += strlen( NO_BREAKING_SPACE ) - 1;
 761                     }
 762                 }
 763                 psz_html++;
 764                 psz_subtitle++;
 765             }
 766
 767             if( ( size_t )( psz_html - psz_html_start ) > i_buf_size - 10 )
 768             {
 769                 int i_len = psz_html - psz_html_start;
 770
 771                 i_buf_size += 100;
 772                 psz_html_start = realloc( psz_html_start, i_buf_size );
 773                 psz_html = psz_html_start + i_len;
 774                 *psz_html = '\0';
 775             }
 776         }
 777         strcpy( psz_html, "</text>" );
 778         psz_html += 7;
 779
 780         if( psz_tagStack[ 0 ] != '\0' )
 781         {
 782             /* Not well formed -- kill everything */
 783             free( psz_html_start );
 784             psz_html_start = NULL;
 785         }
 786         else if( psz_html_start )
 787         {
 788             /* Shrink the memory requirements */
 789             psz_html_start = realloc( psz_html_start,  psz_html - psz_html_start + 1 );
 790         }
 791     }
 792     return psz_html_start;
 793 }