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