Fixed subtitle duration when rate != default.
[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 #include <vlc_plugin.h>
36
37 /*****************************************************************************
38  * Local prototypes
39  *****************************************************************************/
40 static int  OpenDecoder   ( vlc_object_t * );
41 static void CloseDecoder  ( vlc_object_t * );
42
43 static subpicture_t   *DecodeBlock   ( decoder_t *, block_t ** );
44 static subpicture_t   *ParseText     ( decoder_t *, block_t * );
45 static char           *StripTags      ( char * );
46 static char           *CreateHtmlSubtitle ( char * );
47
48
49 /*****************************************************************************
50  * Module descriptor.
51  *****************************************************************************/
52 static const char *const ppsz_encodings[] = {
53     DEFAULT_NAME, "ASCII", "UTF-8", "",
54     "ISO-8859-1", "CP1252", "MacRoman", "MacIceland","ISO-8859-15", "",
55     "ISO-8859-2", "CP1250", "MacCentralEurope", "MacCroatian", "MacRomania", "",
56     "ISO-8859-5", "CP1251", "MacCyrillic", "MacUkraine", "KOI8-R", "KOI8-U", "KOI8-RU", "",
57     "ISO-8859-6", "CP1256", "MacArabic", "",
58     "ISO-8859-7", "CP1253", "MacGreek", "",
59     "ISO-8859-8", "CP1255", "MacHebrew", "",
60     "ISO-8859-9", "CP1254", "MacTurkish", "",
61     "ISO-8859-13", "CP1257", "",
62     "ISO-2022-JP", "ISO-2022-JP-1", "ISO-2022-JP-2", "EUC-JP", "SHIFT_JIS", "",
63     "ISO-2022-CN", "ISO-2022-CN-EXT", "EUC-CN", "EUC-TW", "BIG5", "BIG5-HKSCS", "",
64     "ISO-2022-KR", "EUC-KR", "",
65     "MacThai", "KOI8-T", "",
66     "ISO-8859-3", "ISO-8859-4", "ISO-8859-10", "ISO-8859-14", "ISO-8859-16", "",
67     "CP850", "CP862", "CP866", "CP874", "CP932", "CP949", "CP950", "CP1133", "CP1258", "",
68     "Macintosh", "",
69     "UTF-7", "UTF-16", "UTF-16BE", "UTF-16LE", "UTF-32", "UTF-32BE", "UTF-32LE",
70     "C99", "JAVA", "UCS-2", "UCS-2BE", "UCS-2LE", "UCS-4", "UCS-4BE", "UCS-4LE", "",
71     "HZ", "GBK", "GB18030", "JOHAB", "ARMSCII-8",
72     "Georgian-Academy", "Georgian-PS", "TIS-620", "MuleLao-1", "VISCII", "TCVN",
73     "HPROMAN8", "NEXTSTEP" };
74 /*
75 SSA supports charset selection.
76 The following known charsets are used:
77
78 0 = Ansi - Western European
79 1 = default
80 2 = symbol
81 3 = invalid
82 77 = Mac
83 128 = Japanese (Shift JIS)
84 129 = Hangul
85 130 = Johab
86 134 = GB2312 Simplified Chinese
87 136 = Big5 Traditional Chinese
88 161 = Greek
89 162 = Turkish
90 163 = Vietnamese
91 177 = Hebrew
92 178 = Arabic
93 186 = Baltic
94 204 = Russian (Cyrillic)
95 222 = Thai
96 238 = Eastern European
97 254 = PC 437
98 */
99
100 static const int  pi_justification[] = { 0, 1, 2 };
101 static const char *const ppsz_justification_text[] = {
102     N_("Center"),N_("Left"),N_("Right")};
103
104 #define ENCODING_TEXT N_("Subtitles text encoding")
105 #define ENCODING_LONGTEXT N_("Set the encoding used in text subtitles")
106 #define ALIGN_TEXT N_("Subtitles justification")
107 #define ALIGN_LONGTEXT N_("Set the justification of subtitles")
108 #define AUTODETECT_UTF8_TEXT N_("UTF-8 subtitles autodetection")
109 #define AUTODETECT_UTF8_LONGTEXT N_("This enables automatic detection of " \
110             "UTF-8 encoding within subtitles files.")
111 #define FORMAT_TEXT N_("Formatted Subtitles")
112 #define FORMAT_LONGTEXT N_("Some subtitle formats allow for text formatting. " \
113  "VLC partly implements this, but you can choose to disable all formatting.")
114
115
116 vlc_module_begin();
117     set_shortname( N_("Subtitles"));
118     set_description( N_("Text subtitles decoder") );
119     set_capability( "decoder", 50 );
120     set_callbacks( OpenDecoder, CloseDecoder );
121     set_category( CAT_INPUT );
122     set_subcategory( SUBCAT_INPUT_SCODEC );
123
124     add_integer( "subsdec-align", 0, NULL, ALIGN_TEXT, ALIGN_LONGTEXT,
125                  false );
126         change_integer_list( pi_justification, ppsz_justification_text, 0 );
127     add_string( "subsdec-encoding", DEFAULT_NAME, NULL,
128                 ENCODING_TEXT, ENCODING_LONGTEXT, false );
129         change_string_list( ppsz_encodings, 0, 0 );
130     add_bool( "subsdec-autodetect-utf8", true, NULL,
131               AUTODETECT_UTF8_TEXT, AUTODETECT_UTF8_LONGTEXT, false );
132     add_bool( "subsdec-formatted", true, NULL, FORMAT_TEXT, FORMAT_LONGTEXT,
133                  false );
134 vlc_module_end();
135
136 /*****************************************************************************
137  * OpenDecoder: probe the decoder and return score
138  *****************************************************************************
139  * Tries to launch a decoder and return score so that the interface is able
140  * to chose.
141  *****************************************************************************/
142 static int OpenDecoder( vlc_object_t *p_this )
143 {
144     decoder_t     *p_dec = (decoder_t*)p_this;
145     decoder_sys_t *p_sys;
146     vlc_value_t    val;
147
148     switch( p_dec->fmt_in.i_codec )
149     {
150         case VLC_FOURCC('s','u','b','t'):
151         case VLC_FOURCC('s','s','a',' '):
152         case VLC_FOURCC('t','1','4','0'):
153             break;
154         default:
155             return VLC_EGENERIC;
156     }
157
158     p_dec->pf_decode_sub = DecodeBlock;
159
160     /* Allocate the memory needed to store the decoder's structure */
161     p_dec->p_sys = p_sys = malloc( sizeof( *p_sys ) );
162     if( p_sys == NULL )
163         return VLC_ENOMEM;
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 = false;
170     p_sys->b_ass = 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 = 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;
256     block_t *p_block;
257
258     if( !pp_block || *pp_block == NULL )
259         return NULL;
260
261     p_block = *pp_block;
262     if( p_block->i_rate != 0 )
263         p_block->i_length = p_block->i_length * p_block->i_rate / INPUT_RATE_DEFAULT;
264
265     p_spu = ParseText( p_dec, p_block );
266
267     block_Release( p_block );
268     *pp_block = NULL;
269
270     return p_spu;
271 }
272
273 /*****************************************************************************
274  * CloseDecoder: clean up the decoder
275  *****************************************************************************/
276 static void CloseDecoder( vlc_object_t *p_this )
277 {
278     decoder_t *p_dec = (decoder_t *)p_this;
279     decoder_sys_t *p_sys = p_dec->p_sys;
280
281     if( p_sys->iconv_handle != (vlc_iconv_t)-1 )
282         vlc_iconv_close( p_sys->iconv_handle );
283
284     if( p_sys->pp_ssa_styles )
285     {
286         int i;
287         for( i = 0; i < p_sys->i_ssa_styles; i++ )
288         {
289             if( !p_sys->pp_ssa_styles[i] )
290                 continue;
291
292             free( p_sys->pp_ssa_styles[i]->psz_stylename );
293             free( p_sys->pp_ssa_styles[i]->font_style.psz_fontname );
294             free( p_sys->pp_ssa_styles[i] );
295         }
296         TAB_CLEAN( p_sys->i_ssa_styles, p_sys->pp_ssa_styles );
297     }
298     if( p_sys->pp_images )
299     {
300         int i;
301         for( i = 0; i < p_sys->i_images; i++ )
302         {
303             if( !p_sys->pp_images[i] )
304                 continue;
305
306             if( p_sys->pp_images[i]->p_pic )
307                 picture_Release( p_sys->pp_images[i]->p_pic );
308             free( p_sys->pp_images[i]->psz_filename );
309
310             free( p_sys->pp_images[i] );
311         }
312         TAB_CLEAN( p_sys->i_images, p_sys->pp_images );
313     }
314
315     free( p_sys );
316 }
317
318 /*****************************************************************************
319  * ParseText: parse an text subtitle packet and send it to the video output
320  *****************************************************************************/
321 static subpicture_t *ParseText( decoder_t *p_dec, block_t *p_block )
322 {
323     decoder_sys_t *p_sys = p_dec->p_sys;
324     subpicture_t *p_spu = NULL;
325     char *psz_subtitle = NULL;
326     video_format_t fmt;
327
328     /* We cannot display a subpicture with no date */
329     if( p_block->i_pts == 0 )
330     {
331         msg_Warn( p_dec, "subtitle without a date" );
332         return NULL;
333     }
334
335     /* Check validity of packet data */
336     /* An "empty" line containing only \0 can be used to force
337        and ephemer picture from the screen */
338     if( p_block->i_buffer < 1 )
339     {
340         msg_Warn( p_dec, "no subtitle data" );
341         return NULL;
342     }
343
344     /* Should be resiliant against bad subtitles */
345     psz_subtitle = strndup( (const char *)p_block->p_buffer,
346                             p_block->i_buffer );
347     if( psz_subtitle == NULL )
348         return NULL;
349
350     if( p_sys->iconv_handle == (vlc_iconv_t)-1 )
351     {
352         if (EnsureUTF8( psz_subtitle ) == NULL)
353         {
354             msg_Err( p_dec, _("failed to convert subtitle encoding.\n"
355                      "Try manually setting a character-encoding "
356                      "before you open the file.") );
357         }
358     }
359     else
360     {
361
362         if( p_sys->b_autodetect_utf8 )
363         {
364             if( IsUTF8( psz_subtitle ) == NULL )
365             {
366                 msg_Dbg( p_dec, "invalid UTF-8 sequence: "
367                          "disabling UTF-8 subtitles autodetection" );
368                 p_sys->b_autodetect_utf8 = false;
369             }
370         }
371
372         if( !p_sys->b_autodetect_utf8 )
373         {
374             size_t inbytes_left = strlen( psz_subtitle );
375             size_t outbytes_left = 6 * inbytes_left;
376             char *psz_new_subtitle = malloc( outbytes_left + 1 );
377             char *psz_convert_buffer_out = psz_new_subtitle;
378             const char *psz_convert_buffer_in = psz_subtitle;
379
380             size_t ret = vlc_iconv( p_sys->iconv_handle,
381                                     &psz_convert_buffer_in, &inbytes_left,
382                                     &psz_convert_buffer_out, &outbytes_left );
383
384             *psz_convert_buffer_out++ = '\0';
385             free( psz_subtitle );
386
387             if( ( ret == (size_t)(-1) ) || inbytes_left )
388             {
389                 free( psz_new_subtitle );
390                 msg_Err( p_dec, _("failed to convert subtitle encoding.\n"
391                         "Try manually setting a character-encoding "
392                                 "before you open the file.") );
393                 return NULL;
394             }
395
396             psz_subtitle = realloc( psz_new_subtitle,
397                                     psz_convert_buffer_out - psz_new_subtitle );
398         }
399     }
400
401     /* Create the subpicture unit */
402     p_spu = p_dec->pf_spu_buffer_new( p_dec );
403     if( !p_spu )
404     {
405         msg_Warn( p_dec, "can't get spu buffer" );
406         free( psz_subtitle );
407         return NULL;
408     }
409
410     p_spu->b_pausable = true;
411
412     /* Create a new subpicture region */
413     memset( &fmt, 0, sizeof(video_format_t) );
414     fmt.i_chroma = VLC_FOURCC('T','E','X','T');
415     fmt.i_aspect = 0;
416     fmt.i_width = fmt.i_height = 0;
417     fmt.i_x_offset = fmt.i_y_offset = 0;
418     p_spu->p_region = p_spu->pf_create_region( VLC_OBJECT(p_dec), &fmt );
419     if( !p_spu->p_region )
420     {
421         msg_Err( p_dec, "cannot allocate SPU region" );
422         free( psz_subtitle );
423         p_dec->pf_spu_buffer_del( p_dec, p_spu );
424         return NULL;
425     }
426
427     /* Decode and format the subpicture unit */
428     if( p_dec->fmt_in.i_codec != VLC_FOURCC('s','s','a',' ') )
429     {
430         /* Normal text subs, easy markup */
431         p_spu->p_region->i_align = SUBPICTURE_ALIGN_BOTTOM | p_sys->i_align;
432         p_spu->i_x = p_sys->i_align ? 20 : 0;
433         p_spu->i_y = 10;
434
435         /* Remove formatting from string */
436
437         p_spu->p_region->psz_text = StripTags( psz_subtitle );
438         if( var_CreateGetBool( p_dec, "subsdec-formatted" ) )
439         {
440             p_spu->p_region->psz_html = CreateHtmlSubtitle( psz_subtitle );
441         }
442
443         p_spu->i_start = p_block->i_pts;
444         p_spu->i_stop = p_block->i_pts + p_block->i_length;
445         p_spu->b_ephemer = (p_block->i_length == 0);
446         p_spu->b_absolute = false;
447     }
448     else
449     {
450         /* Decode SSA/USF strings */
451         if( p_dec->fmt_in.i_codec == VLC_FOURCC('s','s','a',' ') )
452             ParseSSAString( p_dec, psz_subtitle, p_spu );
453
454         p_spu->i_start = p_block->i_pts;
455         p_spu->i_stop = p_block->i_pts + p_block->i_length;
456         p_spu->b_ephemer = (p_block->i_length == 0);
457         p_spu->b_absolute = false;
458         p_spu->i_original_picture_width = p_sys->i_original_width;
459         p_spu->i_original_picture_height = p_sys->i_original_height;
460     }
461     free( psz_subtitle );
462
463     return p_spu;
464 }
465
466 char* GotoNextLine( char *psz_text )
467 {
468     char *p_newline = psz_text;
469
470     while( p_newline[0] != '\0' )
471     {
472         if( p_newline[0] == '\n' || p_newline[0] == '\r' )
473         {
474             p_newline++;
475             while( p_newline[0] == '\n' || p_newline[0] == '\r' )
476                 p_newline++;
477             break;
478         }
479         else p_newline++;
480     }
481     return p_newline;
482 }
483
484 /* Function now handles tags with attribute values, and tries
485  * to deal with &' commands too. It no longer modifies the string
486  * in place, so that the original text can be reused
487  */
488 static char *StripTags( char *psz_subtitle )
489 {
490     char *psz_text_start;
491     char *psz_text;
492
493     psz_text = psz_text_start = malloc( strlen( psz_subtitle ) + 1 );
494     if( !psz_text_start )
495         return NULL;
496
497     while( *psz_subtitle )
498     {
499         if( *psz_subtitle == '<' )
500         {
501             if( strncasecmp( psz_subtitle, "<br/>", 5 ) == 0 )
502                 *psz_text++ = '\n';
503
504             psz_subtitle += strcspn( psz_subtitle, ">" );
505         }
506         else if( *psz_subtitle == '&' )
507         {
508             if( !strncasecmp( psz_subtitle, "&lt;", 4 ))
509             {
510                 *psz_text++ = '<';
511                 psz_subtitle += strcspn( psz_subtitle, ";" );
512             }
513             else if( !strncasecmp( psz_subtitle, "&gt;", 4 ))
514             {
515                 *psz_text++ = '>';
516                 psz_subtitle += strcspn( psz_subtitle, ";" );
517             }
518             else if( !strncasecmp( psz_subtitle, "&amp;", 5 ))
519             {
520                 *psz_text++ = '&';
521                 psz_subtitle += strcspn( psz_subtitle, ";" );
522             }
523             else if( !strncasecmp( psz_subtitle, "&quot;", 6 ))
524             {
525                 *psz_text++ = '\"';
526                 psz_subtitle += strcspn( psz_subtitle, ";" );
527             }
528             else
529             {
530                 /* Assume it is just a normal ampersand */
531                 *psz_text++ = '&';
532             }
533         }
534         else
535         {
536             *psz_text++ = *psz_subtitle;
537         }
538
539         psz_subtitle++;
540     }
541     *psz_text = '\0';
542     psz_text_start = realloc( psz_text_start, strlen( psz_text_start ) + 1 );
543
544     return psz_text_start;
545 }
546
547 /* Try to respect any style tags present in the subtitle string. The main
548  * problem here is a lack of adequate specs for the subtitle formats.
549  * SSA/ASS and USF are both detail spec'ed -- but they are handled elsewhere.
550  * SAMI has a detailed spec, but extensive rework is needed in the demux
551  * code to prevent all this style information being excised, as it presently
552  * does.
553  * That leaves the others - none of which were (I guess) originally intended
554  * to be carrying style information. Over time people have used them that way.
555  * In the absence of specifications from which to work, the tags supported
556  * have been restricted to the simple set permitted by the USF DTD, ie. :
557  *  Basic: <br>, <i>, <b>, <u>
558  *  Extended: <font>
559  *    Attributes: face
560  *                family
561  *                size
562  *                color
563  *                outline-color
564  *                shadow-color
565  *                outline-level
566  *                shadow-level
567  *                back-color
568  *                alpha
569  * There is also the further restriction that the subtitle be well-formed
570  * as an XML entity, ie. the HTML sentence:
571  *        <b><i>Bold and Italics</b></i>
572  * doesn't qualify because the tags aren't nested one inside the other.
573  * <text> tags are automatically added to the output to ensure
574  * well-formedness.
575  * If the text doesn't qualify for any reason, a NULL string is
576  * returned, and the rendering engine will fall back to the
577  * plain text version of the subtitle.
578  */
579 static char *CreateHtmlSubtitle( char *psz_subtitle )
580 {
581     char   *psz_tag = malloc( ( strlen( psz_subtitle ) / 3 ) + 1 );
582     if( !psz_tag ) return NULL;
583     size_t  i_buf_size     = strlen( psz_subtitle ) + 100;
584     char   *psz_html_start = malloc( i_buf_size );
585
586     psz_tag[ 0 ] = '\0';
587
588     if( psz_html_start == NULL )
589     {
590         free( psz_tag );
591         return NULL;
592     }
593     
594     char *psz_html = psz_html_start;
595
596     strcpy( psz_html, "<text>" );
597     psz_html += 6;
598
599     while( *psz_subtitle )
600     {
601         if( *psz_subtitle == '\n' )
602         {
603             strcpy( psz_html, "<br/>" );
604             psz_html += 5;
605             psz_subtitle++;
606         }
607         else if( *psz_subtitle == '<' )
608         {
609             if( !strncasecmp( psz_subtitle, "<br/>", 5 ))
610             {
611                 strcpy( psz_html, "<br/>" );
612                 psz_html += 5;
613                 psz_subtitle += 5;
614             }
615             else if( !strncasecmp( psz_subtitle, "<b>", 3 ) )
616             {
617                 strcpy( psz_html, "<b>" );
618                 strcat( psz_tag, "b" );
619                 psz_html += 3;
620                 psz_subtitle += 3;
621             }
622             else if( !strncasecmp( psz_subtitle, "<i>", 3 ) )
623             {
624                 strcpy( psz_html, "<i>" );
625                 strcat( psz_tag, "i" );
626                 psz_html += 3;
627                 psz_subtitle += 3;
628             }
629             else if( !strncasecmp( psz_subtitle, "<u>", 3 ) )
630             {
631                 strcpy( psz_html, "<u>" );
632                 strcat( psz_tag, "u" );
633                 psz_html += 3;
634                 psz_subtitle += 3;
635             }
636             else if( !strncasecmp( psz_subtitle, "<font ", 6 ))
637             {
638                 const char *psz_attribs[] = { "face=\"", "family=\"", "size=\"",
639                         "color=\"", "outline-color=\"", "shadow-color=\"",
640                         "outline-level=\"", "shadow-level=\"", "back-color=\"",
641                         "alpha=\"", NULL };
642
643                 strcpy( psz_html, "<font " );
644                 strcat( psz_tag, "f" );
645                 psz_html += 6;
646                 psz_subtitle += 6;
647
648                 while( *psz_subtitle != '>' )
649                 {
650                     int  k;
651
652                     for( k=0; psz_attribs[ k ]; k++ )
653                     {
654                         int i_len = strlen( psz_attribs[ k ] );
655
656                         if( !strncasecmp( psz_subtitle, psz_attribs[k], i_len ))
657                         {
658                             i_len += strcspn( psz_subtitle + i_len, "\"" ) + 1;
659
660                             strncpy( psz_html, psz_subtitle, i_len );
661                             psz_html += i_len;
662                             psz_subtitle += i_len;
663                             break;
664                         }
665                     }
666                     if( psz_attribs[ k ] == NULL )
667                     {
668                         /* Jump over unrecognised tag */
669                         int i_len = strcspn( psz_subtitle, "\"" ) + 1;
670
671                         i_len += strcspn( psz_subtitle + i_len, "\"" ) + 1;
672                         psz_subtitle += i_len;
673                     }
674                     while (*psz_subtitle == ' ')
675                         *psz_html++ = *psz_subtitle++;
676                 }
677                 *psz_html++ = *psz_subtitle++;
678             }
679             else if( !strncmp( psz_subtitle, "</", 2 ))
680             {
681                 bool   b_match     = false;
682                 int    i_len       = strlen( psz_tag ) - 1;
683                 char  *psz_lastTag = NULL;
684
685                 if( i_len >= 0 )
686                 {
687                     psz_lastTag = psz_tag + i_len;
688                     i_len = 0;
689
690                     switch( *psz_lastTag )
691                     {
692                     case 'b':
693                         b_match = !strncasecmp( psz_subtitle, "</b>", 4 );
694                         i_len   = 4;
695                         break;
696                     case 'i':
697                         b_match = !strncasecmp( psz_subtitle, "</i>", 4 );
698                         i_len   = 4;
699                         break;
700                     case 'u':
701                         b_match = !strncasecmp( psz_subtitle, "</u>", 4 );
702                         i_len   = 4;
703                         break;
704                     case 'f':
705                         b_match = !strncasecmp( psz_subtitle, "</font>", 7 );
706                         i_len   = 7;
707                         break;
708                     }
709                 }
710                 if( ! b_match )
711                 {
712                     /* Not well formed -- kill everything */
713                     free( psz_html_start );
714                     psz_html_start = NULL;
715                     break;
716                 }
717                 *psz_lastTag = '\0';
718                 strncpy( psz_html, psz_subtitle, i_len );
719                 psz_html += i_len;
720                 psz_subtitle += i_len;
721             }
722             else
723             {
724                 psz_subtitle += strcspn( psz_subtitle, ">" );
725             }
726         }
727         else if( *psz_subtitle == '&' )
728         {
729             if( !strncasecmp( psz_subtitle, "&lt;", 4 ))
730             {
731                 strcpy( psz_html, "&lt;" );
732                 psz_html += 4;
733                 psz_subtitle += 4;
734             }
735             else if( !strncasecmp( psz_subtitle, "&gt;", 4 ))
736             {
737                 strcpy( psz_html, "&gt;" );
738                 psz_html += 4;
739                 psz_subtitle += 4;
740             }
741             else if( !strncasecmp( psz_subtitle, "&amp;", 5 ))
742             {
743                 strcpy( psz_html, "&amp;" );
744                 psz_html += 5;
745                 psz_subtitle += 5;
746             }
747             else
748             {
749                 strcpy( psz_html, "&amp;" );
750                 psz_html += 5;
751                 psz_subtitle++;
752             }
753         }
754         else
755         {
756             *psz_html = *psz_subtitle;
757             if( psz_html > psz_html_start )
758             {
759                 /* Check for double whitespace */
760                 if((( *psz_html == ' ' ) ||
761                     ( *psz_html == '\t' )) &&
762                    (( *(psz_html-1) == ' ' ) ||
763                     ( *(psz_html-1) == '\t' )))
764                 {
765                     strcpy( psz_html, NO_BREAKING_SPACE );
766                     psz_html += strlen( NO_BREAKING_SPACE ) - 1;
767                 }
768             }
769             psz_html++;
770             psz_subtitle++;
771         }
772
773         if( ( size_t )( psz_html - psz_html_start ) > i_buf_size - 10 )
774         {
775             int i_len = psz_html - psz_html_start;
776
777             i_buf_size += 100;
778             psz_html_start = realloc( psz_html_start, i_buf_size );
779             psz_html = psz_html_start + i_len;
780             *psz_html = '\0';
781         }
782     }
783     strcpy( psz_html, "</text>" );
784     psz_html += 7;
785
786     if( psz_tag[ 0 ] != '\0' )
787     {
788         /* Not well formed -- kill everything */
789         free( psz_html_start );
790         psz_html_start = NULL;
791     }
792     else if( psz_html_start )
793     {
794         /* Shrink the memory requirements */
795         psz_html_start = realloc( psz_html_start,  psz_html - psz_html_start + 1 );
796     }
797     free( psz_tag );
798     return psz_html_start;
799 }