/src/vlc/modules/codec/webvtt/webvtt.c

Source
/*****************************************************************************
 * webvtt.c: WEBVTT shared code
 *****************************************************************************
 * Copyright (C) 2017 VideoLabs, VLC authors and VideoLAN
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_charset.h>
#include <vlc_plugin.h>

#include "webvtt.h"

#include <ctype.h>
#include <assert.h>

/*****************************************************************************
 * Modules descriptor.
 *****************************************************************************/

vlc_module_begin ()
    set_capability( "spu decoder", 10 )
    set_shortname( N_("WEBVTT decoder"))
    set_description( N_("WEBVTT subtitles decoder") )
    set_callbacks( webvtt_OpenDecoder, webvtt_CloseDecoder )
    set_subcategory( SUBCAT_INPUT_SCODEC )
    add_submodule()
        set_shortname( "WEBVTT" )
        set_description( N_("WEBVTT subtitles parser") )
        set_capability( "demux", 11 )
        set_subcategory( SUBCAT_INPUT_DEMUX )
        set_callbacks( webvtt_OpenDemux, webvtt_CloseDemux )
        add_shortcut( "webvtt" )
    add_submodule()
        set_shortname( "WEBVTT" )
        set_description( N_("WEBVTT subtitles parser") )
        set_capability( "demux", 0 )
        set_subcategory( SUBCAT_INPUT_DEMUX )
        set_callbacks( webvtt_OpenDemuxStream, webvtt_CloseDemux )
        add_shortcut( "webvttstream" )
#ifdef ENABLE_SOUT
    add_submodule()
        set_description( "WEBVTT text encoder" )
        set_capability( "spu encoder", 101 )
        set_subcategory( SUBCAT_INPUT_SCODEC )
        set_callback( webvtt_OpenEncoder )
    add_submodule()
        set_description( N_("Raw WebVTT muxer") )
        set_capability( "sout mux", 0 )
        set_subcategory( SUBCAT_SOUT_MUX )
        add_shortcut( "webvtt", "rawvtt" )
        set_callbacks( webvtt_OpenMuxer, webvtt_CloseMuxer )
#endif
vlc_module_end ()

struct webvtt_text_parser_t
{
    enum
    {
        WEBVTT_SECTION_UNDEFINED = WEBVTT_HEADER_STYLE - 1,
        WEBVTT_SECTION_STYLE = WEBVTT_HEADER_STYLE,
        WEBVTT_SECTION_REGION = WEBVTT_HEADER_REGION,
        WEBVTT_SECTION_NOTE,
        WEBVTT_SECTION_CUES,
    } section;
    char * reads[3];

    void * priv;
    webvtt_cue_t *(*pf_get_cue)( void * );
    void (*pf_cue_done)( void *, webvtt_cue_t * );
    void (*pf_header)( void *, enum webvtt_header_line_e, bool, const char * );

    webvtt_cue_t *p_cue;
};

static vlc_tick_t MakeTime( int t[4] )
{
    return vlc_tick_from_sec( t[0] * 3600 + t[1] * 60 + t[2] ) +
           VLC_TICK_FROM_MS(t[3]);
}

bool webvtt_scan_time( const char *psz, vlc_tick_t *p_time )
{
    int t[4];
    if( sscanf( psz, "%2d:%2d.%3d",
                      &t[1], &t[2], &t[3] ) == 3 )
    {
        t[0] = 0;
        *p_time = MakeTime( t );
        return true;
    }
    else if( sscanf( psz, "%d:%2d:%2d.%3d",
                          &t[0], &t[1], &t[2], &t[3] ) == 4 )
    {
        *p_time = MakeTime( t );
        return true;
    }
    else return false;
}

static bool KeywordMatch( const char *psz, const char *keyword )
{
    const size_t i_len = strlen(keyword);
    return( !strncmp( keyword, psz, i_len ) && (!psz[i_len] || isspace(psz[i_len])) );
}

/*

*/

webvtt_text_parser_t * webvtt_text_parser_New( void *priv,
                    webvtt_cue_t *(*pf_get_cue)( void * ),
                    void (*pf_cue_done)( void *, webvtt_cue_t * ),
                    void (*pf_header)( void *, enum webvtt_header_line_e, bool, const char * ) )
{
    webvtt_text_parser_t *p = malloc(sizeof(*p));
    if( p )
    {
        p->section = WEBVTT_SECTION_UNDEFINED;
        for( int i=0; i<3; i++ )
            p->reads[i] = NULL;
        p->p_cue = NULL;
        p->priv = priv;
        p->pf_cue_done = pf_cue_done;
        p->pf_get_cue = pf_get_cue;
        p->pf_header = pf_header;
    }
    return p;
}

void webvtt_text_parser_Delete( webvtt_text_parser_t *p )
{
    for( int i=0; i<3; i++ )
        free( p->reads[i] );
    free( p );
}

static void forward_line( webvtt_text_parser_t *p, const char *psz_line, bool b_new )
{
    if( p->pf_header )
        p->pf_header( p->priv, (enum webvtt_header_line_e)p->section,
                      b_new, psz_line );
}

void webvtt_text_parser_Feed( webvtt_text_parser_t *p, char *psz_line )
{
    if( psz_line == NULL )
    {
        if( p->p_cue )
        {
            if( p->pf_cue_done )
                p->pf_cue_done( p->priv, p->p_cue );
            p->p_cue = NULL;
        }
        return;
    }

    free(p->reads[0]);
    p->reads[0] = p->reads[1];
    p->reads[1] = p->reads[2];
    p->reads[2] = psz_line;

    /* Lookup keywords */
    if( unlikely(p->section == WEBVTT_SECTION_UNDEFINED) )
    {
        if( KeywordMatch( psz_line, "\xEF\xBB\xBFWEBVTT" ) ||
            KeywordMatch( psz_line, "WEBVTT" )  )
        {
            p->section = WEBVTT_SECTION_UNDEFINED;
            if( p->p_cue )
            {
                if( p->pf_cue_done )
                    p->pf_cue_done( p->priv, p->p_cue );
                p->p_cue = NULL;
            }
            return;
        }
        else if( KeywordMatch( psz_line, "STYLE" ) )
        {
            p->section = WEBVTT_SECTION_STYLE;
            forward_line( p, psz_line, true );
            return;
        }
        else if( KeywordMatch( psz_line, "REGION" ) )
        {
            p->section = WEBVTT_SECTION_REGION;
            forward_line( p, psz_line, true );
            return;
        }
        else if( KeywordMatch( psz_line, "NOTE" ) )
        {
            p->section = WEBVTT_SECTION_NOTE;
            return;
        }
        else if( psz_line[0] != 0 )
        {
            p->section = WEBVTT_SECTION_CUES;
        }
    }

    if( likely(p->section == WEBVTT_SECTION_CUES) )
    {
        if( p->p_cue )
        {
            if( psz_line[0] == 0 )
            {
                if( p->p_cue )
                {
                    if( p->pf_cue_done )
                        p->pf_cue_done( p->priv, p->p_cue );
                    p->p_cue = NULL;
                }
            }
            else
            {
                char *psz_merged;
                if( -1 < asprintf( &psz_merged, "%s\n%s", p->p_cue->psz_text, psz_line ) )
                {
                    free( p->p_cue->psz_text );
                    p->p_cue->psz_text = psz_merged;
                }
                return;
            }
        }

        if( p->reads[1] == NULL )
            return;

        const char *psz_split = strstr( p->reads[1], " --> " );
        if( psz_split )
        {
            vlc_tick_t i_start, i_stop;

            if( webvtt_scan_time( p->reads[1], &i_start ) &&
                webvtt_scan_time( psz_split + 5,  &i_stop ) && i_start <= i_stop )
            {
                const char *psz_attrs = strchr( psz_split + 5 + 5, ' ' );
                p->p_cue = ( p->pf_get_cue ) ? p->pf_get_cue( p->priv ) : NULL;
                if( p->p_cue )
                {
                    p->p_cue->psz_attrs = ( psz_attrs ) ? strdup( psz_attrs ) : NULL;
                    p->p_cue->psz_id = p->reads[0];
                    p->reads[0] = NULL;
                    p->p_cue->psz_text = p->reads[2];
                    p->reads[2] = NULL;
                    p->p_cue->i_start = i_start;
                    p->p_cue->i_stop = i_stop;
                }
            }
        }
    }
    else if( p->section == WEBVTT_SECTION_STYLE )
    {
        forward_line( p, psz_line, false );
        if( psz_line[0] == 0 )
            p->section = WEBVTT_SECTION_UNDEFINED;
    }
    else if( p->section == WEBVTT_SECTION_REGION )
    {
        forward_line( p, psz_line, false );
        if( psz_line[0] == 0 ) /* End of region declaration */
            p->section = WEBVTT_SECTION_UNDEFINED;
    }
    else if( p->section == WEBVTT_SECTION_NOTE )
    {
        if( psz_line[0] == 0 )
            p->section = WEBVTT_SECTION_UNDEFINED;
    }
}

Coverage Report

Created: 2025-11-24 06:20

Line	Count	Source
1		/*****************************************************************************
2		* webvtt.c: WEBVTT shared code
3		*****************************************************************************
4		* Copyright (C) 2017 VideoLabs, VLC authors and VideoLAN
5		*
6		* This program is free software; you can redistribute it and/or modify it
7		* under the terms of the GNU Lesser General Public License as published by
8		* the Free Software Foundation; either version 2.1 of the License, or
9		* (at your option) any later version.
10		*
11		* This program is distributed in the hope that it will be useful,
12		* but WITHOUT ANY WARRANTY; without even the implied warranty of
13		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14		* GNU Lesser General Public License for more details.
15		*
16		* You should have received a copy of the GNU Lesser General Public License
17		* along with this program; if not, write to the Free Software Foundation,
18		* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
19		*****************************************************************************/
20
21		#ifdef HAVE_CONFIG_H
22		# include "config.h"
23		#endif
24
25		#include <vlc_common.h>
26		#include <vlc_charset.h>
27		#include <vlc_plugin.h>
28
29		#include "webvtt.h"
30
31		#include <ctype.h>
32		#include <assert.h>
33
34		/*****************************************************************************
35		* Modules descriptor.
36		*****************************************************************************/
37
38	108	vlc_module_begin ()
39	54	set_capability( "spu decoder", 10 )
40	54	set_shortname( N_("WEBVTT decoder"))
41	54	set_description( N_("WEBVTT subtitles decoder") )
42	108	set_callbacks( webvtt_OpenDecoder, webvtt_CloseDecoder )
43	54	set_subcategory( SUBCAT_INPUT_SCODEC )
44	54	add_submodule()
45	54	set_shortname( "WEBVTT" )
46	54	set_description( N_("WEBVTT subtitles parser") )
47	54	set_capability( "demux", 11 )
48	54	set_subcategory( SUBCAT_INPUT_DEMUX )
49	54	set_callbacks( webvtt_OpenDemux, webvtt_CloseDemux )
50	54	add_shortcut( "webvtt" )
51	54	add_submodule()
52	54	set_shortname( "WEBVTT" )
53	54	set_description( N_("WEBVTT subtitles parser") )
54	54	set_capability( "demux", 0 )
55	54	set_subcategory( SUBCAT_INPUT_DEMUX )
56	54	set_callbacks( webvtt_OpenDemuxStream, webvtt_CloseDemux )
57	54	add_shortcut( "webvttstream" )
58	54	#ifdef ENABLE_SOUT
59	54	add_submodule()
60	54	set_description( "WEBVTT text encoder" )
61	54	set_capability( "spu encoder", 101 )
62	54	set_subcategory( SUBCAT_INPUT_SCODEC )
63	54	set_callback( webvtt_OpenEncoder )
64	54	add_submodule()
65	54	set_description( N_("Raw WebVTT muxer") )
66	54	set_capability( "sout mux", 0 )
67	54	set_subcategory( SUBCAT_SOUT_MUX )
68	54	add_shortcut( "webvtt", "rawvtt" )
69	108	set_callbacks( webvtt_OpenMuxer, webvtt_CloseMuxer )
70	54	#endif
71	54	vlc_module_end ()
72
73		struct webvtt_text_parser_t
74		{
75		enum
76		{
77		WEBVTT_SECTION_UNDEFINED = WEBVTT_HEADER_STYLE - 1,
78		WEBVTT_SECTION_STYLE = WEBVTT_HEADER_STYLE,
79		WEBVTT_SECTION_REGION = WEBVTT_HEADER_REGION,
80		WEBVTT_SECTION_NOTE,
81		WEBVTT_SECTION_CUES,
82		} section;
83		char * reads[3];
84
85		void * priv;
86		webvtt_cue_t (pf_get_cue)( void * );
87		void (pf_cue_done)( void , webvtt_cue_t * );
88		void (pf_header)( void , enum webvtt_header_line_e, bool, const char * );
89
90		webvtt_cue_t *p_cue;
91		};
92
93		static vlc_tick_t MakeTime( int t[4] )
94	286k	{
95	286k	return vlc_tick_from_sec( t[0] * 3600 + t[1] * 60 + t[2] ) +
96	286k	VLC_TICK_FROM_MS(t[3]);
97	286k	}
98
99		bool webvtt_scan_time( const char psz, vlc_tick_t p_time )
100	321k	{
101	321k	int t[4];
102	321k	if( sscanf( psz, "%2d:%2d.%3d",
103	321k	&t[1], &t[2], &t[3] ) == 3 )
104	49.6k	{
105	49.6k	t[0] = 0;
106	49.6k	*p_time = MakeTime( t );
107	49.6k	return true;
108	49.6k	}
109	271k	else if( sscanf( psz, "%d:%2d:%2d.%3d",
110	271k	&t[0], &t[1], &t[2], &t[3] ) == 4 )
111	237k	{
112	237k	*p_time = MakeTime( t );
113	237k	return true;
114	237k	}
115	34.6k	else return false;
116	321k	}
117
118		static bool KeywordMatch( const char psz, const char keyword )
119	261k	{
120	261k	const size_t i_len = strlen(keyword);
121	261k	return( !strncmp( keyword, psz, i_len ) && (!psz[i_len] \|\| isspace(psz[i_len])) );
122	261k	}
123
124		/*
125
126		*/
127
128		webvtt_text_parser_t * webvtt_text_parser_New( void *priv,
129		webvtt_cue_t (pf_get_cue)( void * ),
130		void (pf_cue_done)( void , webvtt_cue_t * ),
131		void (pf_header)( void , enum webvtt_header_line_e, bool, const char * ) )
132	16.9k	{
133	16.9k	webvtt_text_parser_t p = malloc(sizeof(p));
134	16.9k	if( p )
135	16.9k	{
136	16.9k	p->section = WEBVTT_SECTION_UNDEFINED;
137	67.9k	for( int i=0; i<3; i++ )
138	50.9k	p->reads[i] = NULL;
139	16.9k	p->p_cue = NULL;
140	16.9k	p->priv = priv;
141	16.9k	p->pf_cue_done = pf_cue_done;
142	16.9k	p->pf_get_cue = pf_get_cue;
143	16.9k	p->pf_header = pf_header;
144	16.9k	}
145	16.9k	return p;
146	16.9k	}
147
148		void webvtt_text_parser_Delete( webvtt_text_parser_t *p )
149	16.9k	{
150	67.9k	for( int i=0; i<3; i++ )
151	50.9k	free( p->reads[i] );
152	16.9k	free( p );
153	16.9k	}
154
155		static void forward_line( webvtt_text_parser_t p, const char psz_line, bool b_new )
156	281k	{
157	281k	if( p->pf_header )
158	281k	p->pf_header( p->priv, (enum webvtt_header_line_e)p->section,
159	281k	b_new, psz_line );
160	281k	}
161
162		void webvtt_text_parser_Feed( webvtt_text_parser_t p, char psz_line )
163	1.91M	{
164	1.91M	if( psz_line == NULL )
165	8.49k	{
166	8.49k	if( p->p_cue )
167	4.29k	{
168	4.29k	if( p->pf_cue_done )
169	4.29k	p->pf_cue_done( p->priv, p->p_cue );
170	4.29k	p->p_cue = NULL;
171	4.29k	}
172	8.49k	return;
173	8.49k	}
174
175	1.91M	free(p->reads[0]);
176	1.91M	p->reads[0] = p->reads[1];
177	1.91M	p->reads[1] = p->reads[2];
178	1.91M	p->reads[2] = psz_line;
179
180		/* Lookup keywords */
181	1.91M	if( unlikely(p->section == WEBVTT_SECTION_UNDEFINED) )
182	71.4k	{
183	71.4k	if( KeywordMatch( psz_line, "\xEF\xBB\xBFWEBVTT" ) \|\|
184	68.4k	KeywordMatch( psz_line, "WEBVTT" ) )
185	13.0k	{
186	13.0k	p->section = WEBVTT_SECTION_UNDEFINED;
187	13.0k	if( p->p_cue )
188	0	{
189	0	if( p->pf_cue_done )
190	0	p->pf_cue_done( p->priv, p->p_cue );
191	0	p->p_cue = NULL;
192	0	}
193	13.0k	return;
194	13.0k	}
195	58.4k	else if( KeywordMatch( psz_line, "STYLE" ) )
196	22.5k	{
197	22.5k	p->section = WEBVTT_SECTION_STYLE;
198	22.5k	forward_line( p, psz_line, true );
199	22.5k	return;
200	22.5k	}
201	35.8k	else if( KeywordMatch( psz_line, "REGION" ) )
202	8.24k	{
203	8.24k	p->section = WEBVTT_SECTION_REGION;
204	8.24k	forward_line( p, psz_line, true );
205	8.24k	return;
206	8.24k	}
207	27.6k	else if( KeywordMatch( psz_line, "NOTE" ) )
208	217	{
209	217	p->section = WEBVTT_SECTION_NOTE;
210	217	return;
211	217	}
212	27.4k	else if( psz_line[0] != 0 )
213	6.10k	{
214	6.10k	p->section = WEBVTT_SECTION_CUES;
215	6.10k	}
216	71.4k	}
217
218	1.86M	if( likely(p->section == WEBVTT_SECTION_CUES) )
219	1.59M	{
220	1.59M	if( p->p_cue )
221	213k	{
222	213k	if( psz_line[0] == 0 )
223	107k	{
224	107k	if( p->p_cue )
225	107k	{
226	107k	if( p->pf_cue_done )
227	107k	p->pf_cue_done( p->priv, p->p_cue );
228	107k	p->p_cue = NULL;
229	107k	}
230	107k	}
231	105k	else
232	105k	{
233	105k	char *psz_merged;
234	105k	if( -1 < asprintf( &psz_merged, "%s\n%s", p->p_cue->psz_text, psz_line ) )
235	105k	{
236	105k	free( p->p_cue->psz_text );
237	105k	p->p_cue->psz_text = psz_merged;
238	105k	}
239	105k	return;
240	105k	}
241	213k	}
242
243	1.48M	if( p->reads[1] == NULL )
244	46.9k	return;
245
246	1.44M	const char *psz_split = strstr( p->reads[1], " --> " );
247	1.44M	if( psz_split )
248	125k	{
249	125k	vlc_tick_t i_start, i_stop;
250
251	125k	if( webvtt_scan_time( p->reads[1], &i_start ) &&
252	120k	webvtt_scan_time( psz_split + 5, &i_stop ) && i_start <= i_stop )
253	112k	{
254	112k	const char *psz_attrs = strchr( psz_split + 5 + 5, ' ' );
255	112k	p->p_cue = ( p->pf_get_cue ) ? p->pf_get_cue( p->priv ) : NULL;
256	112k	if( p->p_cue )
257	112k	{
258	112k	p->p_cue->psz_attrs = ( psz_attrs ) ? strdup( psz_attrs ) : NULL;
259	112k	p->p_cue->psz_id = p->reads[0];
260	112k	p->reads[0] = NULL;
261	112k	p->p_cue->psz_text = p->reads[2];
262	112k	p->reads[2] = NULL;
263	112k	p->p_cue->i_start = i_start;
264	112k	p->p_cue->i_stop = i_stop;
265	112k	}
266	112k	}
267	125k	}
268	1.44M	}
269	272k	else if( p->section == WEBVTT_SECTION_STYLE )
270	199k	{
271	199k	forward_line( p, psz_line, false );
272	199k	if( psz_line[0] == 0 )
273	19.1k	p->section = WEBVTT_SECTION_UNDEFINED;
274	199k	}
275	73.7k	else if( p->section == WEBVTT_SECTION_REGION )
276	51.9k	{
277	51.9k	forward_line( p, psz_line, false );
278	51.9k	if( psz_line[0] == 0 ) /* End of region declaration */
279	7.00k	p->section = WEBVTT_SECTION_UNDEFINED;
280	51.9k	}
281	21.8k	else if( p->section == WEBVTT_SECTION_NOTE )
282	546	{
283	546	if( psz_line[0] == 0 )
284	208	p->section = WEBVTT_SECTION_UNDEFINED;
285	546	}
286	1.86M	}