/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( int32_t t[4] )
{
    return vlc_tick_from_sec( (int64_t)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 )
{
    int32_t t[4];
    if( sscanf( psz, "%2" SCNd32 ":%2" SCNd32 ".%3" SCNd32,
                      &t[1], &t[2], &t[3] ) == 3 )
    {
        t[0] = 0;
        if( t[1] < 0 || t[2] < 0 || t[3] < 0 )
            return false;

        *p_time = MakeTime( t );
        return true;
    }
    else if( sscanf( psz, "%" SCNd32 ":%2" SCNd32 ":%2" SCNd32 ".%3" SCNd32,
                          &t[0], &t[1], &t[2], &t[3] ) == 4 )
    {
        if( t[0] < 0 || t[1] < 0 || t[2] < 0 || t[3] < 0 )
            return false;

        *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: 2026-05-16 07:42

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	134	vlc_module_begin ()
39	67	set_capability( "spu decoder", 10 )
40	67	set_shortname( N_("WEBVTT decoder"))
41	67	set_description( N_("WEBVTT subtitles decoder") )
42	134	set_callbacks( webvtt_OpenDecoder, webvtt_CloseDecoder )
43	67	set_subcategory( SUBCAT_INPUT_SCODEC )
44	67	add_submodule()
45	67	set_shortname( "WEBVTT" )
46	67	set_description( N_("WEBVTT subtitles parser") )
47	67	set_capability( "demux", 11 )
48	67	set_subcategory( SUBCAT_INPUT_DEMUX )
49	67	set_callbacks( webvtt_OpenDemux, webvtt_CloseDemux )
50	67	add_shortcut( "webvtt" )
51	67	add_submodule()
52	67	set_shortname( "WEBVTT" )
53	67	set_description( N_("WEBVTT subtitles parser") )
54	67	set_capability( "demux", 0 )
55	67	set_subcategory( SUBCAT_INPUT_DEMUX )
56	67	set_callbacks( webvtt_OpenDemuxStream, webvtt_CloseDemux )
57	67	add_shortcut( "webvttstream" )
58	67	#ifdef ENABLE_SOUT
59	67	add_submodule()
60	67	set_description( "WEBVTT text encoder" )
61	67	set_capability( "spu encoder", 101 )
62	67	set_subcategory( SUBCAT_INPUT_SCODEC )
63	67	set_callback( webvtt_OpenEncoder )
64	67	add_submodule()
65	67	set_description( N_("Raw WebVTT muxer") )
66	67	set_capability( "sout mux", 0 )
67	67	set_subcategory( SUBCAT_SOUT_MUX )
68	67	add_shortcut( "webvtt", "rawvtt" )
69	134	set_callbacks( webvtt_OpenMuxer, webvtt_CloseMuxer )
70	67	#endif
71	67	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( int32_t t[4] )
94	862k	{
95	862k	return vlc_tick_from_sec( (int64_t)t[0] * 3600 + t[1] * 60 + t[2] ) +
96	862k	VLC_TICK_FROM_MS(t[3]);
97	862k	}
98
99		bool webvtt_scan_time( const char psz, vlc_tick_t p_time )
100	920k	{
101	920k	int32_t t[4];
102	920k	if( sscanf( psz, "%2" SCNd32 ":%2" SCNd32 ".%3" SCNd32,
103	920k	&t[1], &t[2], &t[3] ) == 3 )
104	82.9k	{
105	82.9k	t[0] = 0;
106	82.9k	if( t[1] < 0 \|\| t[2] < 0 \|\| t[3] < 0 )
107	606	return false;
108
109	82.3k	*p_time = MakeTime( t );
110	82.3k	return true;
111	82.9k	}
112	837k	else if( sscanf( psz, "%" SCNd32 ":%2" SCNd32 ":%2" SCNd32 ".%3" SCNd32,
113	837k	&t[0], &t[1], &t[2], &t[3] ) == 4 )
114	787k	{
115	787k	if( t[0] < 0 \|\| t[1] < 0 \|\| t[2] < 0 \|\| t[3] < 0 )
116	6.92k	return false;
117
118	780k	*p_time = MakeTime( t );
119	780k	return true;
120	787k	}
121	50.1k	else return false;
122	920k	}
123
124		static bool KeywordMatch( const char psz, const char keyword )
125	192k	{
126	192k	const size_t i_len = strlen(keyword);
127	192k	return( !strncmp( keyword, psz, i_len ) && (!psz[i_len] \|\| isspace(psz[i_len])) );
128	192k	}
129
130		/*
131
132		*/
133
134		webvtt_text_parser_t * webvtt_text_parser_New( void *priv,
135		webvtt_cue_t (pf_get_cue)( void * ),
136		void (pf_cue_done)( void , webvtt_cue_t * ),
137		void (pf_header)( void , enum webvtt_header_line_e, bool, const char * ) )
138	9.08k	{
139	9.08k	webvtt_text_parser_t p = malloc(sizeof(p));
140	9.08k	if( p )
141	9.08k	{
142	9.08k	p->section = WEBVTT_SECTION_UNDEFINED;
143	36.3k	for( int i=0; i<3; i++ )
144	27.2k	p->reads[i] = NULL;
145	9.08k	p->p_cue = NULL;
146	9.08k	p->priv = priv;
147	9.08k	p->pf_cue_done = pf_cue_done;
148	9.08k	p->pf_get_cue = pf_get_cue;
149	9.08k	p->pf_header = pf_header;
150	9.08k	}
151	9.08k	return p;
152	9.08k	}
153
154		void webvtt_text_parser_Delete( webvtt_text_parser_t *p )
155	9.08k	{
156	36.3k	for( int i=0; i<3; i++ )
157	27.2k	free( p->reads[i] );
158	9.08k	free( p );
159	9.08k	}
160
161		static void forward_line( webvtt_text_parser_t p, const char psz_line, bool b_new )
162	270k	{
163	270k	if( p->pf_header )
164	270k	p->pf_header( p->priv, (enum webvtt_header_line_e)p->section,
165	270k	b_new, psz_line );
166	270k	}
167
168		void webvtt_text_parser_Feed( webvtt_text_parser_t p, char psz_line )
169	2.58M	{
170	2.58M	if( psz_line == NULL )
171	4.54k	{
172	4.54k	if( p->p_cue )
173	2.12k	{
174	2.12k	if( p->pf_cue_done )
175	2.12k	p->pf_cue_done( p->priv, p->p_cue );
176	2.12k	p->p_cue = NULL;
177	2.12k	}
178	4.54k	return;
179	4.54k	}
180
181	2.57M	free(p->reads[0]);
182	2.57M	p->reads[0] = p->reads[1];
183	2.57M	p->reads[1] = p->reads[2];
184	2.57M	p->reads[2] = psz_line;
185
186		/* Lookup keywords */
187	2.57M	if( unlikely(p->section == WEBVTT_SECTION_UNDEFINED) )
188	52.6k	{
189	52.6k	if( KeywordMatch( psz_line, "\xEF\xBB\xBFWEBVTT" ) \|\|
190	50.2k	KeywordMatch( psz_line, "WEBVTT" ) )
191	8.05k	{
192	8.05k	p->section = WEBVTT_SECTION_UNDEFINED;
193	8.05k	if( p->p_cue )
194	0	{
195	0	if( p->pf_cue_done )
196	0	p->pf_cue_done( p->priv, p->p_cue );
197	0	p->p_cue = NULL;
198	0	}
199	8.05k	return;
200	8.05k	}
201	44.5k	else if( KeywordMatch( psz_line, "STYLE" ) )
202	19.0k	{
203	19.0k	p->section = WEBVTT_SECTION_STYLE;
204	19.0k	forward_line( p, psz_line, true );
205	19.0k	return;
206	19.0k	}
207	25.4k	else if( KeywordMatch( psz_line, "REGION" ) )
208	6.30k	{
209	6.30k	p->section = WEBVTT_SECTION_REGION;
210	6.30k	forward_line( p, psz_line, true );
211	6.30k	return;
212	6.30k	}
213	19.1k	else if( KeywordMatch( psz_line, "NOTE" ) )
214	191	{
215	191	p->section = WEBVTT_SECTION_NOTE;
216	191	return;
217	191	}
218	18.9k	else if( psz_line[0] != 0 )
219	3.85k	{
220	3.85k	p->section = WEBVTT_SECTION_CUES;
221	3.85k	}
222	52.6k	}
223
224	2.54M	if( likely(p->section == WEBVTT_SECTION_CUES) )
225	2.28M	{
226	2.28M	if( p->p_cue )
227	482k	{
228	482k	if( psz_line[0] == 0 )
229	382k	{
230	382k	if( p->p_cue )
231	382k	{
232	382k	if( p->pf_cue_done )
233	382k	p->pf_cue_done( p->priv, p->p_cue );
234	382k	p->p_cue = NULL;
235	382k	}
236	382k	}
237	99.9k	else
238	99.9k	{
239	99.9k	char *psz_merged;
240	99.9k	if( -1 < asprintf( &psz_merged, "%s\n%s", p->p_cue->psz_text, psz_line ) )
241	99.9k	{
242	99.9k	free( p->p_cue->psz_text );
243	99.9k	p->p_cue->psz_text = psz_merged;
244	99.9k	}
245	99.9k	return;
246	99.9k	}
247	482k	}
248
249	2.18M	if( p->reads[1] == NULL )
250	330k	return;
251
252	1.85M	const char *psz_split = strstr( p->reads[1], " --> " );
253	1.85M	if( psz_split )
254	437k	{
255	437k	vlc_tick_t i_start, i_stop;
256
257	437k	if( webvtt_scan_time( p->reads[1], &i_start ) &&
258	423k	webvtt_scan_time( psz_split + 5, &i_stop ) && i_start <= i_stop )
259	384k	{
260	384k	const char *psz_attrs = strchr( psz_split + 5 + 5, ' ' );
261	384k	p->p_cue = ( p->pf_get_cue ) ? p->pf_get_cue( p->priv ) : NULL;
262	384k	if( p->p_cue )
263	384k	{
264	384k	p->p_cue->psz_attrs = ( psz_attrs ) ? strdup( psz_attrs ) : NULL;
265	384k	p->p_cue->psz_id = p->reads[0];
266	384k	p->reads[0] = NULL;
267	384k	p->p_cue->psz_text = p->reads[2];
268	384k	p->reads[2] = NULL;
269	384k	p->p_cue->i_start = i_start;
270	384k	p->p_cue->i_stop = i_stop;
271	384k	}
272	384k	}
273	437k	}
274	1.85M	}
275	260k	else if( p->section == WEBVTT_SECTION_STYLE )
276	200k	{
277	200k	forward_line( p, psz_line, false );
278	200k	if( psz_line[0] == 0 )
279	17.9k	p->section = WEBVTT_SECTION_UNDEFINED;
280	200k	}
281	59.3k	else if( p->section == WEBVTT_SECTION_REGION )
282	43.7k	{
283	43.7k	forward_line( p, psz_line, false );
284	43.7k	if( psz_line[0] == 0 ) /* End of region declaration */
285	6.09k	p->section = WEBVTT_SECTION_UNDEFINED;
286	43.7k	}
287	15.6k	else if( p->section == WEBVTT_SECTION_NOTE )
288	475	{
289	475	if( psz_line[0] == 0 )
290	189	p->section = WEBVTT_SECTION_UNDEFINED;
291	475	}
292	2.54M	}