2 * Copyright (c) 2012 Clément Bœsch
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg 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 GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * WebVTT subtitle decoder
24 * @see http://dev.w3.org/html5/webvtt/
25 * @todo need to support extended markups and cue settings
30 #include "libavutil/bprint.h"
35 } webvtt_tag_replace
[] = {
36 {"<i>", "{\\i1}"}, {"</i>", "{\\i0}"},
37 {"<b>", "{\\b1}"}, {"</b>", "{\\b0}"},
38 {"<u>", "{\\u1}"}, {"</u>", "{\\u0}"},
39 {"{", "\\{"}, {"}", "\\}"}, // escape to avoid ASS markup conflicts
42 static int webvtt_event_to_ass(AVBPrint
*buf
, const char *p
)
48 for (i
= 0; i
< FF_ARRAY_ELEMS(webvtt_tag_replace
); i
++) {
49 const char *from
= webvtt_tag_replace
[i
].from
;
50 const size_t len
= strlen(from
);
51 if (!strncmp(p
, from
, len
)) {
52 av_bprintf(buf
, "%s", webvtt_tag_replace
[i
].to
);
64 else if (p
[0] == '\n' && p
[1])
65 av_bprintf(buf
, "\\N");
66 else if (!skip
&& *p
!= '\r')
67 av_bprint_chars(buf
, *p
, 1);
73 static int webvtt_decode_frame(AVCodecContext
*avctx
,
74 void *data
, int *got_sub_ptr
, AVPacket
*avpkt
)
77 AVSubtitle
*sub
= data
;
78 const char *ptr
= avpkt
->data
;
81 av_bprint_init(&buf
, 0, AV_BPRINT_SIZE_UNLIMITED
);
82 if (ptr
&& avpkt
->size
> 0 && !webvtt_event_to_ass(&buf
, ptr
)) {
83 int ts_start
= av_rescale_q(avpkt
->pts
, avctx
->time_base
, (AVRational
){1,100});
84 int ts_duration
= avpkt
->duration
!= -1 ?
85 av_rescale_q(avpkt
->duration
, avctx
->time_base
, (AVRational
){1,100}) : -1;
86 ret
= ff_ass_add_rect_bprint(sub
, &buf
, ts_start
, ts_duration
);
88 av_bprint_finalize(&buf
, NULL
);
91 *got_sub_ptr
= sub
->num_rects
> 0;
95 AVCodec ff_webvtt_decoder
= {
97 .long_name
= NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
98 .type
= AVMEDIA_TYPE_SUBTITLE
,
99 .id
= AV_CODEC_ID_WEBVTT
,
100 .decode
= webvtt_decode_frame
,
101 .init
= ff_ass_subtitle_header_default
,