Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / webvttdec.c
1 /*
2 * Copyright (c) 2012 Clément Bœsch
3 *
4 * This file is part of FFmpeg.
5 *
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.
10 *
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.
15 *
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
19 */
20
21 /**
22 * @file
23 * WebVTT subtitle decoder
24 * @see http://dev.w3.org/html5/webvtt/
25 * @todo need to support extended markups and cue settings
26 */
27
28 #include "avcodec.h"
29 #include "ass.h"
30 #include "libavutil/bprint.h"
31
32 static const struct {
33 const char *from;
34 const char *to;
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
40 };
41
42 static int webvtt_event_to_ass(AVBPrint *buf, const char *p)
43 {
44 int i, skip = 0;
45
46 while (*p) {
47
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);
53 p += len;
54 break;
55 }
56 }
57 if (!*p)
58 break;
59
60 if (*p == '<')
61 skip = 1;
62 else if (*p == '>')
63 skip = 0;
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);
68 p++;
69 }
70 return 0;
71 }
72
73 static int webvtt_decode_frame(AVCodecContext *avctx,
74 void *data, int *got_sub_ptr, AVPacket *avpkt)
75 {
76 int ret = 0;
77 AVSubtitle *sub = data;
78 const char *ptr = avpkt->data;
79 AVBPrint buf;
80
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);
87 }
88 av_bprint_finalize(&buf, NULL);
89 if (ret < 0)
90 return ret;
91 *got_sub_ptr = sub->num_rects > 0;
92 return avpkt->size;
93 }
94
95 AVCodec ff_webvtt_decoder = {
96 .name = "webvtt",
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,
102 };