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 demuxer
24 * @see http://dev.w3.org/html5/webvtt/
29 #include "subtitles.h"
30 #include "libavutil/bprint.h"
31 #include "libavutil/intreadwrite.h"
34 FFDemuxSubtitlesQueue q;
37 static int webvtt_probe(AVProbeData *p)
39 const uint8_t *ptr = p->buf;
41 if (AV_RB24(ptr) == 0xEFBBBF)
42 ptr += 3; /* skip UTF-8 BOM */
43 if (!strncmp(ptr, "WEBVTT", 6) &&
44 (!ptr[6] || strchr("\n\r\t ", ptr[6])))
45 return AVPROBE_SCORE_MAX;
49 static int64_t read_ts(const char *s)
52 if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600LL + mm*60LL + ss) * 1000LL + ms;
53 if (sscanf(s, "%u:%u.%u", &mm, &ss, &ms) == 3) return ( mm*60LL + ss) * 1000LL + ms;
54 return AV_NOPTS_VALUE;
57 static int webvtt_read_header(AVFormatContext *s)
59 WebVTTContext *webvtt = s->priv_data;
62 AVStream *st = avformat_new_stream(s, NULL);
65 return AVERROR(ENOMEM);
66 avpriv_set_pts_info(st, 64, 1, 1000);
67 st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
68 st->codec->codec_id = AV_CODEC_ID_WEBVTT;
70 av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
71 av_bprint_init(&cue, 0, AV_BPRINT_SIZE_UNLIMITED);
77 const char *p, *identifier, *settings;
78 int identifier_len, settings_len;
79 int64_t ts_start, ts_end;
81 ff_subtitles_read_chunk(s->pb, &cue);
86 p = identifier = cue.str;
87 pos = avio_tell(s->pb);
89 /* ignore header chunk */
90 if (!strncmp(p, "\xEF\xBB\xBFWEBVTT", 9) ||
91 !strncmp(p, "WEBVTT", 6))
94 /* optional cue identifier (can be a number like in SRT or some kind of
96 for (i = 0; p[i] && p[i] != '\n' && p[i] != '\r'; i++) {
97 if (!strncmp(p + i, "-->", 3)) {
105 identifier_len = strcspn(p, "\r\n");
114 if ((ts_start = read_ts(p)) == AV_NOPTS_VALUE)
116 if (!(p = strstr(p, "-->")))
119 do p++; while (*p == ' ' || *p == '\t');
120 if ((ts_end = read_ts(p)) == AV_NOPTS_VALUE)
123 /* optional cue settings */
124 p += strcspn(p, "\n\t ");
125 while (*p == '\t' || *p == ' ')
128 settings_len = strcspn(p, "\r\n");
136 sub = ff_subtitles_queue_insert(&webvtt->q, p, strlen(p), 0);
138 res = AVERROR(ENOMEM);
143 sub->duration = ts_end - ts_start;
145 #define SET_SIDE_DATA(name, type) do { \
147 uint8_t *buf = av_packet_new_side_data(sub, type, name##_len); \
149 res = AVERROR(ENOMEM); \
152 memcpy(buf, name, name##_len); \
156 SET_SIDE_DATA(identifier, AV_PKT_DATA_WEBVTT_IDENTIFIER);
157 SET_SIDE_DATA(settings, AV_PKT_DATA_WEBVTT_SETTINGS);
160 ff_subtitles_queue_finalize(&webvtt->q);
163 av_bprint_finalize(&cue, NULL);
164 av_bprint_finalize(&header, NULL);
168 static int webvtt_read_packet(AVFormatContext *s, AVPacket *pkt)
170 WebVTTContext *webvtt = s->priv_data;
171 return ff_subtitles_queue_read_packet(&webvtt->q, pkt);
174 static int webvtt_read_seek(AVFormatContext *s, int stream_index,
175 int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
177 WebVTTContext *webvtt = s->priv_data;
178 return ff_subtitles_queue_seek(&webvtt->q, s, stream_index,
179 min_ts, ts, max_ts, flags);
182 static int webvtt_read_close(AVFormatContext *s)
184 WebVTTContext *webvtt = s->priv_data;
185 ff_subtitles_queue_clean(&webvtt->q);
189 AVInputFormat ff_webvtt_demuxer = {
191 .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
192 .priv_data_size = sizeof(WebVTTContext),
193 .read_probe = webvtt_probe,
194 .read_header = webvtt_read_header,
195 .read_packet = webvtt_read_packet,
196 .read_seek2 = webvtt_read_seek,
197 .read_close = webvtt_read_close,