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 int64_t extract_cue(AVBPrint *buf, AVIOContext *pb)
59 int prev_chr_is_eol = 0;
60 int64_t pos = avio_tell(pb);
67 if (c == '\r' || c == '\n') {
70 prev_chr_is_eol = (c == '\n');
74 av_bprint_chars(buf, c, 1);
76 av_bprint_chars(buf, '\0', 1);
80 static int webvtt_read_header(AVFormatContext *s)
82 WebVTTContext *webvtt = s->priv_data;
85 AVStream *st = avformat_new_stream(s, NULL);
88 return AVERROR(ENOMEM);
89 avpriv_set_pts_info(st, 64, 1, 1000);
90 st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
91 st->codec->codec_id = AV_CODEC_ID_WEBVTT;
93 av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
94 av_bprint_init(&cue, 0, AV_BPRINT_SIZE_UNLIMITED);
98 int64_t pos = extract_cue(&cue, s->pb);
100 const char *p = cue.str;
101 const char *identifier = p;
102 //const char *settings = NULL;
103 int64_t ts_start, ts_end;
108 /* ignore header chunk */
109 if (!strncmp(p, "\xEF\xBB\xBFWEBVTT", 9) ||
110 !strncmp(p, "WEBVTT", 6))
113 /* optional cue identifier (can be a number like in SRT or some kind of
114 * chaptering id), silently skip it */
115 for (i = 0; p[i] && p[i] != '\n'; i++) {
116 if (!strncmp(p + i, "-->", 3)) {
122 p += strcspn(p, "\n");
125 if ((ts_start = read_ts(p)) == AV_NOPTS_VALUE)
127 if (!(p = strstr(p, "-->")))
130 do p++; while (*p == ' ' || *p == '\t');
131 if ((ts_end = read_ts(p)) == AV_NOPTS_VALUE)
134 /* optional cue settings, TODO: store in side_data */
135 p += strcspn(p, "\n\t ");
136 while (*p == '\t' || *p == ' ')
140 p += strcspn(p, "\n");
146 len = cue.str + cue.len - p - 1;
147 sub = ff_subtitles_queue_insert(&webvtt->q, p, len, 0);
149 res = AVERROR(ENOMEM);
154 sub->duration = ts_end - ts_start;
157 ff_subtitles_queue_finalize(&webvtt->q);
160 av_bprint_finalize(&cue, NULL);
161 av_bprint_finalize(&header, NULL);
165 static int webvtt_read_packet(AVFormatContext *s, AVPacket *pkt)
167 WebVTTContext *webvtt = s->priv_data;
168 return ff_subtitles_queue_read_packet(&webvtt->q, pkt);
171 static int webvtt_read_seek(AVFormatContext *s, int stream_index,
172 int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
174 WebVTTContext *webvtt = s->priv_data;
175 return ff_subtitles_queue_seek(&webvtt->q, s, stream_index,
176 min_ts, ts, max_ts, flags);
179 static int webvtt_read_close(AVFormatContext *s)
181 WebVTTContext *webvtt = s->priv_data;
182 ff_subtitles_queue_clean(&webvtt->q);
186 AVInputFormat ff_webvtt_demuxer = {
188 .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
189 .priv_data_size = sizeof(WebVTTContext),
190 .read_probe = webvtt_probe,
191 .read_header = webvtt_read_header,
192 .read_packet = webvtt_read_packet,
193 .read_seek2 = webvtt_read_seek,
194 .read_close = webvtt_read_close,
195 .flags = AVFMT_GENERIC_INDEX,