1 /*
2 * Copyright (c) 2013 Matthew Heaney
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 muxer
24 * @see http://dev.w3.org/html5/webvtt/
25 */
26
27 #include "avformat.h"
28 #include "internal.h"
29
webvtt_write_time(AVIOContext * pb,int64_t millisec)30 static void webvtt_write_time(AVIOContext *pb, int64_t millisec)
31 {
32 int64_t sec, min, hour;
33 sec = millisec / 1000;
34 millisec -= 1000 * sec;
35 min = sec / 60;
36 sec -= 60 * min;
37 hour = min / 60;
38 min -= 60 * hour;
39
40 if (hour > 0)
41 avio_printf(pb, "%02"PRId64":", hour);
42
43 avio_printf(pb, "%02"PRId64":%02"PRId64".%03"PRId64"", min, sec, millisec);
44 }
45
webvtt_write_header(AVFormatContext * ctx)46 static int webvtt_write_header(AVFormatContext *ctx)
47 {
48 AVStream *s = ctx->streams[0];
49 AVCodecParameters *par = ctx->streams[0]->codecpar;
50 AVIOContext *pb = ctx->pb;
51
52 if (ctx->nb_streams != 1 || par->codec_id != AV_CODEC_ID_WEBVTT) {
53 av_log(ctx, AV_LOG_ERROR, "Exactly one WebVTT stream is needed.\n");
54 return AVERROR(EINVAL);
55 }
56
57 avpriv_set_pts_info(s, 64, 1, 1000);
58
59 avio_printf(pb, "WEBVTT\n");
60
61 return 0;
62 }
63
webvtt_write_packet(AVFormatContext * ctx,AVPacket * pkt)64 static int webvtt_write_packet(AVFormatContext *ctx, AVPacket *pkt)
65 {
66 AVIOContext *pb = ctx->pb;
67 buffer_size_t id_size, settings_size;
68 uint8_t *id, *settings;
69
70 avio_printf(pb, "\n");
71
72 id = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_IDENTIFIER,
73 &id_size);
74
75 if (id && id_size > 0)
76 avio_printf(pb, "%.*s\n", id_size, id);
77
78 webvtt_write_time(pb, pkt->pts);
79 avio_printf(pb, " --> ");
80 webvtt_write_time(pb, pkt->pts + pkt->duration);
81
82 settings = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_SETTINGS,
83 &settings_size);
84
85 if (settings && settings_size > 0)
86 avio_printf(pb, " %.*s", settings_size, settings);
87
88 avio_printf(pb, "\n");
89
90 avio_write(pb, pkt->data, pkt->size);
91 avio_printf(pb, "\n");
92
93 return 0;
94 }
95
96 AVOutputFormat ff_webvtt_muxer = {
97 .name = "webvtt",
98 .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
99 .extensions = "vtt",
100 .mime_type = "text/vtt",
101 .flags = AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
102 .subtitle_codec = AV_CODEC_ID_WEBVTT,
103 .write_header = webvtt_write_header,
104 .write_packet = webvtt_write_packet,
105 };
106