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
30static 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
46static 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
64static int webvtt_write_packet(AVFormatContext *ctx, AVPacket *pkt)
65{
66    AVIOContext  *pb = ctx->pb;
67    size_t id_size, settings_size;
68    int id_size_int, settings_size_int;
69    uint8_t *id, *settings;
70
71    avio_printf(pb, "\n");
72
73    id = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_IDENTIFIER,
74                                 &id_size);
75
76    if (id_size > INT_MAX)
77        return AVERROR(EINVAL);
78
79    id_size_int = id_size;
80    if (id && id_size_int > 0)
81        avio_printf(pb, "%.*s\n", id_size_int, id);
82
83    webvtt_write_time(pb, pkt->pts);
84    avio_printf(pb, " --> ");
85    webvtt_write_time(pb, pkt->pts + pkt->duration);
86
87    settings = av_packet_get_side_data(pkt, AV_PKT_DATA_WEBVTT_SETTINGS,
88                                       &settings_size);
89
90    if (settings_size > INT_MAX)
91        return AVERROR(EINVAL);
92
93    settings_size_int = settings_size;
94    if (settings && settings_size_int > 0)
95        avio_printf(pb, " %.*s", settings_size_int, settings);
96
97    avio_printf(pb, "\n");
98
99    avio_write(pb, pkt->data, pkt->size);
100    avio_printf(pb, "\n");
101
102    return 0;
103}
104
105const AVOutputFormat ff_webvtt_muxer = {
106    .name              = "webvtt",
107    .long_name         = NULL_IF_CONFIG_SMALL("WebVTT subtitle"),
108    .extensions        = "vtt",
109    .mime_type         = "text/vtt",
110    .flags             = AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
111    .subtitle_codec    = AV_CODEC_ID_WEBVTT,
112    .write_header      = webvtt_write_header,
113    .write_packet      = webvtt_write_packet,
114};
115