1 /*
2 * SubRip subtitle muxer
3 * Copyright (c) 2012 Nicolas George <nicolas.george@normalesup.org>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "avformat.h"
23 #include "internal.h"
24 #include "libavutil/log.h"
25 #include "libavutil/intreadwrite.h"
26
27 /* TODO: add options for:
28 - character encoding;
29 - LF / CRLF;
30 - byte order mark.
31 */
32
33 typedef struct SRTContext{
34 unsigned index;
35 } SRTContext;
36
srt_write_header(AVFormatContext * avf)37 static int srt_write_header(AVFormatContext *avf)
38 {
39 SRTContext *srt = avf->priv_data;
40
41 if (avf->nb_streams != 1 ||
42 avf->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
43 av_log(avf, AV_LOG_ERROR,
44 "SRT supports only a single subtitles stream.\n");
45 return AVERROR(EINVAL);
46 }
47 if (avf->streams[0]->codecpar->codec_id != AV_CODEC_ID_TEXT &&
48 avf->streams[0]->codecpar->codec_id != AV_CODEC_ID_SUBRIP) {
49 av_log(avf, AV_LOG_ERROR,
50 "Unsupported subtitles codec: %s\n",
51 avcodec_get_name(avf->streams[0]->codecpar->codec_id));
52 return AVERROR(EINVAL);
53 }
54 avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);
55 srt->index = 1;
56 return 0;
57 }
58
srt_write_packet(AVFormatContext * avf,AVPacket * pkt)59 static int srt_write_packet(AVFormatContext *avf, AVPacket *pkt)
60 {
61 SRTContext *srt = avf->priv_data;
62
63 int64_t s = pkt->pts, e, d = pkt->duration;
64 buffer_size_t size;
65 int x1 = -1, y1 = -1, x2 = -1, y2 = -1;
66 const uint8_t *p;
67
68 p = av_packet_get_side_data(pkt, AV_PKT_DATA_SUBTITLE_POSITION, &size);
69 if (p && size == 16) {
70 x1 = AV_RL32(p );
71 y1 = AV_RL32(p + 4);
72 x2 = AV_RL32(p + 8);
73 y2 = AV_RL32(p + 12);
74 }
75
76 #if FF_API_CONVERGENCE_DURATION
77 FF_DISABLE_DEPRECATION_WARNINGS
78 if (d <= 0)
79 /* For backward compatibility, fallback to convergence_duration. */
80 d = pkt->convergence_duration;
81 FF_ENABLE_DEPRECATION_WARNINGS
82 #endif
83 if (s == AV_NOPTS_VALUE || d < 0) {
84 av_log(avf, AV_LOG_WARNING,
85 "Insufficient timestamps in event number %d.\n", srt->index);
86 return 0;
87 }
88 e = s + d;
89 avio_printf(avf->pb, "%d\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d",
90 srt->index,
91 (int)(s / 3600000), (int)(s / 60000) % 60,
92 (int)(s / 1000) % 60, (int)(s % 1000),
93 (int)(e / 3600000), (int)(e / 60000) % 60,
94 (int)(e / 1000) % 60, (int)(e % 1000));
95 if (p)
96 avio_printf(avf->pb, " X1:%03d X2:%03d Y1:%03d Y2:%03d",
97 x1, x2, y1, y2);
98 avio_printf(avf->pb, "\n");
99
100 avio_write(avf->pb, pkt->data, pkt->size);
101 avio_write(avf->pb, "\n\n", 2);
102 srt->index++;
103 return 0;
104 }
105
106 AVOutputFormat ff_srt_muxer = {
107 .name = "srt",
108 .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
109 .mime_type = "application/x-subrip",
110 .extensions = "srt",
111 .priv_data_size = sizeof(SRTContext),
112 .write_header = srt_write_header,
113 .write_packet = srt_write_packet,
114 .flags = AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
115 .subtitle_codec = AV_CODEC_ID_SUBRIP,
116 };
117