path: root/libavformat/srtenc.c (plain)
blob: d811a4da0e45d1c389a1d058737d201ec6aeaceb

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
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
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	int size, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
65	const uint8_t *p;
66
67	p = av_packet_get_side_data(pkt, AV_PKT_DATA_SUBTITLE_POSITION, &size);
68	if (p && size == 16) {
69	x1 = AV_RL32(p );
70	y1 = AV_RL32(p + 4);
71	x2 = AV_RL32(p + 8);
72	y2 = AV_RL32(p + 12);
73	}
74
75	#if FF_API_CONVERGENCE_DURATION
76	FF_DISABLE_DEPRECATION_WARNINGS
77	if (d <= 0)
78	/* For backward compatibility, fallback to convergence_duration. */
79	d = pkt->convergence_duration;
80	FF_ENABLE_DEPRECATION_WARNINGS
81	#endif
82	if (s == AV_NOPTS_VALUE || d < 0) {
83	av_log(avf, AV_LOG_WARNING,
84	"Insufficient timestamps in event number %d.\n", srt->index);
85	return 0;
86	}
87	e = s + d;
88	avio_printf(avf->pb, "%d\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d",
89	srt->index,
90	(int)(s / 3600000), (int)(s / 60000) % 60,
91	(int)(s / 1000) % 60, (int)(s % 1000),
92	(int)(e / 3600000), (int)(e / 60000) % 60,
93	(int)(e / 1000) % 60, (int)(e % 1000));
94	if (p)
95	avio_printf(avf->pb, " X1:%03d X2:%03d Y1:%03d Y2:%03d",
96	x1, x2, y1, y2);
97	avio_printf(avf->pb, "\n");
98
99	avio_write(avf->pb, pkt->data, pkt->size);
100	avio_write(avf->pb, "\n\n", 2);
101	srt->index++;
102	return 0;
103	}
104
105	AVOutputFormat ff_srt_muxer = {
106	.name = "srt",
107	.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
108	.mime_type = "application/x-subrip",
109	.extensions = "srt",
110	.priv_data_size = sizeof(SRTContext),
111	.write_header = srt_write_header,
112	.write_packet = srt_write_packet,
113	.flags = AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
114	.subtitle_codec = AV_CODEC_ID_SUBRIP,
115	};
116