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/*
* SubRip subtitle muxer
* Copyright (c) 2012 Nicolas George <nicolas.george@normalesup.org>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "internal.h"
#include "libavutil/log.h"
/* TODO: add options for:
- character encoding;
- LF / CRLF;
- byte order mark.
*/
typedef struct SRTContext{
unsigned index;
} SRTContext;
static int srt_write_header(AVFormatContext *avf)
{
if (avf->nb_streams != 1 ||
avf->streams[0]->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) {
av_log(avf, AV_LOG_ERROR,
"SRT supports only a single subtitles stream.\n");
return AVERROR(EINVAL);
}
if (avf->streams[0]->codec->codec_id != AV_CODEC_ID_TEXT &&
avf->streams[0]->codec->codec_id != AV_CODEC_ID_SUBRIP &&
avf->streams[0]->codec->codec_id != AV_CODEC_ID_SRT) {
av_log(avf, AV_LOG_ERROR,
"Unsupported subtitles codec: %s\n",
avcodec_get_name(avf->streams[0]->codec->codec_id));
return AVERROR(EINVAL);
}
avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);
return 0;
}
static int srt_write_packet(AVFormatContext *avf, AVPacket *pkt)
{
SRTContext *srt = avf->priv_data;
int write_ts = avf->streams[0]->codec->codec_id != AV_CODEC_ID_SRT;
srt->index++;
if (write_ts) {
char buf[64];
int64_t s = pkt->pts, e, d = pkt->duration;
int len;
if (d <= 0)
/* For backward compatibility, fallback to convergence_duration. */
d = pkt->convergence_duration;
if (s == AV_NOPTS_VALUE || d <= 0) {
av_log(avf, AV_LOG_ERROR, "Insufficient timestamps.\n");
return AVERROR(EINVAL);
}
e = s + d;
len = snprintf(buf, sizeof(buf),
"%d\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d\n",
srt->index,
(int)(s / 3600000), (int)(s / 60000) % 60,
(int)(s / 1000) % 60, (int)(s % 1000),
(int)(e / 3600000), (int)(e / 60000) % 60,
(int)(e / 1000) % 60, (int)(e % 1000));
avio_write(avf->pb, buf, len);
}
avio_write(avf->pb, pkt->data, pkt->size);
if (write_ts)
avio_write(avf->pb, "\n\n", 2);
avio_flush(avf->pb);
return 0;
}
AVOutputFormat ff_srt_muxer = {
.name = "srt",
.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
.mime_type = "application/x-subrip",
.extensions = "srt",
.priv_data_size = sizeof(SRTContext),
.write_header = srt_write_header,
.write_packet = srt_write_packet,
.flags = AVFMT_VARIABLE_FPS,
.subtitle_codec = AV_CODEC_ID_TEXT,
};
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