ffmpeg/libavformat/sccenc.c

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/*
* SCC muxer
* Copyright (c) 2017 Paul B Mahol
*
* 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"
#include "libavutil/intreadwrite.h"
typedef struct SCCContext {
int prev_h, prev_m, prev_s, prev_f;
int inside;
int n;
} SCCContext;
static int scc_write_header(AVFormatContext *avf)
{
SCCContext *scc = avf->priv_data;
if (avf->nb_streams != 1 ||
avf->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
av_log(avf, AV_LOG_ERROR,
"SCC supports only a single subtitles stream.\n");
return AVERROR(EINVAL);
}
if (avf->streams[0]->codecpar->codec_id != AV_CODEC_ID_EIA_608) {
av_log(avf, AV_LOG_ERROR,
"Unsupported subtitles codec: %s\n",
avcodec_get_name(avf->streams[0]->codecpar->codec_id));
return AVERROR(EINVAL);
}
avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);
avio_printf(avf->pb, "Scenarist_SCC V1.0\n");
scc->prev_h = scc->prev_m = scc->prev_s = scc->prev_f = -1;
scc->inside = 0;
return 0;
}
static int scc_write_packet(AVFormatContext *avf, AVPacket *pkt)
{
SCCContext *scc = avf->priv_data;
int64_t pts = pkt->pts;
int i, h, m, s, f;
if (pts == AV_NOPTS_VALUE) {
av_log(avf, AV_LOG_WARNING,
"Insufficient timestamps.\n");
return 0;
}
h = (int)(pts / (3600000));
m = (int)(pts / (60000)) % 60;
s = (int)(pts / 1000) % 60;
f = (int)(pts % 1000) / 33;
for (i = 0; i < pkt->size; i+=3) {
if (pkt->data[i] == 0xfc && ((pkt->data[i + 1] != 0x80 || pkt->data[i + 2] != 0x80)))
break;
}
if (i >= pkt->size)
return 0;
if (!scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
scc->inside = 1;
}
for (i = 0; i < pkt->size; i+=3) {
if (i + 3 > pkt->size)
break;
if (pkt->data[i] != 0xfc || (pkt->data[i + 1] == 0x80 && pkt->data[i + 2] == 0x80))
continue;
if (!scc->inside) {
avio_printf(avf->pb, "\n%02d:%02d:%02d:%02d\t", h, m, s, f);
scc->inside = 1;
}
if (scc->n > 0)
avio_printf(avf->pb, " ");
avio_printf(avf->pb, "%02x%02x", pkt->data[i + 1], pkt->data[i + 2]);
scc->n++;
}
if (scc->inside && (scc->prev_h != h || scc->prev_m != m || scc->prev_s != s || scc->prev_f != f)) {
avio_printf(avf->pb, "\n");
scc->n = 0;
scc->inside = 0;
}
scc->prev_h = h;
scc->prev_m = m;
scc->prev_s = s;
scc->prev_f = f;
return 0;
}
const AVOutputFormat ff_scc_muxer = {
.name = "scc",
.long_name = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
.extensions = "scc",
.priv_data_size = sizeof(SCCContext),
.write_header = scc_write_header,
.write_packet = scc_write_packet,
.flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
.subtitle_codec = AV_CODEC_ID_EIA_608,
};