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FFmpeg/libavformat/mpl2dec.c
Andreas Rheinhardt ea5bdc8893 avformat/subtitles: Deduplicate subtitles' read_(packet|seek|close)
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2021-07-18 04:26:35 +02:00

137 lines
3.7 KiB
C

/*
* Copyright (c) 2012 Clément Bœsch
*
* 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
*/
/**
* @file
* MPL2 subtitles format demuxer
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#include "subtitles.h"
typedef struct {
FFDemuxSubtitlesQueue q;
} MPL2Context;
static int mpl2_probe(const AVProbeData *p)
{
int i;
char c;
int64_t start, end;
const unsigned char *ptr = p->buf;
const unsigned char *ptr_end = ptr + p->buf_size;
if (AV_RB24(ptr) == 0xefbbbf)
ptr += 3;
for (i = 0; i < 2; i++) {
if (sscanf(ptr, "[%"SCNd64"][%"SCNd64"]%c", &start, &end, &c) != 3 &&
sscanf(ptr, "[%"SCNd64"][]%c", &start, &c) != 2)
return 0;
ptr += ff_subtitles_next_line(ptr);
if (ptr >= ptr_end)
return 0;
}
return AVPROBE_SCORE_MAX;
}
static int read_ts(char **line, int64_t *pts_start, int64_t *duration)
{
char c;
int len;
int64_t end;
if (sscanf(*line, "[%"SCNd64"][]%c%n",
pts_start, &c, &len) >= 2) {
*duration = -1;
*line += len - 1;
return 0;
}
if (sscanf(*line, "[%"SCNd64"][%"SCNd64"]%c%n",
pts_start, &end, &c, &len) >= 3) {
if (end < *pts_start || end - (uint64_t)*pts_start > INT64_MAX) {
*duration = -1;
} else
*duration = end - *pts_start;
*line += len - 1;
return 0;
}
return -1;
}
static int mpl2_read_header(AVFormatContext *s)
{
MPL2Context *mpl2 = s->priv_data;
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 64, 1, 10);
st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codecpar->codec_id = AV_CODEC_ID_MPL2;
if (avio_rb24(s->pb) != 0xefbbbf)
avio_seek(s->pb, -3, SEEK_CUR);
while (!avio_feof(s->pb)) {
char line[4096];
char *p = line;
const int64_t pos = avio_tell(s->pb);
int len = ff_get_line(s->pb, line, sizeof(line));
int64_t pts_start;
int64_t duration;
if (!len)
break;
line[strcspn(line, "\r\n")] = 0;
if (!read_ts(&p, &pts_start, &duration)) {
AVPacket *sub;
sub = ff_subtitles_queue_insert(&mpl2->q, p, strlen(p), 0);
if (!sub)
return AVERROR(ENOMEM);
sub->pos = pos;
sub->pts = pts_start;
sub->duration = duration;
}
}
ff_subtitles_queue_finalize(s, &mpl2->q);
return 0;
}
const AVInputFormat ff_mpl2_demuxer = {
.name = "mpl2",
.long_name = NULL_IF_CONFIG_SMALL("MPL2 subtitles"),
.priv_data_size = sizeof(MPL2Context),
.flags_internal = FF_FMT_INIT_CLEANUP,
.read_probe = mpl2_probe,
.read_header = mpl2_read_header,
.extensions = "txt,mpl2",
.read_packet = ff_subtitles_read_packet,
.read_seek2 = ff_subtitles_read_seek,
.read_close = ff_subtitles_read_close,
};