ffmpeg/libavformat/stldec.c

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/*
* Copyright (c) 2014 Eejya Singh
*
* 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
* STL subtitles format demuxer
* @see https://documentation.apple.com/en/dvdstudiopro/usermanual/index.html#chapter=19%26section=13%26tasks=true
*/
#include "avformat.h"
#include "internal.h"
#include "subtitles.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/avstring.h"
typedef struct {
FFDemuxSubtitlesQueue q;
} STLContext;
static int stl_probe(AVProbeData *p)
{
char c;
const unsigned char *ptr = p->buf;
if (AV_RB24(ptr) == 0xEFBBBF)
ptr += 3; /* skip UTF-8 BOM */
while (*ptr == '\r' || *ptr == '\n' || *ptr == '$' || !strncmp(ptr, "//" , 2))
ptr += ff_subtitles_next_line(ptr);
if (sscanf(ptr, "%*d:%*d:%*d:%*d , %*d:%*d:%*d:%*d , %c", &c) == 1)
return AVPROBE_SCORE_MAX;
return 0;
}
static int64_t get_pts(char **buf, int *duration)
{
int hh1, mm1, ss1, ms1;
int hh2, mm2, ss2, ms2;
int len = 0;
if (sscanf(*buf, "%2d:%2d:%2d:%2d , %2d:%2d:%2d:%2d , %n",
&hh1, &mm1, &ss1, &ms1,
&hh2, &mm2, &ss2, &ms2, &len) >= 8 && len > 0) {
int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
*duration = end - start;
*buf += len;
return start;
}
return AV_NOPTS_VALUE;
}
static int stl_read_header(AVFormatContext *s)
{
STLContext *stl = s->priv_data;
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
avpriv_set_pts_info(st, 64, 1, 100);
st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codec->codec_id = AV_CODEC_ID_STL;
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;
int duration;
if (!len)
break;
line[strcspn(line, "\r\n")] = 0;
pts_start = get_pts(&p , &duration);
if (pts_start != AV_NOPTS_VALUE) {
AVPacket *sub;
sub = ff_subtitles_queue_insert(&stl->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, &stl->q);
return 0;
}
static int stl_read_packet(AVFormatContext *s, AVPacket *pkt)
{
STLContext *stl = s->priv_data;
return ff_subtitles_queue_read_packet(&stl->q, pkt);
}
static int stl_read_seek(AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
STLContext *stl = s->priv_data;
return ff_subtitles_queue_seek(&stl->q, s, stream_index,
min_ts, ts, max_ts, flags);
}
static int stl_read_close(AVFormatContext *s)
{
STLContext *stl = s->priv_data;
ff_subtitles_queue_clean(&stl->q);
return 0;
}
AVInputFormat ff_stl_demuxer = {
.name = "stl",
.long_name = NULL_IF_CONFIG_SMALL("Spruce subtitle format"),
.priv_data_size = sizeof(STLContext),
.read_probe = stl_probe,
.read_header = stl_read_header,
.read_packet = stl_read_packet,
.read_seek2 = stl_read_seek,
.read_close = stl_read_close,
.extensions = "stl",
};