ffmpeg/libavformat/microdvddec.c

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/*
* MicroDVD subtitle demuxer
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
* Copyright (c) 2012 Clément Bœsch <ubitux@gmail.com>
*
* 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 "subtitles.h"
#include "libavutil/intreadwrite.h"
#define MAX_LINESIZE 2048
typedef struct {
FFDemuxSubtitlesQueue q;
} MicroDVDContext;
static int microdvd_probe(AVProbeData *p)
{
unsigned char c, *ptr = p->buf;
int i;
if (AV_RB24(ptr) == 0xEFBBBF)
ptr += 3; /* skip UTF-8 BOM */
for (i=0; i<3; i++) {
if (sscanf(ptr, "{%*d}{}%c", &c) != 1 &&
sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
return 0;
ptr += strcspn(ptr, "\n") + 1;
}
return AVPROBE_SCORE_MAX;
}
static int64_t get_pts(const char *buf)
{
int frame;
char c;
if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
return frame;
return AV_NOPTS_VALUE;
}
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static int get_duration(const char *buf)
{
int frame_start, frame_end;
if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
return frame_end - frame_start;
return -1;
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}
static int microdvd_read_header(AVFormatContext *s)
{
AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */
MicroDVDContext *microdvd = s->priv_data;
AVStream *st = avformat_new_stream(s, NULL);
int i = 0;
char line[MAX_LINESIZE];
if (!st)
return AVERROR(ENOMEM);
while (!url_feof(s->pb)) {
AVPacket *sub;
int64_t pos = avio_tell(s->pb);
int len = ff_get_line(s->pb, line, sizeof(line));
if (!len)
break;
if (i < 3) {
int frame;
double fps;
char c;
i++;
if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 ||
sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
&& frame <= 1 && fps > 3 && fps < 100)
pts_info = av_d2q(fps, 100000);
if (!st->codec->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
st->codec->extradata = av_strdup(line + 11);
if (!st->codec->extradata)
return AVERROR(ENOMEM);
st->codec->extradata_size = strlen(st->codec->extradata) + 1;
continue;
}
}
sub = ff_subtitles_queue_insert(&microdvd->q, line, len, 0);
if (!sub)
return AVERROR(ENOMEM);
sub->pos = pos;
sub->pts = get_pts(sub->data);
sub->duration = get_duration(sub->data);
}
ff_subtitles_queue_finalize(&microdvd->q);
avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
st->codec->codec_id = CODEC_ID_MICRODVD;
return 0;
}
static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
{
MicroDVDContext *microdvd = s->priv_data;
return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
}
static int microdvd_read_close(AVFormatContext *s)
{
MicroDVDContext *microdvd = s->priv_data;
ff_subtitles_queue_clean(&microdvd->q);
return 0;
}
AVInputFormat ff_microdvd_demuxer = {
.name = "microdvd",
.long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
.priv_data_size = sizeof(MicroDVDContext),
.read_probe = microdvd_probe,
.read_header = microdvd_read_header,
.read_packet = microdvd_read_packet,
.read_close = microdvd_read_close,
.flags = AVFMT_GENERIC_INDEX,
};