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/*
* MicroDVD subtitle demuxer
* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.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/intreadwrite.h"
#define MAX_LINESIZE 2048
typedef struct {
uint8_t lines[3][MAX_LINESIZE];
int64_t pos[3];
AVPacket last_pkt;
int last_pkt_ready;
} 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 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, frame;
double fps;
char c;
if (!st)
return -1;
for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
microdvd->pos[i] = avio_tell(s->pb);
ff_get_line(s->pb, microdvd->lines[i], sizeof(microdvd->lines[i]));
if ((sscanf(microdvd->lines[i], "{%d}{}%6lf", &frame, &fps) == 2 ||
sscanf(microdvd->lines[i], "{%d}{%*d}%6lf", &frame, &fps) == 2)
&& frame <= 1 && fps > 3 && fps < 100)
pts_info = av_d2q(fps, 100000);
if (sscanf(microdvd->lines[i], "{DEFAULT}{}%c", &c) == 1) {
st->codec->extradata = av_strdup(microdvd->lines[i] + 11);
st->codec->extradata_size = strlen(st->codec->extradata);
i--;
}
}
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 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;
}
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;
}
static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
{
MicroDVDContext *microdvd = s->priv_data;
char buffer[MAX_LINESIZE];
int64_t pos = avio_tell(s->pb);
int i, len = 0, res = AVERROR_EOF;
// last packet has its duration set but couldn't be raised earlier
if (microdvd->last_pkt_ready) {
*pkt = microdvd->last_pkt;
microdvd->last_pkt_ready = 0;
return 0;
}
for (i=0; i<FF_ARRAY_ELEMS(microdvd->lines); i++) {
if (microdvd->lines[i][0]) {
strcpy(buffer, microdvd->lines[i]);
pos = microdvd->pos[i];
len = strlen(buffer);
microdvd->lines[i][0] = 0;
break;
}
}
if (!len)
len = ff_get_line(s->pb, buffer, sizeof(buffer));
if (microdvd->last_pkt.duration == -1 && !buffer[0]) {
// if the previous subtitle line had no duration, last until the end of
// the presentation
microdvd->last_pkt.duration = 0;
*pkt = microdvd->last_pkt;
pkt->duration = -1;
res = 0;
} else if (buffer[0] && !(res = av_new_packet(pkt, len))) {
memcpy(pkt->data, buffer, len);
pkt->flags |= AV_PKT_FLAG_KEY;
pkt->pos = pos;
pkt->pts = pkt->dts = get_pts(buffer);
if (pkt->pts != AV_NOPTS_VALUE) {
pkt->duration = get_duration(buffer);
if (microdvd->last_pkt.duration == -1) {
// previous packet wasn't raised because it was lacking the
// duration info, so set its duration with the new packet pts
// and raise it
AVPacket tmp_pkt;
tmp_pkt = microdvd->last_pkt;
tmp_pkt.duration = pkt->pts - tmp_pkt.pts;
microdvd->last_pkt = *pkt;
microdvd->last_pkt_ready = pkt->duration != -1;
*pkt = tmp_pkt;
} else if (pkt->duration == -1) {
// no packet without duration queued, and current one is
// lacking the duration info, we need to parse another subtitle
// event.
microdvd->last_pkt = *pkt;
res = AVERROR(EAGAIN);
}
}
}
return res;
}
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,
.flags = AVFMT_GENERIC_INDEX,
};
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