FFmpeg4/libavformat/iv8.c

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2023-07-02 12:20:28 +00:00
/*
* Copyright (c) 2009 Michael Niedermayer
*
* 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"
static int probe(const AVProbeData *p)
{
// the single file I have starts with that, I do not know if others do, too
if( p->buf[0] == 1
&& p->buf[1] == 1
&& p->buf[2] == 3
&& p->buf[3] == 0xB8
&& p->buf[4] == 0x80
&& p->buf[5] == 0x60
)
return AVPROBE_SCORE_MAX-2;
return 0;
}
static int read_header(AVFormatContext *s)
{
AVStream *st;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_MPEG4;
st->need_parsing = AVSTREAM_PARSE_FULL;
avpriv_set_pts_info(st, 64, 1, 90000);
return 0;
}
static int read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret, size, pts, type, flags;
int first_pkt = 0;
int frame_complete = 0;
while (!frame_complete) {
type = avio_rb16(s->pb); // 257 or 258
size = avio_rb16(s->pb);
flags = avio_rb16(s->pb); //some flags, 0x80 indicates end of frame
avio_rb16(s->pb); //packet number
pts = avio_rb32(s->pb);
avio_rb32(s->pb); //6A 13 E3 88
frame_complete = flags & 0x80;
size -= 12;
if (size < 1)
return -1;
if (type == 258) {
avio_skip(s->pb, size);
frame_complete = 0;
continue;
}
if (!first_pkt) {
ret = av_get_packet(s->pb, pkt, size);
if (ret < 0)
return ret;
first_pkt = 1;
pkt->pts = pts;
pkt->pos -= 16;
} else {
ret = av_append_packet(s->pb, pkt, size);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "failed to grow packet\n");
return ret;
}
}
if (ret < size) {
av_log(s, AV_LOG_ERROR, "Truncated packet! Read %d of %d bytes\n",
ret, size);
pkt->flags |= AV_PKT_FLAG_CORRUPT;
break;
}
}
pkt->stream_index = 0;
return 0;
}
AVInputFormat ff_iv8_demuxer = {
.name = "iv8",
.long_name = NULL_IF_CONFIG_SMALL("IndigoVision 8000 video"),
.read_probe = probe,
.read_header = read_header,
.read_packet = read_packet,
.flags = AVFMT_GENERIC_INDEX,
};