ffmpeg/libavformat/ncdec.c
Andreas Rheinhardt b800327f4c avformat/avformat: Add FFInputFormat, hide internals of AVInputFormat
This commit does for AVInputFormat what commit
59c9dc82f450638a3068deeb1db5c56f6d155752 did for AVOutputFormat:
It adds a new type FFInputFormat, moves all the internals
of AVInputFormat to it and adds a now reduced AVInputFormat
as first member.

This does not affect/improve extensibility of both public
or private fields for demuxers (it is still a mess due to lavd).

This is possible since 50f34172e0cca2cabc5836308ec66dbf93f5f2a3
(which removed the last usage of an internal field of AVInputFormat
in fftools).

(Hint: tools/probetest.c accesses the internals of FFInputFormat
as well, but given that it is a testing tool this is not considered
a problem.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-03-07 08:53:31 -03:00

102 lines
2.6 KiB
C

/*
* NC camera feed demuxer
* Copyright (c) 2009 Nicolas Martin (martinic at iro dot umontreal dot ca)
* Edouard Auvinet
*
* 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 "libavutil/intreadwrite.h"
#include "avformat.h"
#include "demux.h"
#include "internal.h"
#define NC_VIDEO_FLAG 0x1A5
static int nc_probe(const AVProbeData *probe_packet)
{
int size;
if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG)
return 0;
size = AV_RL16(probe_packet->buf + 5);
if (size + 20 > probe_packet->buf_size)
return AVPROBE_SCORE_MAX/4;
if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG)
return AVPROBE_SCORE_MAX;
return 0;
}
static int nc_read_header(AVFormatContext *s)
{
AVStream *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;
ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL;
avpriv_set_pts_info(st, 64, 1, 100);
return 0;
}
static int nc_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int size;
int ret;
uint32_t state=-1;
while (state != NC_VIDEO_FLAG) {
if (avio_feof(s->pb))
return AVERROR(EIO);
state = (state<<8) + avio_r8(s->pb);
}
avio_r8(s->pb);
size = avio_rl16(s->pb);
avio_skip(s->pb, 9);
if (size == 0) {
av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n");
return AVERROR(EAGAIN);
}
ret = av_get_packet(s->pb, pkt, size);
if (ret != size) {
return AVERROR(EIO);
}
pkt->stream_index = 0;
return size;
}
const FFInputFormat ff_nc_demuxer = {
.p.name = "nc",
.p.long_name = NULL_IF_CONFIG_SMALL("NC camera feed"),
.p.extensions = "v",
.read_probe = nc_probe,
.read_header = nc_read_header,
.read_packet = nc_read_packet,
};