1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
/*
* 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"
#define NC_VIDEO_FLAG 0x1A5
static int nc_probe(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, AVFormatParameters *ap)
{
AVStream *st = av_new_stream(s, 0);
if (!st)
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_MPEG4;
st->need_parsing = AVSTREAM_PARSE_FULL;
av_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 (s->pb->eof_reached)
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) {
if (ret > 0) av_free_packet(pkt);
return AVERROR(EIO);
}
pkt->stream_index = 0;
return size;
}
AVInputFormat ff_nc_demuxer = {
"nc",
NULL_IF_CONFIG_SMALL("NC camera feed format"),
0,
nc_probe,
nc_read_header,
nc_read_packet,
.extensions = "v",
};
|
