1 /*
2 * NC camera feed demuxer
3 * Copyright (c) 2009 Nicolas Martin (martinic at iro dot umontreal dot ca)
4 * Edouard Auvinet
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "libavutil/intreadwrite.h"
24 #include "avformat.h"
25 #include "internal.h"
26
27 #define NC_VIDEO_FLAG 0x1A5
28
nc_probe(const AVProbeData * probe_packet)29 static int nc_probe(const AVProbeData *probe_packet)
30 {
31 int size;
32
33 if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG)
34 return 0;
35
36 size = AV_RL16(probe_packet->buf + 5);
37
38 if (size + 20 > probe_packet->buf_size)
39 return AVPROBE_SCORE_MAX/4;
40
41 if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG)
42 return AVPROBE_SCORE_MAX;
43
44 return 0;
45 }
46
nc_read_header(AVFormatContext * s)47 static int nc_read_header(AVFormatContext *s)
48 {
49 AVStream *st = avformat_new_stream(s, NULL);
50
51 if (!st)
52 return AVERROR(ENOMEM);
53
54 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
55 st->codecpar->codec_id = AV_CODEC_ID_MPEG4;
56 st->need_parsing = AVSTREAM_PARSE_FULL;
57
58 avpriv_set_pts_info(st, 64, 1, 100);
59
60 return 0;
61 }
62
nc_read_packet(AVFormatContext * s,AVPacket * pkt)63 static int nc_read_packet(AVFormatContext *s, AVPacket *pkt)
64 {
65 int size;
66 int ret;
67
68 uint32_t state=-1;
69 while (state != NC_VIDEO_FLAG) {
70 if (avio_feof(s->pb))
71 return AVERROR(EIO);
72 state = (state<<8) + avio_r8(s->pb);
73 }
74
75 avio_r8(s->pb);
76 size = avio_rl16(s->pb);
77 avio_skip(s->pb, 9);
78
79 if (size == 0) {
80 av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n");
81 return AVERROR(EAGAIN);
82 }
83
84 ret = av_get_packet(s->pb, pkt, size);
85 if (ret != size) {
86 return AVERROR(EIO);
87 }
88
89 pkt->stream_index = 0;
90 return size;
91 }
92
93 AVInputFormat ff_nc_demuxer = {
94 .name = "nc",
95 .long_name = NULL_IF_CONFIG_SMALL("NC camera feed"),
96 .read_probe = nc_probe,
97 .read_header = nc_read_header,
98 .read_packet = nc_read_packet,
99 .extensions = "v",
100 };
101