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
26#define NC_VIDEO_FLAG 0x1A5
27
28static int nc_probe(AVProbeData *probe_packet)
29{
30    int size;
31
32    if (AV_RB32(probe_packet->buf) != NC_VIDEO_FLAG)
33        return 0;
34
35    size = AV_RL16(probe_packet->buf + 5);
36
37    if (size + 20 > probe_packet->buf_size)
38        return 3*AVPROBE_SCORE_MAX/2;
39
40    if (AV_RB32(probe_packet->buf+16+size) == NC_VIDEO_FLAG)
41        return AVPROBE_SCORE_MAX;
42
43    return 0;
44}
45
46static int nc_read_header(AVFormatContext *s, AVFormatParameters *ap)
47{
48    AVStream *st = av_new_stream(s, 0);
49
50    if (!st)
51        return AVERROR(ENOMEM);
52
53    st->codec->codec_type = CODEC_TYPE_VIDEO;
54    st->codec->codec_id   = CODEC_ID_MPEG4;
55    st->need_parsing      = AVSTREAM_PARSE_FULL;
56
57    av_set_pts_info(st, 64, 1, 100);
58
59    return 0;
60}
61
62static int nc_read_packet(AVFormatContext *s, AVPacket *pkt)
63{
64    int size;
65    int ret;
66
67    uint32_t state=-1;
68    while (state != NC_VIDEO_FLAG) {
69        if (url_feof(s->pb))
70            return AVERROR(EIO);
71        state = (state<<8) + get_byte(s->pb);
72    }
73
74    get_byte(s->pb);
75    size = get_le16(s->pb);
76    url_fskip(s->pb, 9);
77
78    if (size == 0) {
79        av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n");
80        return AVERROR(EAGAIN);
81    }
82
83    ret = av_get_packet(s->pb, pkt, size);
84    if (ret != size) {
85        if (ret > 0) av_free_packet(pkt);
86        return AVERROR(EIO);
87    }
88
89    pkt->stream_index = 0;
90    return size;
91}
92
93AVInputFormat nc_demuxer = {
94    "nc",
95    NULL_IF_CONFIG_SMALL("NC camera feed format"),
96    0,
97    nc_probe,
98    nc_read_header,
99    nc_read_packet,
100    .extensions = "v",
101};
102