blob: 8cadcc7cd7508f2e984063b21dd687ab349e45b6
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 | |
29 | static int nc_probe(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 | |
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 | |
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 | if (ret > 0) av_packet_unref(pkt); |
87 | return AVERROR(EIO); |
88 | } |
89 | |
90 | pkt->stream_index = 0; |
91 | return size; |
92 | } |
93 | |
94 | AVInputFormat ff_nc_demuxer = { |
95 | .name = "nc", |
96 | .long_name = NULL_IF_CONFIG_SMALL("NC camera feed"), |
97 | .read_probe = nc_probe, |
98 | .read_header = nc_read_header, |
99 | .read_packet = nc_read_packet, |
100 | .extensions = "v", |
101 | }; |
102 |