Document the av_base64_encode/decode functions.
[libav.git] / libavformat / ncdec.c
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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
66 uint32_t state=-1;
67 while (state != NC_VIDEO_FLAG) {
68 if (url_feof(s->pb))
69 return AVERROR(EIO);
70 state = (state<<8) + get_byte(s->pb);
71 }
72
73 get_byte(s->pb);
74 size = get_le16(s->pb);
75 url_fskip(s->pb, 9);
76
77 if (size == 0) {
78 av_log(s, AV_LOG_DEBUG, "Next packet size is zero\n");
79 return AVERROR(EAGAIN);
80 }
81
82 int ret = av_get_packet(s->pb, pkt, size);
83 if (ret != size) {
84 if (ret > 0) av_free_packet(pkt);
85 return AVERROR(EIO);
86 }
87
88 pkt->stream_index = 0;
89 return size;
90}
91
92AVInputFormat nc_demuxer = {
93 "nc",
94 NULL_IF_CONFIG_SMALL("NC camera feed format"),
95 0,
96 nc_probe,
97 nc_read_header,
98 nc_read_packet,
99 .extensions = "v",
100};