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eaf5d011 NM |
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 | ||
28 | static 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 | ||
46 | static 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 | ||
62 | static 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 | ||
92 | AVInputFormat 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 | }; |