b6d30feb9d6d1c97f8bd6dc5d9693d716598314f
[libav.git] / libavformat / msnwc_tcp.c
1 /*
2 * Copyright (C) 2008 Ramiro Polla
3 *
4 * This file is part of Libav.
5 *
6 * Libav is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * Libav is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "libavcodec/bytestream.h"
22 #include "avformat.h"
23 #include "internal.h"
24
25 #define HEADER_SIZE 24
26
27 /*
28 * Header structure:
29 * uint16_t ss; // struct size
30 * uint16_t width; // frame width
31 * uint16_t height; // frame height
32 * uint16_t ff; // keyframe + some other info(???)
33 * uint32_t size; // size of data
34 * uint32_t fourcc; // ML20
35 * uint32_t u3; // ?
36 * uint32_t ts; // time
37 */
38
39 static int msnwc_tcp_probe(AVProbeData *p)
40 {
41 int i;
42
43 for(i = 0 ; i + HEADER_SIZE <= p->buf_size ; i++) {
44 uint16_t width, height;
45 uint32_t fourcc;
46 const uint8_t *bytestream = p->buf+i;
47
48 if(bytestream_get_le16(&bytestream) != HEADER_SIZE)
49 continue;
50 width = bytestream_get_le16(&bytestream);
51 height = bytestream_get_le16(&bytestream);
52 if(!(width==320 && height==240) && !(width==160 && height==120))
53 continue;
54 bytestream += 2; // keyframe
55 bytestream += 4; // size
56 fourcc = bytestream_get_le32(&bytestream);
57 if(fourcc != MKTAG('M', 'L', '2', '0'))
58 continue;
59
60 if(i) {
61 if(i < 14) /* starts with SwitchBoard connection info */
62 return AVPROBE_SCORE_MAX / 2;
63 else /* starts in the middle of stream */
64 return AVPROBE_SCORE_MAX / 3;
65 } else {
66 return AVPROBE_SCORE_MAX;
67 }
68 }
69
70 return -1;
71 }
72
73 static int msnwc_tcp_read_header(AVFormatContext *ctx)
74 {
75 AVIOContext *pb = ctx->pb;
76 AVCodecContext *codec;
77 AVStream *st;
78
79 st = avformat_new_stream(ctx, NULL);
80 if(!st)
81 return AVERROR(ENOMEM);
82
83 codec = st->codec;
84 codec->codec_type = AVMEDIA_TYPE_VIDEO;
85 codec->codec_id = AV_CODEC_ID_MIMIC;
86 codec->codec_tag = MKTAG('M', 'L', '2', '0');
87
88 avpriv_set_pts_info(st, 32, 1, 1000);
89
90 /* Some files start with "connected\r\n\r\n".
91 * So skip until we find the first byte of struct size */
92 while(avio_r8(pb) != HEADER_SIZE && !pb->eof_reached);
93
94 if(pb->eof_reached) {
95 av_log(ctx, AV_LOG_ERROR, "Could not find valid start.");
96 return -1;
97 }
98
99 return 0;
100 }
101
102 static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
103 {
104 AVIOContext *pb = ctx->pb;
105 uint16_t keyframe;
106 uint32_t size, timestamp;
107
108 avio_skip(pb, 1); /* one byte has been read ahead */
109 avio_skip(pb, 2);
110 avio_skip(pb, 2);
111 keyframe = avio_rl16(pb);
112 size = avio_rl32(pb);
113 avio_skip(pb, 4);
114 avio_skip(pb, 4);
115 timestamp = avio_rl32(pb);
116
117 if(!size || av_get_packet(pb, pkt, size) != size)
118 return -1;
119
120 avio_skip(pb, 1); /* Read ahead one byte of struct size like read_header */
121
122 pkt->pts = timestamp;
123 pkt->dts = timestamp;
124 pkt->stream_index = 0;
125
126 /* Some aMsn generated videos (or was it Mercury Messenger?) don't set
127 * this bit and rely on the codec to get keyframe information */
128 if(keyframe&1)
129 pkt->flags |= AV_PKT_FLAG_KEY;
130
131 return HEADER_SIZE + size;
132 }
133
134 AVInputFormat ff_msnwc_tcp_demuxer = {
135 .name = "msnwctcp",
136 .long_name = NULL_IF_CONFIG_SMALL("MSN TCP Webcam stream"),
137 .read_probe = msnwc_tcp_probe,
138 .read_header = msnwc_tcp_read_header,
139 .read_packet = msnwc_tcp_read_packet,
140 };