msnwc_tcp: Use the correct return values
[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 &&
53 height == 240) && !(width == 160 && height == 120))
54 continue;
55 bytestream += 2; // keyframe
56 bytestream += 4; // size
57 fourcc = bytestream_get_le32(&bytestream);
58 if (fourcc != MKTAG('M', 'L', '2', '0'))
59 continue;
60
61 if (i) {
62 if (i < 14) /* starts with SwitchBoard connection info */
63 return AVPROBE_SCORE_MAX / 2;
64 else /* starts in the middle of stream */
65 return AVPROBE_SCORE_MAX / 3;
66 } else {
67 return AVPROBE_SCORE_MAX;
68 }
69 }
70
71 return 0;
72 }
73
74 static int msnwc_tcp_read_header(AVFormatContext *ctx)
75 {
76 AVIOContext *pb = ctx->pb;
77 AVCodecContext *codec;
78 AVStream *st;
79
80 st = avformat_new_stream(ctx, NULL);
81 if (!st)
82 return AVERROR(ENOMEM);
83
84 codec = st->codec;
85 codec->codec_type = AVMEDIA_TYPE_VIDEO;
86 codec->codec_id = AV_CODEC_ID_MIMIC;
87 codec->codec_tag = MKTAG('M', 'L', '2', '0');
88
89 avpriv_set_pts_info(st, 32, 1, 1000);
90
91 /* Some files start with "connected\r\n\r\n".
92 * So skip until we find the first byte of struct size */
93 while (avio_r8(pb) != HEADER_SIZE && !pb->eof_reached) ;
94
95 if (pb->eof_reached) {
96 av_log(ctx, AV_LOG_ERROR, "Could not find valid start.");
97 return AVERROR_INVALIDDATA;
98 }
99
100 return 0;
101 }
102
103 static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
104 {
105 AVIOContext *pb = ctx->pb;
106 uint16_t keyframe;
107 uint32_t size, timestamp;
108 int ret;
109
110 avio_skip(pb, 1); /* one byte has been read ahead */
111 avio_skip(pb, 2);
112 avio_skip(pb, 2);
113 keyframe = avio_rl16(pb);
114 size = avio_rl32(pb);
115 avio_skip(pb, 4);
116 avio_skip(pb, 4);
117 timestamp = avio_rl32(pb);
118
119 if (!size)
120 return AVERROR_INVALIDDATA;
121
122 if ((ret = av_get_packet(pb, pkt, size)) < 0)
123 return ret;
124
125 avio_skip(pb, 1); /* Read ahead one byte of struct size like read_header */
126
127 pkt->pts = timestamp;
128 pkt->dts = timestamp;
129 pkt->stream_index = 0;
130
131 /* Some aMsn generated videos (or was it Mercury Messenger?) don't set
132 * this bit and rely on the codec to get keyframe information */
133 if (keyframe & 1)
134 pkt->flags |= AV_PKT_FLAG_KEY;
135
136 return HEADER_SIZE + size;
137 }
138
139 AVInputFormat ff_msnwc_tcp_demuxer = {
140 .name = "msnwctcp",
141 .long_name = NULL_IF_CONFIG_SMALL("MSN TCP Webcam stream"),
142 .read_probe = msnwc_tcp_probe,
143 .read_header = msnwc_tcp_read_header,
144 .read_packet = msnwc_tcp_read_packet,
145 };