msnwc_tcp: Correctly report failure
[libav.git] / libavformat / msnwc_tcp.c
CommitLineData
0f3444e1 1/*
cbf5d22d 2 * Copyright (C) 2008 Ramiro Polla
0f3444e1 3 *
2912e87a 4 * This file is part of Libav.
0f3444e1 5 *
2912e87a 6 * Libav is free software; you can redistribute it and/or
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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 *
2912e87a 11 * Libav is distributed in the hope that it will be useful,
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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
2912e87a 17 * License along with Libav; if not, write to the Free Software
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18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
245976da 21#include "libavcodec/bytestream.h"
0f3444e1 22#include "avformat.h"
c3f9ebf7 23#include "internal.h"
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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
39static 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
6e9651d1 73static int msnwc_tcp_read_header(AVFormatContext *ctx)
0f3444e1 74{
ae628ec1 75 AVIOContext *pb = ctx->pb;
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76 AVCodecContext *codec;
77 AVStream *st;
78
3b3bbdd3 79 st = avformat_new_stream(ctx, NULL);
0f3444e1 80 if(!st)
2874c81c 81 return AVERROR(ENOMEM);
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82
83 codec = st->codec;
72415b2a 84 codec->codec_type = AVMEDIA_TYPE_VIDEO;
36ef5369 85 codec->codec_id = AV_CODEC_ID_MIMIC;
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86 codec->codec_tag = MKTAG('M', 'L', '2', '0');
87
c3f9ebf7 88 avpriv_set_pts_info(st, 32, 1, 1000);
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89
90 /* Some files start with "connected\r\n\r\n".
91 * So skip until we find the first byte of struct size */
66e5b1df 92 while(avio_r8(pb) != HEADER_SIZE && !pb->eof_reached);
0f3444e1 93
66e5b1df 94 if(pb->eof_reached) {
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95 av_log(ctx, AV_LOG_ERROR, "Could not find valid start.");
96 return -1;
97 }
98
99 return 0;
100}
101
102static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
103{
ae628ec1 104 AVIOContext *pb = ctx->pb;
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105 uint16_t keyframe;
106 uint32_t size, timestamp;
4dfbc7a7 107 int ret;
0f3444e1 108
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109 avio_skip(pb, 1); /* one byte has been read ahead */
110 avio_skip(pb, 2);
111 avio_skip(pb, 2);
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112 keyframe = avio_rl16(pb);
113 size = avio_rl32(pb);
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114 avio_skip(pb, 4);
115 avio_skip(pb, 4);
b7effd4e 116 timestamp = avio_rl32(pb);
0f3444e1 117
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118 if (!size)
119 return AVERROR_INVALIDDATA;
120
121 if ((ret = av_get_packet(pb, pkt, size)) < 0)
122 return ret;
0f3444e1 123
45a8a02a 124 avio_skip(pb, 1); /* Read ahead one byte of struct size like read_header */
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125
126 pkt->pts = timestamp;
127 pkt->dts = timestamp;
128 pkt->stream_index = 0;
129
130 /* Some aMsn generated videos (or was it Mercury Messenger?) don't set
131 * this bit and rely on the codec to get keyframe information */
132 if(keyframe&1)
cc947f04 133 pkt->flags |= AV_PKT_FLAG_KEY;
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134
135 return HEADER_SIZE + size;
136}
137
c6610a21 138AVInputFormat ff_msnwc_tcp_demuxer = {
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139 .name = "msnwctcp",
140 .long_name = NULL_IF_CONFIG_SMALL("MSN TCP Webcam stream"),
141 .read_probe = msnwc_tcp_probe,
142 .read_header = msnwc_tcp_read_header,
143 .read_packet = msnwc_tcp_read_packet,
0f3444e1 144};