1/*
2 * Copyright (C) 2008  Ramiro Polla <ramiro@lisha.ufsc.br>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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
24#define HEADER_SIZE         24
25
26/*
27 * Header structure:
28 *  uint16_t    ss;     // struct size
29 *  uint16_t    width;  // frame width
30 *  uint16_t    height; // frame height
31 *  uint16_t    ff;     // keyframe + some other info(???)
32 *  uint32_t    size;   // size of data
33 *  uint32_t    fourcc; // ML20
34 *  uint32_t    u3;     // ?
35 *  uint32_t    ts;     // time
36 */
37
38static int msnwc_tcp_probe(AVProbeData *p)
39{
40    int i;
41
42    for(i = 0 ; i + HEADER_SIZE <= p->buf_size ; i++) {
43        uint16_t width, height;
44        uint32_t fourcc;
45        const uint8_t *bytestream = p->buf+i;
46
47        if(bytestream_get_le16(&bytestream) != HEADER_SIZE)
48            continue;
49        width  = bytestream_get_le16(&bytestream);
50        height = bytestream_get_le16(&bytestream);
51        if(!(width==320 && height==240) && !(width==160 && height==120))
52            continue;
53        bytestream += 2; // keyframe
54        bytestream += 4; // size
55        fourcc = bytestream_get_le32(&bytestream);
56        if(fourcc != MKTAG('M', 'L', '2', '0'))
57            continue;
58
59        if(i) {
60            if(i < 14)  /* starts with SwitchBoard connection info */
61                return AVPROBE_SCORE_MAX / 2;
62            else        /* starts in the middle of stream */
63                return AVPROBE_SCORE_MAX / 3;
64        } else {
65            return AVPROBE_SCORE_MAX;
66        }
67    }
68
69    return -1;
70}
71
72static int msnwc_tcp_read_header(AVFormatContext *ctx, AVFormatParameters *ap)
73{
74    ByteIOContext *pb = ctx->pb;
75    AVCodecContext *codec;
76    AVStream *st;
77
78    st = av_new_stream(ctx, 0);
79    if(!st)
80        return AVERROR(ENOMEM);
81
82    codec = st->codec;
83    codec->codec_type = AVMEDIA_TYPE_VIDEO;
84    codec->codec_id = CODEC_ID_MIMIC;
85    codec->codec_tag = MKTAG('M', 'L', '2', '0');
86
87    av_set_pts_info(st, 32, 1, 1000);
88
89    /* Some files start with "connected\r\n\r\n".
90     * So skip until we find the first byte of struct size */
91    while(get_byte(pb) != HEADER_SIZE && !url_feof(pb));
92
93    if(url_feof(pb)) {
94        av_log(ctx, AV_LOG_ERROR, "Could not find valid start.");
95        return -1;
96    }
97
98    return 0;
99}
100
101static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
102{
103    ByteIOContext *pb = ctx->pb;
104    uint16_t keyframe;
105    uint32_t size, timestamp;
106
107    url_fskip(pb, 1); /* one byte has been read ahead */
108    url_fskip(pb, 2);
109    url_fskip(pb, 2);
110    keyframe = get_le16(pb);
111    size = get_le32(pb);
112    url_fskip(pb, 4);
113    url_fskip(pb, 4);
114    timestamp = get_le32(pb);
115
116    if(!size || av_get_packet(pb, pkt, size) != size)
117        return -1;
118
119    url_fskip(pb, 1); /* Read ahead one byte of struct size like read_header */
120
121    pkt->pts = timestamp;
122    pkt->dts = timestamp;
123    pkt->stream_index = 0;
124
125    /* Some aMsn generated videos (or was it Mercury Messenger?) don't set
126     * this bit and rely on the codec to get keyframe information */
127    if(keyframe&1)
128        pkt->flags |= AV_PKT_FLAG_KEY;
129
130    return HEADER_SIZE + size;
131}
132
133AVInputFormat msnwc_tcp_demuxer = {
134    "msnwctcp",
135    NULL_IF_CONFIG_SMALL("MSN TCP Webcam stream"),
136    0,
137    msnwc_tcp_probe,
138    msnwc_tcp_read_header,
139    msnwc_tcp_read_packet,
140};
141