1/*
2 * Copyright (C) 2008  Ramiro Polla
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#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
39static int msnwc_tcp_probe(const 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
74static int msnwc_tcp_read_header(AVFormatContext *ctx)
75{
76    AVIOContext *pb = ctx->pb;
77    AVCodecParameters *par;
78    AVStream *st;
79
80    st = avformat_new_stream(ctx, NULL);
81    if (!st)
82        return AVERROR(ENOMEM);
83
84    par             = st->codecpar;
85    par->codec_type = AVMEDIA_TYPE_VIDEO;
86    par->codec_id   = AV_CODEC_ID_MIMIC;
87    par->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 && !avio_feof(pb)) ;
94
95    if(avio_feof(pb)) {
96        av_log(ctx, AV_LOG_ERROR, "Could not find valid start.\n");
97        return AVERROR_INVALIDDATA;
98    }
99
100    return 0;
101}
102
103static 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
139const 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};
146