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msnwc_tcp.c
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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 
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 
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;
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 
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 
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 };
#define NULL
Definition: coverity.c:32
uint32_t fourcc
Definition: hwcontext_qsv.c:90
Bytestream IO Context.
Definition: avio.h:147
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4581
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3981
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:304
static AVPacket pkt
This struct describes the properties of an encoded stream.
Definition: avcodec.h:3973
Format I/O context.
Definition: avformat.h:1338
AVInputFormat ff_msnwc_tcp_demuxer
Definition: msnwc_tcp.c:139
uint8_t
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4214
#define height
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:289
ptrdiff_t size
Definition: opengl_enc.c:101
#define av_log(a,...)
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1633
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:726
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3977
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1607
static int msnwc_tcp_read_header(AVFormatContext *ctx)
Definition: msnwc_tcp.c:74
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:595
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:464
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:463
#define width
AVFormatContext * ctx
Definition: movenc.c:48
static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: msnwc_tcp.c:103
Stream structure.
Definition: avformat.h:889
static int msnwc_tcp_probe(AVProbeData *p)
Definition: msnwc_tcp.c:39
AVIOContext * pb
I/O context.
Definition: avformat.h:1380
#define HEADER_SIZE
Definition: msnwc_tcp.c:25
This structure contains the data a format has to probe a file.
Definition: avformat.h:461
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:473
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:710
Main libavformat public API header.
int64_t dts
Decompression timestamp in AVStream->time_base units; the time at which the packet is decompressed...
Definition: avcodec.h:1600
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:664
AVCodecParameters * codecpar
Definition: avformat.h:1241
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:328
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: avcodec.h:3985
int stream_index
Definition: avcodec.h:1603
#define MKTAG(a, b, c, d)
Definition: common.h:342
This structure stores compressed data.
Definition: avcodec.h:1578
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1594