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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 && 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 0;
71 }
72 
74 {
75  AVIOContext *pb = ctx->pb;
76  AVCodecContext *codec;
77  AVStream *st;
78 
79  st = avformat_new_stream(ctx, NULL);
80  if(!st)
81  return AVERROR(ENOMEM);
82 
83  codec = st->codec;
85  codec->codec_id = AV_CODEC_ID_MIMIC;
86  codec->codec_tag = MKTAG('M', 'L', '2', '0');
87 
88  avpriv_set_pts_info(st, 32, 1, 1000);
89 
90  /* Some files start with "connected\r\n\r\n".
91  * So skip until we find the first byte of struct size */
92  while(avio_r8(pb) != HEADER_SIZE && !avio_feof(pb));
93 
94  if(avio_feof(pb)) {
95  av_log(ctx, AV_LOG_ERROR, "Could not find valid start.\n");
96  return -1;
97  }
98 
99  return 0;
100 }
101 
103 {
104  AVIOContext *pb = ctx->pb;
105  uint16_t keyframe;
106  uint32_t size, timestamp;
107 
108  avio_skip(pb, 1); /* one byte has been read ahead */
109  avio_skip(pb, 2);
110  avio_skip(pb, 2);
111  keyframe = avio_rl16(pb);
112  size = avio_rl32(pb);
113  avio_skip(pb, 4);
114  avio_skip(pb, 4);
115  timestamp = avio_rl32(pb);
116 
117  if(!size || av_get_packet(pb, pkt, size) != size)
118  return -1;
119 
120  avio_skip(pb, 1); /* Read ahead one byte of struct size like read_header */
121 
122  pkt->pts = timestamp;
123  pkt->dts = timestamp;
124  pkt->stream_index = 0;
125 
126  /* Some aMsn generated videos (or was it Mercury Messenger?) don't set
127  * this bit and rely on the codec to get keyframe information */
128  if(keyframe&1)
129  pkt->flags |= AV_PKT_FLAG_KEY;
130 
131  return HEADER_SIZE + size;
132 }
133 
135  .name = "msnwctcp",
136  .long_name = NULL_IF_CONFIG_SMALL("MSN TCP Webcam stream"),
137  .read_probe = msnwc_tcp_probe,
138  .read_header = msnwc_tcp_read_header,
139  .read_packet = msnwc_tcp_read_packet,
140 };
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:111
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:4075
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:277
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1273
AVInputFormat ff_msnwc_tcp_demuxer
Definition: msnwc_tcp.c:134
uint8_t
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:3741
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:244
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:1468
#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:659
#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:175
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1428
static int msnwc_tcp_read_header(AVFormatContext *ctx)
Definition: msnwc_tcp.c:73
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:529
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:861
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:451
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
static int msnwc_tcp_read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: msnwc_tcp.c:102
Stream structure.
Definition: avformat.h:842
enum AVMediaType codec_type
Definition: avcodec.h:1509
static int msnwc_tcp_probe(AVProbeData *p)
Definition: msnwc_tcp.c:39
enum AVCodecID codec_id
Definition: avcodec.h:1518
AVIOContext * pb
I/O context.
Definition: avformat.h:1315
main external API structure.
Definition: avcodec.h:1501
unsigned int codec_tag
fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
Definition: avcodec.h:1533
BYTE int const BYTE int int int height
Definition: avisynth_c.h:676
#define HEADER_SIZE
Definition: msnwc_tcp.c:25
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:460
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:643
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:1421
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:628
int avio_feof(AVIOContext *s)
feof() equivalent for AVIOContext.
Definition: aviobuf.c:301
int stream_index
Definition: avcodec.h:1424
#define MKTAG(a, b, c, d)
Definition: common.h:315
This structure stores compressed data.
Definition: avcodec.h:1399
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1415
static int width