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libavformat
ncdec.c
Go to the documentation of this file.
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/*
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* NC camera feed demuxer
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* Copyright (c) 2009 Nicolas Martin (martinic at iro dot umontreal dot ca)
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* Edouard Auvinet
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "
libavutil/intreadwrite.h
"
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#include "
avformat.h
"
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#include "
internal.h
"
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#define NC_VIDEO_FLAG 0x1A5
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static
int
nc_probe
(
AVProbeData
*probe_packet)
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{
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int
size
;
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if
(
AV_RB32
(probe_packet->
buf
) !=
NC_VIDEO_FLAG
)
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return
0;
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size =
AV_RL16
(probe_packet->
buf
+ 5);
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if
(size + 20 > probe_packet->
buf_size
)
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return
AVPROBE_SCORE_MAX
/4;
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if
(
AV_RB32
(probe_packet->
buf
+16+size) ==
NC_VIDEO_FLAG
)
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return
AVPROBE_SCORE_MAX
;
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return
0;
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}
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static
int
nc_read_header
(
AVFormatContext
*
s
)
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{
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AVStream
*st =
avformat_new_stream
(s, NULL);
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if
(!st)
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return
AVERROR
(ENOMEM);
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st->
codec
->
codec_type
=
AVMEDIA_TYPE_VIDEO
;
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st->
codec
->
codec_id
=
AV_CODEC_ID_MPEG4
;
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st->
need_parsing
=
AVSTREAM_PARSE_FULL
;
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avpriv_set_pts_info
(st, 64, 1, 100);
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return
0;
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}
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static
int
nc_read_packet
(
AVFormatContext
*
s
,
AVPacket
*
pkt
)
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{
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int
size
;
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int
ret
;
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uint32_t
state
=-1;
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while
(state !=
NC_VIDEO_FLAG
) {
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if
(
url_feof
(s->
pb
))
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return
AVERROR
(EIO);
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state = (state<<8) +
avio_r8
(s->
pb
);
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}
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avio_r8
(s->
pb
);
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size =
avio_rl16
(s->
pb
);
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avio_skip
(s->
pb
, 9);
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if
(size == 0) {
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av_log
(s,
AV_LOG_DEBUG
,
"Next packet size is zero\n"
);
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return
AVERROR
(EAGAIN);
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}
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ret =
av_get_packet
(s->
pb
, pkt, size);
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if
(ret != size) {
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if
(ret > 0)
av_free_packet
(pkt);
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return
AVERROR
(EIO);
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}
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pkt->
stream_index
= 0;
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return
size
;
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}
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AVInputFormat
ff_nc_demuxer
= {
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.
name
=
"nc"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"NC camera feed"
),
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.read_probe =
nc_probe
,
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.read_header =
nc_read_header
,
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.read_packet =
nc_read_packet
,
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.extensions =
"v"
,
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};
Generated on Wed Jul 10 2013 23:48:13 for FFmpeg by
1.8.2