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libavformat
astdec.c
Go to the documentation of this file.
1
/*
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* AST demuxer
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* Copyright (c) 2012 Paul B Mahol
4
*
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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
9
* 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/channel_layout.h
"
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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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#include "
ast.h
"
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static
int
ast_probe
(
AVProbeData
*p)
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{
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if
(
AV_RL32
(p->
buf
) ==
MKTAG
(
'S'
,
'T'
,
'R'
,
'M'
) &&
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AV_RB16
(p->
buf
+ 10) &&
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AV_RB16
(p->
buf
+ 12) &&
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AV_RB32
(p->
buf
+ 16))
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return
AVPROBE_SCORE_MAX
/ 3 * 2;
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return
0;
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}
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static
int
ast_read_header
(
AVFormatContext
*s)
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{
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int
depth
;
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AVStream
*st;
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st =
avformat_new_stream
(s,
NULL
);
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if
(!st)
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return
AVERROR
(ENOMEM);
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avio_skip
(s->
pb
, 8);
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st->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
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st->
codec
->
codec_id
=
ff_codec_get_id
(
ff_codec_ast_tags
,
avio_rb16
(s->
pb
));
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depth =
avio_rb16
(s->
pb
);
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if
(depth != 16) {
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av_log_ask_for_sample
(s,
"unsupported depth %d\n"
, depth);
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return
AVERROR_INVALIDDATA
;
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}
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st->
codec
->
channels
=
avio_rb16
(s->
pb
);
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if
(!st->
codec
->
channels
)
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return
AVERROR_INVALIDDATA
;
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if
(st->
codec
->
channels
== 2)
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st->
codec
->
channel_layout
=
AV_CH_LAYOUT_STEREO
;
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else
if
(st->
codec
->
channels
== 4)
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st->
codec
->
channel_layout
=
AV_CH_LAYOUT_4POINT0
;
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avio_skip
(s->
pb
, 2);
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st->
codec
->
sample_rate
=
avio_rb32
(s->
pb
);
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if
(st->
codec
->
sample_rate
<= 0)
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return
AVERROR_INVALIDDATA
;
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st->
start_time
= 0;
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st->
duration
=
avio_rb32
(s->
pb
);
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avio_skip
(s->
pb
, 40);
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avpriv_set_pts_info
(st, 64, 1, st->
codec
->
sample_rate
);
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return
0;
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}
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static
int
ast_read_packet
(
AVFormatContext
*s,
AVPacket
*
pkt
)
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{
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uint32_t type,
size
;
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int64_t pos;
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int
ret;
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if
(
url_feof
(s->
pb
))
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return
AVERROR_EOF
;
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pos =
avio_tell
(s->
pb
);
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type =
avio_rl32
(s->
pb
);
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size =
avio_rb32
(s->
pb
);
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if
(size > INT_MAX / s->
streams
[0]->
codec
->
channels
)
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return
AVERROR_INVALIDDATA
;
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size *= s->
streams
[0]->
codec
->
channels
;
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if
((ret =
avio_skip
(s->
pb
, 24)) < 0)
// padding
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return
ret;
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if
(type ==
MKTAG
(
'B'
,
'L'
,
'C'
,
'K'
)) {
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ret =
av_get_packet
(s->
pb
, pkt, size);
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pkt->
stream_index
= 0;
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pkt->
pos
= pos;
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}
else
{
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av_log
(s,
AV_LOG_ERROR
,
"unknown chunk %x\n"
, type);
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avio_skip
(s->
pb
, size);
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ret =
AVERROR_INVALIDDATA
;
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}
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return
ret;
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}
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AVInputFormat
ff_ast_demuxer
= {
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.
name
=
"ast"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"AST (Audio Stream)"
),
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.read_probe =
ast_probe
,
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.read_header =
ast_read_header
,
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.read_packet =
ast_read_packet
,
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.extensions =
"ast"
,
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.flags =
AVFMT_GENERIC_INDEX
,
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.codec_tag = (
const
AVCodecTag
*
const
[]){
ff_codec_ast_tags
, 0},
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};
Generated on Sat May 25 2013 04:01:16 for FFmpeg by
1.8.2