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libavformat
avr.c
Go to the documentation of this file.
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/*
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* AVR demuxer
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* Copyright (c) 2012 Paul B Mahol
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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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#include "
pcm.h
"
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static
int
avr_probe
(
AVProbeData
*p)
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{
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if
(
AV_RL32
(p->
buf
) !=
MKTAG
(
'2'
,
'B'
,
'I'
,
'T'
))
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return
0;
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if
(!
AV_RB16
(p->
buf
+12) ||
AV_RB16
(p->
buf
+12) > 256)
// channels
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return
AVPROBE_SCORE_EXTENSION
/2;
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if
(
AV_RB16
(p->
buf
+14) > 256)
// bps
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return
AVPROBE_SCORE_EXTENSION
/2;
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return
AVPROBE_SCORE_EXTENSION
;
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}
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static
int
avr_read_header
(
AVFormatContext
*
s
)
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{
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uint16_t chan, sign,
bps
;
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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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st->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
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avio_skip
(s->
pb
, 4);
// magic
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avio_skip
(s->
pb
, 8);
// sample_name
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chan =
avio_rb16
(s->
pb
);
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if
(!chan) {
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st->
codec
->
channels
= 1;
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}
else
if
(chan == 0xFFFFu) {
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st->
codec
->
channels
= 2;
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}
else
{
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avpriv_request_sample
(s,
"chan %d"
, chan);
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return
AVERROR_PATCHWELCOME
;
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}
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st->
codec
->
bits_per_coded_sample
= bps =
avio_rb16
(s->
pb
);
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sign =
avio_rb16
(s->
pb
);
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avio_skip
(s->
pb
, 2);
// loop
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avio_skip
(s->
pb
, 2);
// midi
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avio_skip
(s->
pb
, 1);
// replay speed
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st->
codec
->
sample_rate
=
avio_rb24
(s->
pb
);
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avio_skip
(s->
pb
, 4 * 3);
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avio_skip
(s->
pb
, 2 * 3);
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avio_skip
(s->
pb
, 20);
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avio_skip
(s->
pb
, 64);
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st->
codec
->
codec_id
=
ff_get_pcm_codec_id
(bps, 0, 1, sign);
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if
(st->
codec
->
codec_id
==
AV_CODEC_ID_NONE
) {
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avpriv_request_sample
(s,
"Bps %d and sign %d"
, bps, sign);
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return
AVERROR_PATCHWELCOME
;
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}
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st->
codec
->
block_align
= bps * st->
codec
->
channels
/ 8;
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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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AVInputFormat
ff_avr_demuxer
= {
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.
name
=
"avr"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"AVR (Audio Visual Research)"
),
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.read_probe =
avr_probe
,
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.read_header =
avr_read_header
,
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.read_packet =
ff_pcm_read_packet
,
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.read_seek =
ff_pcm_read_seek
,
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.extensions =
"avr"
,
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.flags =
AVFMT_GENERIC_INDEX
,
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};
Generated on Fri Dec 5 2014 04:42:10 for FFmpeg by
1.8.2