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libavformat
aacdec.c
Go to the documentation of this file.
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/*
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* raw ADTS AAC demuxer
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* Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
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* Copyright (c) 2009 Robert Swain ( rob opendot cl )
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*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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 "
rawdec.h
"
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#include "
id3v1.h
"
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static
int
adts_aac_probe
(
AVProbeData
*p)
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{
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int
max_frames = 0, first_frames = 0;
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int
fsize, frames;
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uint8_t
*buf0 = p->
buf
;
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uint8_t
*buf2;
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uint8_t
*buf;
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uint8_t
*end = buf0 + p->
buf_size
- 7;
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buf = buf0;
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for
(; buf < end; buf= buf2+1) {
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buf2 = buf;
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for
(frames = 0; buf2 < end; frames++) {
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uint32_t header =
AV_RB16
(buf2);
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if
((header&0xFFF6) != 0xFFF0)
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break
;
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fsize = (
AV_RB32
(buf2 + 3) >> 13) & 0x1FFF;
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if
(fsize < 7)
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break
;
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buf2 += fsize;
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}
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max_frames =
FFMAX
(max_frames, frames);
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if
(buf == buf0)
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first_frames= frames;
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}
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if
(first_frames>=3)
return
AVPROBE_SCORE_EXTENSION
+ 1;
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else
if
(max_frames>500)
return
AVPROBE_SCORE_EXTENSION
;
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else
if
(max_frames>=3)
return
AVPROBE_SCORE_EXTENSION
/ 2;
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else
if
(max_frames>=1)
return
1;
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else
return
0;
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}
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static
int
adts_aac_read_header
(
AVFormatContext
*s)
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{
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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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st->
codec
->
codec_id
= s->
iformat
->
raw_codec_id
;
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st->
need_parsing
=
AVSTREAM_PARSE_FULL
;
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ff_id3v1_read
(s);
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//LCM of all possible ADTS sample rates
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avpriv_set_pts_info
(st, 64, 1, 28224000);
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return
0;
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}
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AVInputFormat
ff_aac_demuxer
= {
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.
name
=
"aac"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"raw ADTS AAC (Advanced Audio Coding)"
),
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.read_probe =
adts_aac_probe
,
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.read_header =
adts_aac_read_header
,
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.read_packet =
ff_raw_read_partial_packet
,
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.flags =
AVFMT_GENERIC_INDEX
,
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.extensions =
"aac"
,
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.raw_codec_id =
AV_CODEC_ID_AAC
,
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};
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