FFmpeg
Main Page
Related Pages
Modules
Namespaces
Data Structures
Files
Examples
File List
Globals
•
All
Data Structures
Namespaces
Files
Functions
Variables
Typedefs
Enumerations
Enumerator
Macros
Groups
Pages
libavformat
loasdec.c
Go to the documentation of this file.
1
/*
2
* LOAS AudioSyncStream demuxer
3
* Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4
*
5
* This file is part of FFmpeg.
6
*
7
* FFmpeg is free software; you can redistribute it and/or
8
* modify it under the terms of the GNU Lesser General Public
9
* License as published by the Free Software Foundation; either
10
* version 2.1 of the License, or (at your option) any later version.
11
*
12
* FFmpeg is distributed in the hope that it will be useful,
13
* but WITHOUT ANY WARRANTY; without even the implied warranty of
14
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15
* Lesser General Public License for more details.
16
*
17
* You should have received a copy of the GNU Lesser General Public
18
* License along with FFmpeg; if not, write to the Free Software
19
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
*/
21
22
#include "
libavutil/intreadwrite.h
"
23
#include "
libavutil/internal.h
"
24
#include "
avformat.h
"
25
#include "
internal.h
"
26
#include "
rawdec.h
"
27
28
#define LOAS_SYNC_WORD 0x2b7
29
30
static
int
loas_probe
(
AVProbeData
*p)
31
{
32
int
max_frames = 0, first_frames = 0;
33
int
fsize, frames;
34
const
uint8_t
*buf0 = p->
buf
;
35
const
uint8_t
*buf2;
36
const
uint8_t
*
buf
;
37
const
uint8_t
*
end
= buf0 + p->
buf_size
- 3;
38
buf = buf0;
39
40
for
(; buf <
end
; buf = buf2 + 1) {
41
buf2 =
buf
;
42
43
for
(frames = 0; buf2 <
end
; frames++) {
44
uint32_t
header
=
AV_RB24
(buf2);
45
if
((header >> 13) !=
LOAS_SYNC_WORD
)
46
break
;
47
fsize = (header & 0x1FFF) + 3;
48
if
(fsize < 7)
49
break
;
50
fsize =
FFMIN
(fsize, end - buf2);
51
buf2 += fsize;
52
}
53
max_frames =
FFMAX
(max_frames, frames);
54
if
(buf == buf0)
55
first_frames = frames;
56
}
57
58
if
(first_frames >= 3)
59
return
AVPROBE_SCORE_EXTENSION
+ 1;
60
else
if
(max_frames > 100)
61
return
AVPROBE_SCORE_EXTENSION
;
62
else
if
(max_frames >= 3)
63
return
AVPROBE_SCORE_EXTENSION
/ 2;
64
else
65
return
0;
66
}
67
68
static
int
loas_read_header
(
AVFormatContext
*
s
)
69
{
70
AVStream
*st;
71
72
st =
avformat_new_stream
(s,
NULL
);
73
if
(!st)
74
return
AVERROR
(ENOMEM);
75
76
st->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
77
st->
codec
->
codec_id
= s->
iformat
->
raw_codec_id
;
78
st->
need_parsing
=
AVSTREAM_PARSE_FULL_RAW
;
79
80
//LCM of all possible AAC sample rates
81
avpriv_set_pts_info
(st, 64, 1, 28224000);
82
83
return
0;
84
}
85
86
AVInputFormat
ff_loas_demuxer
= {
87
.
name
=
"loas"
,
88
.long_name =
NULL_IF_CONFIG_SMALL
(
"LOAS AudioSyncStream"
),
89
.read_probe =
loas_probe
,
90
.read_header =
loas_read_header
,
91
.read_packet =
ff_raw_read_partial_packet
,
92
.flags=
AVFMT_GENERIC_INDEX
,
93
.raw_codec_id =
AV_CODEC_ID_AAC_LATM
,
94
};
Generated on Sun Mar 8 2015 02:35:10 for FFmpeg by
1.8.2