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
gsmdec.c
Go to the documentation of this file.
1
/*
2
* RAW GSM demuxer
3
* Copyright (c) 2011 Justin Ruggles
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/channel_layout.h
"
23
#include "
libavutil/mathematics.h
"
24
#include "
libavutil/opt.h
"
25
#include "
avformat.h
"
26
#include "
internal.h
"
27
28
#define GSM_BLOCK_SIZE 33
29
#define GSM_BLOCK_SAMPLES 160
30
#define GSM_SAMPLE_RATE 8000
31
32
typedef
struct
GSMDemuxerContext
{
33
AVClass
*
class
;
34
int
sample_rate
;
35
}
GSMDemuxerContext
;
36
37
static
int
gsm_read_packet
(
AVFormatContext
*
s
,
AVPacket
*
pkt
)
38
{
39
int
ret
,
size
;
40
41
size =
GSM_BLOCK_SIZE
;
42
43
pkt->
pos
=
avio_tell
(s->
pb
);
44
pkt->
stream_index
= 0;
45
46
ret =
av_get_packet
(s->
pb
, pkt, size);
47
if
(ret <
GSM_BLOCK_SIZE
) {
48
av_free_packet
(pkt);
49
return
ret < 0 ? ret :
AVERROR
(EIO);
50
}
51
pkt->
duration
= 1;
52
pkt->
pts
= pkt->
pos
/
GSM_BLOCK_SIZE
;
53
54
return
0;
55
}
56
57
static
int
gsm_read_header
(
AVFormatContext
*
s
)
58
{
59
GSMDemuxerContext
*
c
= s->
priv_data
;
60
AVStream
*st =
avformat_new_stream
(s,
NULL
);
61
if
(!st)
62
return
AVERROR
(ENOMEM);
63
64
st->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
65
st->
codec
->
codec_id
= s->
iformat
->
raw_codec_id
;
66
st->
codec
->
channels
= 1;
67
st->
codec
->
channel_layout
=
AV_CH_LAYOUT_MONO
;
68
st->
codec
->
sample_rate
= c->
sample_rate
;
69
st->
codec
->
bit_rate
=
GSM_BLOCK_SIZE
* 8 * c->
sample_rate
/
GSM_BLOCK_SAMPLES
;
70
71
avpriv_set_pts_info
(st, 64,
GSM_BLOCK_SAMPLES
,
GSM_SAMPLE_RATE
);
72
73
return
0;
74
}
75
76
static
const
AVOption
options
[] = {
77
{
"sample_rate"
,
""
, offsetof(
GSMDemuxerContext
,
sample_rate
),
78
AV_OPT_TYPE_INT
, {.i64 =
GSM_SAMPLE_RATE
}, 1, INT_MAX /
GSM_BLOCK_SIZE
,
79
AV_OPT_FLAG_DECODING_PARAM
},
80
{
NULL
},
81
};
82
83
static
const
AVClass
gsm_class
= {
84
.
class_name
=
"gsm demuxer"
,
85
.item_name =
av_default_item_name
,
86
.option =
options
,
87
.version =
LIBAVUTIL_VERSION_INT
,
88
};
89
90
AVInputFormat
ff_gsm_demuxer
= {
91
.
name
=
"gsm"
,
92
.long_name =
NULL_IF_CONFIG_SMALL
(
"raw GSM"
),
93
.priv_data_size =
sizeof
(
GSMDemuxerContext
),
94
.
read_header
=
gsm_read_header
,
95
.
read_packet
=
gsm_read_packet
,
96
.
flags
=
AVFMT_GENERIC_INDEX
,
97
.extensions =
"gsm"
,
98
.raw_codec_id =
AV_CODEC_ID_GSM
,
99
.priv_class = &gsm_class,
100
};
Generated on Sun Mar 8 2015 02:34:52 for FFmpeg by
1.8.2