1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
/*
DeaDBeeF - ultimate music player for GNU/Linux systems with X11
Copyright (C) 2009-2013 Alexey Yakovenko <waker@users.sourceforge.net>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <stdio.h>
#include "aac_parser.h"
#define min(x,y) ((x)<(y)?(x):(y))
#define max(x,y) ((x)>(y)?(x):(y))
//#define trace(...) { fprintf(stderr, __VA_ARGS__); }
#define trace(fmt,...)
static const int aac_sample_rates[16] = {
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000, 7350
};
static const int aac_channels[8] = {
0, 1, 2, 3, 4, 5, 6, 8
};
int
aac_sync(const uint8_t *buf, int *channels, int *sample_rate, int *bit_rate, int *samples)
{
int size, rdb;
// 12 sync bits
if (buf[0] != 0xff || (buf[1]&0xf0) != 0xf0) {
//trace ("unsync\n");
return 0;
}
int id = (buf[1] & 0x08) >> 7;
int version = id == 0 ? 4 : 2;
int layer = (buf[1] & 0x06) >> 5;
int protection_abs = (buf[1] & 0x01);
int header_size = protection_abs > 0 ? 7 : 9;
int profile_objecttype = (buf[2] & 0xC0) >> 6;
const char *profiles[4] = {
"0 Main profile AAC MAIN",
"1 Low Complexity profile (LC)AAC LC",
"2 Scalable Sample Rate profile (SSR)AAC SSR",
"3 (reserved)AAC LTP"
};
trace ("profile: %s\n", profiles[profile_objecttype]);
int sample_freq_index = (buf[2] & 0x3C) >> 2;
if (!aac_sample_rates[sample_freq_index]) {
//trace ("invalid samplerate\n");
return 0;
}
trace ("samplerate %d (#%d)\n", aac_sample_rates[sample_freq_index], sample_freq_index);
int private_bit = (buf[2] & 0x02) >> 1;
int channel_conf = ((buf[2] & 0x01) << 2) | ((buf[3] & 0xC0) >> 6);
if (!aac_channels[channel_conf]) {
//trace ("invalid channels\n");
return 0;
}
trace ("channels %d (#%d)\n", aac_channels[channel_conf], channel_conf);
int orig_copy = (buf[3] & 0x20) >> 5;
int home = (buf[3] & 0x10) >> 4;
int copyright_ident_bit = (buf[3] & 0x08) >> 3;
int copyright_ident_start = (buf[3] & 0x04) >> 2;
size = ((buf[3] & 0x03) << 11) | (buf[4] << 3) | ((buf[5] & 0xE0) >> 5);
if(size < ADTS_HEADER_SIZE) {
//trace ("invalid size\n");
return 0;
}
int adts_buffer_fullness = ((buf[5] & 0x1F) << 3) | ((buf[6] & 0xFC) >> 2);
rdb = buf[6] & 0x03;
if (!rdb) {
rdb = buf[7] & 0x03;
}
trace ("rdb: %d\n", rdb);
*channels = aac_channels[channel_conf];
*sample_rate = aac_sample_rates[sample_freq_index];
*samples = rdb * 1024;
if (*channels <= 0 || *sample_rate <= 0 || *samples <= 0) {
return 0;
}
*bit_rate = size * 8 * *sample_rate / *samples;
return size;
}
|
