blob: 2f4df71e6975f98a949249d4cc1b650e9f7c11bf (
plain)
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
|
/**
* aweight.h - Efficient A-weighting algorithm
* Copyright (C) 2024 Clyne Sullivan <clyne@bitgloo.com>
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 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 Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef AWEIGHT_H
#define AWEIGHT_H
/**
* Applies A-weighting to the given audio sample.
* @param in_div4 The audio sample divided by four
* @return The filtered (A-weighted) sample
*/
inline float process(float in_div4)
{
static float z1 = 0, z2 = 0, z3 = 0, z5 = 0;
float out1 = in_div4 + z1;
z1 = 1.062f * out1 + z2;
z2 = -0.14f * out1 - in_div4;
float out2 = out1 + z3;
z3 = out1;
float out3 = out2 + z5;
z5 = 0.985f * out3 - out2;
return out3;
}
#endif // AWEIGHT_H
|
