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
|
/***************************************************************************
Normalizer.cpp - simple normalizer with limiter
-------------------
begin : Sat May 09 2009
copyright : (C) 2009 by Thomas Eschenbacher
email : Thomas.Eschenbacher@gmx.de
limiter function : (C) 1999-2005 Chris Vaill <chrisvaill at gmail>
taken from "normalize-0.7.7"
***************************************************************************/
/***************************************************************************
* *
* 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. *
* *
***************************************************************************/
#include "config.h"
#include <math.h>
#include "libkwave/Sample.h"
#include "Normalizer.h"
//***************************************************************************
Kwave::Normalizer::Normalizer()
:Kwave::SampleSource(nullptr), m_gain(1.0), m_limit(0.5)
{
}
//***************************************************************************
Kwave::Normalizer::~Normalizer()
{
}
//***************************************************************************
void Kwave::Normalizer::goOn()
{
}
//***************************************************************************
/*
* Limiter function:
*
* / tanh((x + lev) / (1-lev)) * (1-lev) - lev (for x < -lev)
* |
* x' = | x (for |x| <= lev)
* |
* \ tanh((x - lev) / (1-lev)) * (1-lev) + lev (for x > lev)
*
* With limiter level = 0, this is equivalent to a tanh() function;
* with limiter level = 1, this is equivalent to clipping.
*/
static inline double limiter(const double x, const double lmtr_lvl)
{
double xp;
if (x < -lmtr_lvl)
xp = tanh((x + lmtr_lvl) / (1-lmtr_lvl)) * (1-lmtr_lvl) - lmtr_lvl;
else if (x <= lmtr_lvl)
xp = x;
else
xp = tanh((x - lmtr_lvl) / (1-lmtr_lvl)) * (1-lmtr_lvl) + lmtr_lvl;
return xp;
}
//***************************************************************************
void Kwave::Normalizer::input(Kwave::SampleArray data)
{
const unsigned int len = data.size();
const bool use_limiter = (m_gain > 1.0);
for (unsigned int i = 0; i < len; i++) {
double s = sample2double(data[i]);
s *= m_gain;
if (use_limiter) s = limiter(s, m_limit);
data[i] = double2sample(s);
}
emit output(data);
}
//***************************************************************************
void Kwave::Normalizer::setGain(const QVariant g)
{
m_gain = QVariant(g).toDouble();
}
//***************************************************************************
void Kwave::Normalizer::setLimiterLevel(const QVariant l)
{
m_limit = QVariant(l).toDouble();
}
//***************************************************************************
//***************************************************************************
#include "moc_Normalizer.cpp"
|
