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
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
/*
* Copyright (C) 2003-2014 The Music Player Daemon Project
* http://www.musicpd.org
*
* 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.
*/
#ifndef MPD_PCM_VOLUME_HXX
#define MPD_PCM_VOLUME_HXX
#include "AudioFormat.hxx"
#include "PcmBuffer.hxx"
#include "PcmDither.hxx"
#include <stdint.h>
#include <stddef.h>
#ifndef NDEBUG
#include <assert.h>
#endif
class Error;
template<typename T> struct ConstBuffer;
/**
* Number of fractional bits for a fixed-point volume value.
*/
static constexpr unsigned PCM_VOLUME_BITS = 10;
/**
* This value means "100% volume".
*/
static constexpr unsigned PCM_VOLUME_1 = 1024;
static constexpr int PCM_VOLUME_1S = PCM_VOLUME_1;
struct AudioFormat;
/**
* Converts a float value (0.0 = silence, 1.0 = 100% volume) to an
* integer volume value (1000 = 100%).
*/
static inline int
pcm_float_to_volume(float volume)
{
return volume * PCM_VOLUME_1 + 0.5;
}
static inline float
pcm_volume_to_float(int volume)
{
return (float)volume / (float)PCM_VOLUME_1;
}
/**
* A class that converts samples from one format to another.
*/
class PcmVolume {
SampleFormat format;
unsigned volume;
PcmBuffer buffer;
PcmDither dither;
public:
PcmVolume()
:volume(PCM_VOLUME_1) {
#ifndef NDEBUG
format = SampleFormat::UNDEFINED;
#endif
}
#ifndef NDEBUG
~PcmVolume() {
assert(format == SampleFormat::UNDEFINED);
}
#endif
unsigned GetVolume() const {
return volume;
}
/**
* @param _volume the volume level in the range
* [0..#PCM_VOLUME_1]; may be bigger than #PCM_VOLUME_1, but
* then it will most likely clip a lot
*/
void SetVolume(unsigned _volume) {
volume = _volume;
}
/**
* Opens the object, prepare for Apply().
*
* @param format the sample format
* @param error location to store the error
* @return true on success
*/
bool Open(SampleFormat format, Error &error);
/**
* Closes the object. After that, you may call Open() again.
*/
void Close() {
#ifndef NDEBUG
assert(format != SampleFormat::UNDEFINED);
format = SampleFormat::UNDEFINED;
#endif
}
/**
* Apply the volume level.
*/
gcc_pure
ConstBuffer<void> Apply(ConstBuffer<void> src);
};
#endif
|
