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
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
|
/*
* Copyright (C) 2003-2011 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.
*/
#include "config.h"
#include "pcm_volume.h"
#include "pcm_utils.h"
#include "audio_format.h"
#include <glib.h>
#include <stdint.h>
#include <string.h>
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "pcm_volume"
static void
pcm_volume_change_8(int8_t *buffer, const int8_t *end, int volume)
{
while (buffer < end) {
int32_t sample = *buffer;
sample = (sample * volume + pcm_volume_dither() +
PCM_VOLUME_1 / 2)
/ PCM_VOLUME_1;
*buffer++ = pcm_range(sample, 8);
}
}
static void
pcm_volume_change_16(int16_t *buffer, const int16_t *end, int volume)
{
while (buffer < end) {
int32_t sample = *buffer;
sample = (sample * volume + pcm_volume_dither() +
PCM_VOLUME_1 / 2)
/ PCM_VOLUME_1;
*buffer++ = pcm_range(sample, 16);
}
}
#ifdef __i386__
/**
* Optimized volume function for i386. Use the EDX:EAX 2*32 bit
* multiplication result instead of emulating 64 bit multiplication.
*/
static inline int32_t
pcm_volume_sample_24(int32_t sample, int32_t volume, G_GNUC_UNUSED int32_t dither)
{
int32_t result;
asm(/* edx:eax = sample * volume */
"imul %2\n"
/* "add %3, %1\n" dithering disabled for now, because we
have no overflow check - is dithering really important
here? */
/* eax = edx:eax / PCM_VOLUME_1 */
"sal $22, %%edx\n"
"shr $10, %1\n"
"or %%edx, %1\n"
: "=a"(result)
: "0"(sample), "r"(volume) /* , "r"(dither) */
: "edx"
);
return result;
}
#endif
static void
pcm_volume_change_24(int32_t *buffer, const int32_t *end, int volume)
{
while (buffer < end) {
#ifdef __i386__
/* assembly version for i386 */
int32_t sample = *buffer;
sample = pcm_volume_sample_24(sample, volume,
pcm_volume_dither());
#else
/* portable version */
int64_t sample = *buffer;
sample = (sample * volume + pcm_volume_dither() +
PCM_VOLUME_1 / 2)
/ PCM_VOLUME_1;
#endif
*buffer++ = pcm_range(sample, 24);
}
}
static void
pcm_volume_change_32(int32_t *buffer, const int32_t *end, int volume)
{
while (buffer < end) {
#ifdef __i386__
/* assembly version for i386 */
int32_t sample = *buffer;
*buffer++ = pcm_volume_sample_24(sample, volume, 0);
#else
/* portable version */
int64_t sample = *buffer;
sample = (sample * volume + pcm_volume_dither() +
PCM_VOLUME_1 / 2)
/ PCM_VOLUME_1;
*buffer++ = pcm_range_64(sample, 32);
#endif
}
}
static void
pcm_volume_change_float(float *buffer, const float *end, float volume)
{
while (buffer < end) {
float sample = *buffer;
sample *= volume;
*buffer++ = sample;
}
}
bool
pcm_volume(void *buffer, size_t length,
enum sample_format format,
int volume)
{
if (volume == PCM_VOLUME_1)
return true;
if (volume <= 0) {
memset(buffer, 0, length);
return true;
}
const void *end = pcm_end_pointer(buffer, length);
switch (format) {
case SAMPLE_FORMAT_UNDEFINED:
case SAMPLE_FORMAT_S24:
case SAMPLE_FORMAT_DSD:
case SAMPLE_FORMAT_DSD_OVER_USB:
/* not implemented */
return false;
case SAMPLE_FORMAT_S8:
pcm_volume_change_8(buffer, end, volume);
return true;
case SAMPLE_FORMAT_S16:
pcm_volume_change_16(buffer, end, volume);
return true;
case SAMPLE_FORMAT_S24_P32:
pcm_volume_change_24(buffer, end, volume);
return true;
case SAMPLE_FORMAT_S32:
pcm_volume_change_32(buffer, end, volume);
return true;
case SAMPLE_FORMAT_FLOAT:
pcm_volume_change_float(buffer, end,
pcm_volume_to_float(volume));
return true;
}
/* unreachable */
assert(false);
return false;
}
|
