blob: 8c31cae92fecf6cfd7fe1432ba78aeb59a3100ce (
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
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
|
/* This audio output plugin changes the volume of the sound, and can
be used when the mixer doesn't support the PCM channel. The volume
is set in fixed steps between 0 - 2^8. */
#define PLUGIN
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
#include "audio_out.h"
#include "audio_plugin.h"
#include "audio_plugin_internal.h"
#include "afmt.h"
static ao_info_t info =
{
"Volume control audio plugin",
"volume",
"Anders",
""
};
LIBAO_PLUGIN_EXTERN(volume)
// local data
typedef struct pl_volume_s
{
uint16_t volume; // output volume level
int inuse; // This plugin is in use TRUE, FALSE
int format; // sample fomat
} pl_volume_t;
static pl_volume_t pl_volume={0,0,0};
// to set/get/query special features/parameters
static int control(int cmd,int arg){
switch(cmd){
case AOCONTROL_PLUGIN_SET_LEN:
return CONTROL_OK;
case AOCONTROL_GET_VOLUME:{
if(pl_volume.inuse){
((ao_control_vol_t *)arg)->right=((float)pl_volume.volume)/2.55;
((ao_control_vol_t *)arg)->left=((float)pl_volume.volume)/2.55;
return CONTROL_OK;
}
else
return CONTROL_ERROR;
}
case AOCONTROL_SET_VOLUME:{
if(pl_volume.inuse){
// Calculate avarage between left and right
float vol =2.55*((((ao_control_vol_t *)arg)->right)+(((ao_control_vol_t *)arg)->left))/2;
pl_volume.volume=(uint16_t)vol;
// Volume must be between 0 and 255
if(vol > 255)
pl_volume.volume = 0xFF;
if(vol < 0)
pl_volume.volume = 0;
return CONTROL_OK;
}
else
return CONTROL_ERROR;
}
}
return CONTROL_UNKNOWN;
}
// open & setup audio device
// return: 1=success 0=fail
static int init(){
// Sanity sheck this plugin supports AFMT_U8 and AFMT_S16_LE
switch(ao_plugin_data.format){
case(AFMT_U8):
case(AFMT_S16_LE):
break;
default:
fprintf(stderr,"[pl_volume] Audio format not yet suported \n");
return 0;
}
// Initialize volume to this value
pl_volume.volume=ao_plugin_cfg.pl_volume_volume;
pl_volume.format=ao_plugin_data.format;
/* The inuse flag is used in control to detremine if the return
value since that function always is called from ao_plugin regardless
of wether this plugin is in use or not. */
pl_volume.inuse=1;
// Tell the world what we are up to
printf("[pl_volume] Software volume control in use.\n");
return 1;
}
// close plugin
static void uninit(){
pl_volume.inuse=0;
}
// empty buffers
static void reset(){
}
// processes 'ao_plugin_data.len' bytes of 'data'
// called for every block of data
static int play(){
register int i=0;
// Change the volume.
switch(pl_volume.format){
case(AFMT_U8):{
register uint8_t* data=(uint8_t*)ao_plugin_data.data;
for(i=0;i<ao_plugin_data.len;i++){
data[i]=(((data[i]-128) * pl_volume.volume) >> 8) + 128;
}
break;
}
case(AFMT_S16_LE):{
register int len=ao_plugin_data.len>>1;
register int16_t* data=(int16_t*)ao_plugin_data.data;
for(i=0;i<len;i++)
data[i]=(data[i]* pl_volume.volume)>>8;
break;
}
default:
return 0;
}
return 1;
}
|
