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
|
/* This audio filter delays the output signal for the different
channels and can be used for simple position panning. Extension for
this filter would be a reverb.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include "af.h"
#define L 65536
#define UPDATEQI(qi) qi=(qi+1)&(L-1)
// Data for specific instances of this filter
typedef struct af_delay_s
{
void* q[AF_NCH]; // Circular queues used for delaying audio signal
int wi[AF_NCH]; // Write index
int ri; // Read index
float d[AF_NCH]; // Delay [ms]
}af_delay_t;
// Initialization and runtime control
static int control(struct af_instance_s* af, int cmd, void* arg)
{
af_delay_t* s = af->setup;
switch(cmd){
case AF_CONTROL_REINIT:{
int i;
// Free prevous delay queues
for(i=0;i<af->data->nch;i++){
if(s->q[i])
free(s->q[i]);
}
af->data->rate = ((af_data_t*)arg)->rate;
af->data->nch = ((af_data_t*)arg)->nch;
af->data->format = ((af_data_t*)arg)->format;
af->data->bps = ((af_data_t*)arg)->bps;
// Allocate new delay queues
for(i=0;i<af->data->nch;i++){
s->q[i] = calloc(L,af->data->bps);
if(NULL == s->q[i])
af_msg(AF_MSG_FATAL,"[delay] Out of memory\n");
}
return control(af,AF_CONTROL_DELAY_LEN | AF_CONTROL_SET,s->d);
}
case AF_CONTROL_COMMAND_LINE:{
int n = 1;
int i = 0;
char* cl = arg;
while(n && i < AF_NCH ){
sscanf(cl,"%f:%n",&s->d[i],&n);
if(n==0 || cl[n-1] == '\0')
break;
cl=&cl[n];
i++;
}
return AF_OK;
}
case AF_CONTROL_DELAY_LEN | AF_CONTROL_SET:{
int i;
if(AF_OK != af_from_ms(AF_NCH, arg, s->wi, af->data->rate, 0.0, 1000.0))
return AF_ERROR;
s->ri = 0;
for(i=0;i<AF_NCH;i++){
af_msg(AF_MSG_DEBUG0,"[delay] Channel %i delayed by %0.3fms\n",
i,clamp(s->d[i],0.0,1000.0));
af_msg(AF_MSG_DEBUG1,"[delay] Channel %i delayed by %i samples\n",
i,s->wi[i]);
}
return AF_OK;
}
case AF_CONTROL_DELAY_LEN | AF_CONTROL_GET:{
int i;
for(i=0;i<AF_NCH;i++){
if(s->ri > s->wi[i])
s->wi[i] = L - (s->ri - s->wi[i]);
else
s->wi[i] = s->wi[i] - s->ri;
}
return af_to_ms(AF_NCH, s->wi, arg, af->data->rate);
}
}
return AF_UNKNOWN;
}
// Deallocate memory
static void uninit(struct af_instance_s* af)
{
int i;
if(af->data)
free(af->data);
for(i=0;i<AF_NCH;i++)
if(((af_delay_t*)(af->setup))->q[i])
free(((af_delay_t*)(af->setup))->q[i]);
if(af->setup)
free(af->setup);
}
// Filter data through filter
static af_data_t* play(struct af_instance_s* af, af_data_t* data)
{
af_data_t* c = data; // Current working data
af_delay_t* s = af->setup; // Setup for this instance
int nch = c->nch; // Number of channels
int len = c->len/c->bps; // Number of sample in data chunk
int ri = 0;
int ch,i;
for(ch=0;ch<nch;ch++){
switch(c->bps){
case 1:{
int8_t* a = c->audio;
int8_t* q = s->q[ch];
int wi = s->wi[ch];
ri = s->ri;
for(i=ch;i<len;i+=nch){
q[wi] = a[i];
a[i] = q[ri];
UPDATEQI(wi);
UPDATEQI(ri);
}
s->wi[ch] = wi;
break;
}
case 2:{
int16_t* a = c->audio;
int16_t* q = s->q[ch];
int wi = s->wi[ch];
ri = s->ri;
for(i=ch;i<len;i+=nch){
q[wi] = a[i];
a[i] = q[ri];
UPDATEQI(wi);
UPDATEQI(ri);
}
s->wi[ch] = wi;
break;
}
case 4:{
int32_t* a = c->audio;
int32_t* q = s->q[ch];
int wi = s->wi[ch];
ri = s->ri;
for(i=ch;i<len;i+=nch){
q[wi] = a[i];
a[i] = q[ri];
UPDATEQI(wi);
UPDATEQI(ri);
}
s->wi[ch] = wi;
break;
}
}
}
s->ri = ri;
return c;
}
// Allocate memory and set function pointers
static int af_open(af_instance_t* af){
af->control=control;
af->uninit=uninit;
af->play=play;
af->mul=1;
af->data=calloc(1,sizeof(af_data_t));
af->setup=calloc(1,sizeof(af_delay_t));
if(af->data == NULL || af->setup == NULL)
return AF_ERROR;
return AF_OK;
}
// Description of this filter
af_info_t af_info_delay = {
"Delay audio filter",
"delay",
"Anders",
"",
AF_FLAGS_REENTRANT,
af_open
};
|
