-
Notifications
You must be signed in to change notification settings - Fork 29
/
delay.go
138 lines (123 loc) · 3 KB
/
delay.go
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
package effects
import (
"math"
)
/*
* Data structure representing a delay effect.
*/
type delay struct {
unitStruct
buffer []float64
}
/*
* Delay audio processing.
*/
func (this *delay) Process(in []float64, out []float64, sampleRate uint32) {
this.mutex.RLock()
delayTime, _ := this.getNumericValue("delay_time")
feedback, _ := this.getNumericValue("feedback")
level, _ := this.getNumericValue("level")
this.mutex.RUnlock()
delayTimeFloat := float64(delayTime)
delayTimeSeconds := 0.001 * delayTimeFloat
sampleRateFloat := float64(sampleRate)
delaySamplesFloat := math.Floor((delayTimeSeconds * sampleRateFloat) + 0.5)
delaySamples := int(delaySamplesFloat)
feedbackFactor := decibelsToFactor(feedback)
levelFactor := decibelsToFactor(level)
buffer := this.buffer
bufferSize := len(buffer)
/*
* Make sure the buffer has the appropriate size.
*/
if bufferSize != delaySamples {
buffer = make([]float64, delaySamples)
bufferSize = delaySamples
this.buffer = buffer
}
/*
* Mix the straight output with the delayed signal.
*/
for i, sample := range in {
delayedIdx := i - delaySamples
delayedSample := float64(0.0)
/*
* Check whether the delayed sample can be found in the current input
* signal or the delay buffer.
*/
if delayedIdx >= 0 {
delayedSample = in[delayedIdx]
} else {
bufferPtr := bufferSize + delayedIdx
delayedSample = buffer[bufferPtr]
}
pre := levelFactor * (sample + (feedbackFactor * delayedSample))
/*
* Limit the output signal to the appropriate range.
*/
if pre < -1.0 {
out[i] = -1.0
} else if pre > 1.0 {
out[i] = 1.0
} else {
out[i] = pre
}
}
numSamples := len(in)
boundary := bufferSize - numSamples
/*
* Check whether our buffer is larger than the number of samples processed.
*/
if boundary >= 0 {
copy(buffer[0:boundary], buffer[numSamples:bufferSize])
copy(buffer[boundary:bufferSize], in)
} else {
copy(buffer, in[-boundary:numSamples])
}
}
/*
* Create a delay effects unit.
*/
func createDelay() Unit {
/*
* Create effects unit.
*/
u := delay{
unitStruct: unitStruct{
unitType: UNIT_DELAY,
params: []Parameter{
Parameter{
Name: "delay_time",
Type: PARAMETER_TYPE_NUMERIC,
PhysicalUnit: "ms",
Minimum: 0,
Maximum: 1000,
NumericValue: 200,
DiscreteValueIndex: -1,
DiscreteValues: nil,
},
Parameter{
Name: "feedback",
Type: PARAMETER_TYPE_NUMERIC,
PhysicalUnit: "dB",
Minimum: -60,
Maximum: 0,
NumericValue: -5,
DiscreteValueIndex: -1,
DiscreteValues: nil,
},
Parameter{
Name: "level",
Type: PARAMETER_TYPE_NUMERIC,
PhysicalUnit: "dB",
Minimum: -30,
Maximum: 0,
NumericValue: -5,
DiscreteValueIndex: -1,
DiscreteValues: nil,
},
},
},
}
return &u
}