-
Notifications
You must be signed in to change notification settings - Fork 29
/
autoyoy.go
218 lines (196 loc) · 5.4 KB
/
autoyoy.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
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
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
package effects
import (
"math"
)
/*
* Data structure representing an auto yoy effect.
*/
type autoyoy struct {
unitStruct
envelope float64
buffer []float64
}
/*
* Auto wah audio processing.
*/
func (this *autoyoy) Process(in []float64, out []float64, sampleRate uint32) {
this.mutex.RLock()
follow, _ := this.getDiscreteValue("follow")
levelA, _ := this.getNumericValue("level_1")
levelB, _ := this.getNumericValue("level_2")
depth, _ := this.getNumericValue("depth")
this.mutex.RUnlock()
depthFloat := float64(depth)
depthA := float64(0.0)
depthB := 0.01 * depthFloat
/*
* If the first level is higher than the second, swap both levels and depths around.
*/
if levelA > levelB {
levelA, levelB = levelB, levelA
depthA, depthB = depthB, depthA
}
levelAFloat := float64(levelA)
levelBFloat := float64(levelB)
depthSlope := (depthB - depthA) / (levelBFloat - levelAFloat)
sampleRateFloat := float64(sampleRate)
sampleRateFloatInv := 1.0 / sampleRateFloat
dischargePerSampleEnvelopeArg := -20.0 * sampleRateFloatInv
dischargePerSampleEnvelopeInv := math.Exp(dischargePerSampleEnvelopeArg)
dischargePerSampleEnvelope := 1.0 - dischargePerSampleEnvelopeInv
maxDelaySamplesFloat := math.Floor((0.01 * sampleRateFloat) + 0.5)
maxDelaySamples := int(maxDelaySamplesFloat)
buffer := this.buffer
bufferSize := len(buffer)
/*
* Make sure the buffer has the appropriate size.
*/
if bufferSize != maxDelaySamples {
buffer = make([]float64, maxDelaySamples)
this.buffer = buffer
bufferSize = maxDelaySamples
}
envelope := this.envelope
/*
* Process each sample.
*/
for i, sample := range in {
sampleAbs := math.Abs(sample)
/*
* Follow either level or envelope.
*/
switch follow {
case "envelope":
envelope *= dischargePerSampleEnvelopeInv
/*
* If the absolute value of the current sample exceeds the
* current envelope value, make it the new envelope value.
*/
if sampleAbs > envelope {
envelope = sampleAbs
}
case "level":
diff := sampleAbs - envelope
envelope += diff * dischargePerSampleEnvelope
default:
envelope = 1.0
}
level := factorToDecibels(envelope)
delayFac := 0.0
/*
* Calculate the current delay of the filter as a piecewise
* linear function of the signal level.
*/
if level <= levelAFloat {
delayFac = depthA
} else if level >= levelBFloat {
delayFac = depthB
} else {
excess := level - levelAFloat
delayFac = depthA + (depthSlope * excess)
}
currentDelayTime := 0.01 * delayFac
currentDelaySamples := currentDelayTime * sampleRateFloat
currentDelaySamplesEarly := math.Floor(currentDelaySamples)
currentDelaySamplesLate := math.Ceil(currentDelaySamples)
delayedIdxEarly := i - int(currentDelaySamplesEarly)
delayedIdxLate := i - int(currentDelaySamplesLate)
delayedSampleEarly := float64(0.0)
delayedSampleLate := float64(0.0)
/*
* Check whether the delayed sample can be found in the current input
* signal or the delay buffer.
*/
if delayedIdxEarly >= 0 {
delayedSampleEarly = in[delayedIdxEarly]
} else {
bufferPtr := bufferSize + delayedIdxEarly
delayedSampleEarly = buffer[bufferPtr]
}
/*
* Check whether the delayed sample can be found in the current input
* signal or the delay buffer.
*/
if delayedIdxLate >= 0 {
delayedSampleLate = in[delayedIdxLate]
} else {
bufferPtr := bufferSize + delayedIdxLate
delayedSampleLate = this.buffer[bufferPtr]
}
weightEarly := 1.0 - (currentDelaySamples - currentDelaySamplesEarly)
weightLate := 1.0 - (currentDelaySamplesLate - currentDelaySamples)
delayedSample := (weightEarly * delayedSampleEarly) + (weightLate * delayedSampleLate)
out[i] = (0.5 * sample) + (0.5 * delayedSample)
}
this.envelope = envelope
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 an auto-yoy effects unit.
*/
func createAutoYoy() Unit {
/*
* Create effects unit.
*/
u := autoyoy{
unitStruct: unitStruct{
unitType: UNIT_AUTOYOY,
params: []Parameter{
Parameter{
Name: "follow",
Type: PARAMETER_TYPE_DISCRETE,
PhysicalUnit: "",
Minimum: -1,
Maximum: -1,
NumericValue: -1,
DiscreteValueIndex: 1,
DiscreteValues: []string{
"envelope",
"level",
},
},
Parameter{
Name: "level_1",
Type: PARAMETER_TYPE_NUMERIC,
PhysicalUnit: "dB",
Minimum: -60,
Maximum: 0,
NumericValue: -40,
DiscreteValueIndex: -1,
DiscreteValues: nil,
},
Parameter{
Name: "level_2",
Type: PARAMETER_TYPE_NUMERIC,
PhysicalUnit: "dB",
Minimum: -60,
Maximum: 0,
NumericValue: -10,
DiscreteValueIndex: -1,
DiscreteValues: nil,
},
Parameter{
Name: "depth",
Type: PARAMETER_TYPE_NUMERIC,
PhysicalUnit: "%",
Minimum: 0,
Maximum: 100,
NumericValue: 100,
DiscreteValueIndex: -1,
DiscreteValues: nil,
},
},
},
}
return &u
}