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
use crate::bufferpool::*;
use crate::flow::*;
use crate::impl_block_trait;
use crate::numbers::*;
use crate::signal::*;
use crate::windowing::{self, Window};
use rustfft::{Fft, FftPlanner};
use tokio::task::spawn;
use std::sync::Arc;
pub struct Fourier<Flt> {
receiver_connector: ReceiverConnector<Signal<Complex<Flt>>>,
sender_connector: SenderConnector<Signal<Complex<Flt>>>,
}
impl_block_trait! { <Flt> Consumer<Signal<Complex<Flt>>> for Fourier<Flt> }
impl_block_trait! { <Flt> Producer<Signal<Complex<Flt>>> for Fourier<Flt> }
impl<Flt> Fourier<Flt>
where
Flt: Float,
{
pub fn new() -> Self {
Self::new_internal(windowing::Rectangular, false)
}
pub fn new_center_dc() -> Self {
Self::new_internal(windowing::Rectangular, true)
}
pub fn with_window<W>(window: W) -> Self
where
W: Window + Send + 'static,
{
Self::new_internal(window, false)
}
pub fn with_window_center_dc<W>(window: W) -> Self
where
W: Window + Send + 'static,
{
Self::new_internal(window, true)
}
fn new_internal<W>(window: W, center_dc: bool) -> Self
where
W: Window + Send + 'static,
{
let (mut receiver, receiver_connector) = new_receiver::<Signal<Complex<Flt>>>();
let (sender, sender_connector) = new_sender::<Signal<Complex<Flt>>>();
spawn(async move {
let mut buf_pool = ChunkBufPool::new();
let mut previous_chunk_len: Option<usize> = None;
let mut fft: Option<Arc<dyn Fft<Flt>>> = Default::default();
let mut scratch: Vec<f64> = Default::default();
let mut window_values: Vec<Flt> = Default::default();
loop {
let Ok(signal) = receiver.recv().await else { return; };
match signal {
Signal::Samples {
sample_rate,
chunk: input_chunk,
} => {
let n: usize = input_chunk.len();
if Some(n) != previous_chunk_len {
fft = Some(FftPlanner::<Flt>::new().plan_fft_forward(n));
scratch.clear();
scratch.reserve_exact(n);
let mut energy: f64 = 0.0;
for idx in 0..n {
let value = window
.relative_value_at(2.0 * (idx as f64 + 0.5) / n as f64 - 1.0);
scratch.push(value);
energy += value * value;
}
let scale: f64 = (n as f64 / energy).sqrt();
window_values.clear();
window_values.reserve_exact(n);
for &value in scratch.iter() {
window_values.push(flt!(value * scale));
}
previous_chunk_len = Some(n);
}
let mut output_chunk = buf_pool.get_with_capacity(input_chunk.len());
output_chunk.extend_from_slice(&input_chunk);
for idx in 0..n {
output_chunk[idx] *= window_values[idx];
}
fft.as_ref().unwrap().process(&mut output_chunk);
if center_dc {
output_chunk.rotate_right(n / 2);
}
let Ok(()) = sender.send(Signal::Samples {
sample_rate,
chunk: output_chunk.finalize(),
}).await
else { return; };
}
event @ Signal::Event { .. } => {
let Ok(()) = sender.send(event).await else { return; };
}
}
}
});
Self {
receiver_connector,
sender_connector,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::tests::assert_approx;
#[tokio::test]
async fn test_fourier() {
let (sender, sender_connector) = new_sender();
let fourier1 = Fourier::<f64>::new();
let fourier2 = Fourier::<f64>::new_center_dc();
let (mut receiver1, receiver1_connector) = new_receiver();
let (mut receiver2, receiver2_connector) = new_receiver();
fourier1.feed_from(&sender_connector);
fourier2.feed_from(&sender_connector);
fourier1.feed_into(&receiver1_connector);
fourier2.feed_into(&receiver2_connector);
sender
.send(Signal::Samples {
sample_rate: 48000.0,
chunk: Chunk::from(vec![
Complex::new(1.0, 0.0),
Complex::new(1.0, 0.0),
Complex::new(1.0, 0.0),
]),
})
.await
.unwrap();
let Signal::Samples { chunk: output1, .. } = receiver1.recv().await.unwrap()
else { panic!(); };
let Signal::Samples { chunk: output2, .. } = receiver2.recv().await.unwrap()
else { panic!(); };
assert_approx(output1[0].re, 3.0);
assert_approx(output1[0].im, 0.0);
assert_approx(output1[1].re, 0.0);
assert_approx(output1[1].im, 0.0);
assert_approx(output1[2].re, 0.0);
assert_approx(output1[2].im, 0.0);
assert_approx(output2[0].re, 0.0);
assert_approx(output2[0].im, 0.0);
assert_approx(output2[1].re, 3.0);
assert_approx(output2[1].im, 0.0);
assert_approx(output2[2].re, 0.0);
assert_approx(output2[2].im, 0.0);
sender
.send(Signal::Samples {
sample_rate: 48000.0,
chunk: Chunk::from(vec![
Complex::new(1.0, 0.0),
Complex::new(1.5, 0.0),
Complex::new(1.0, 0.0),
Complex::new(0.5, 0.0),
]),
})
.await
.unwrap();
let Signal::Samples { chunk: output1, .. } = receiver1.recv().await.unwrap()
else { panic!(); };
let Signal::Samples { chunk: output2, .. } = receiver2.recv().await.unwrap()
else { panic!(); };
assert_approx(output1[0].re, 4.0);
assert_approx(output1[0].im, 0.0);
assert_approx(output1[1].re, 0.0);
assert_approx(output1[1].im, -1.0);
assert_approx(output1[2].re, 0.0);
assert_approx(output1[2].im, 0.0);
assert_approx(output1[3].re, 0.0);
assert_approx(output1[3].im, 1.0);
assert_approx(output2[0].re, 0.0);
assert_approx(output2[0].im, 0.0);
assert_approx(output2[1].re, 0.0);
assert_approx(output2[1].im, 1.0);
assert_approx(output2[2].re, 4.0);
assert_approx(output2[2].im, 0.0);
assert_approx(output2[3].re, 0.0);
assert_approx(output2[3].im, -1.0);
}
}