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use std::{io::Write, slice};
fn main() {
let freq_ampl_pairs : Vec<String> = std::env::args()
.skip(1)
.collect();
let freq_ampl : Vec<(f32, f32)> = freq_ampl_pairs
.chunks_exact(2)
.map(|c| {
(c[0].parse().expect("argument should convert to 32"),
c[1].parse().expect("argument should convert to 32"))
})
.collect();
println!("PDM gen with:");
for (f, a) in &freq_ampl {
println!("Freq: {} Ampl: {}", f, a);
}
const AUDIO_RATE : usize = 31250;
const INTERP : usize = 64;
//const PDM_RATE : usize = AUDIO_RATE * INTERP;
const AUDIO_LEN : usize = 2 * AUDIO_RATE;
let mut audio_signal = Vec::new();
audio_signal.resize(AUDIO_LEN, 0f32);
use std::f32::consts::PI;
for (f, a) in &freq_ampl {
for n in 0..AUDIO_LEN {
audio_signal[n] += a * f32::sin(2.0 * PI * f / (AUDIO_RATE as f32) * (n as f32));
}
}
let mut pdm_signal = Vec::with_capacity(audio_signal.len() * INTERP);
for samp in audio_signal {
let mut quant = 0i8;
let mut sigma = 0.0;
for _i in 0..INTERP {
let delta = samp - quant as f32;
sigma += delta;
quant = if sigma >= 0.0 { 1 } else { -1 };
pdm_signal.push(quant);
}
}
let fd = std::fs::File::create("pdm.npy").expect("pdm.npy should be created");
let mut fd = std::io::BufWriter::new(fd);
let slice_u8: &[u8] = unsafe {
slice::from_raw_parts(
pdm_signal.as_ptr() as *const u8,
pdm_signal.len(),
)
};
fd.write(slice_u8).expect("write to pdm.npy");
let fd = std::fs::File::create("pdm.hex").expect("pdm.hex should be created");
let mut fd = std::io::BufWriter::new(fd);
for samp in pdm_signal {
writeln!(&mut fd, "{}", if samp > 0 { 1 } else { 0 }).expect("write to pdm.hex");
}
}
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