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extern crate rustfft;
extern crate num;
use std::f64::consts::PI;
use std::collections::VecDeque;
use num::{Float, Complex, FromPrimitive, ToPrimitive};
#[allow(non_camel_case_types)]
type c64 = Complex<f64>;
#[derive(Copy, Clone)]
pub struct Bin {
pub freq: f64,
pub amp: f64,
}
impl Bin {
pub fn new(freq: f64, amp: f64) -> Bin {
Bin {
freq: freq,
amp: amp,
}
}
}
pub struct PhaseVocoder {
channels: usize,
sample_rate: f64,
frame_size: usize,
time_res: usize,
samples_waiting: usize,
in_buf: Vec<VecDeque<f64>>,
out_buf: Vec<VecDeque<f64>>,
last_phase: Vec<Vec<f64>>,
sum_phase: Vec<Vec<f64>>,
output_accum: Vec<VecDeque<f64>>,
forward_fft: rustfft::FFT<f64>,
backward_fft: rustfft::FFT<f64>,
}
impl PhaseVocoder {
pub fn new(channels: usize,
sample_rate: f64,
freq_res: usize,
time_res: usize)
-> PhaseVocoder {
let frame_size = 1 << freq_res;
PhaseVocoder {
channels: channels,
sample_rate: sample_rate,
frame_size: frame_size,
time_res: time_res,
samples_waiting: 0,
in_buf: vec![VecDeque::new(); channels],
out_buf: vec![VecDeque::new(); channels],
last_phase: vec![vec![0.0; frame_size]; channels],
sum_phase: vec![vec![0.0; frame_size]; channels],
output_accum: vec![VecDeque::new(); channels],
forward_fft: rustfft::FFT::new(frame_size, false),
backward_fft: rustfft::FFT::new(frame_size, true),
}
}
pub fn process<S, F>(&mut self, input: &[&[S]], output: &mut [&mut [S]], processor: F)
where S: Float + ToPrimitive + FromPrimitive,
F: Fn(usize, usize, &[Vec<Bin>], &mut [Vec<Bin>])
{
assert_eq!(input.len(), self.channels);
assert_eq!(output.len(), self.channels);
for chan in 0..input.len() {
for samp in 0..input[chan].len() {
self.in_buf[chan].push_back(input[chan][samp].to_f64().unwrap());
self.samples_waiting += 1;
}
}
while self.samples_waiting >= 2 * self.frame_size * self.channels {
let frame_size = self.frame_size;
let step_size = frame_size / self.time_res;
let expect = 2.0 * PI * (step_size as f64) / (frame_size as f64);
let freq_per_bin = self.sample_rate / (frame_size as f64);
for _ in 0..self.time_res {
let mut analysis_out = vec![vec![Bin::new(0.0, 0.0); frame_size]; self.channels];
let mut synthesis_in = vec![vec![Bin::new(0.0, 0.0); frame_size]; self.channels];
for chan in 0..self.channels {
let samples = &self.in_buf[chan];
let mut last_phase = &mut self.last_phase[chan];
let mut fft_in = vec![c64::new(0.0, 0.0); frame_size];
let mut fft_out = vec![c64::new(0.0, 0.0); frame_size];
for i in 0..frame_size {
let window = window((i as f64) / (frame_size as f64));
fft_in[i] = c64::new(samples[i] * window, 0.0);
}
self.forward_fft.process(&fft_in, &mut fft_out);
for i in 0..frame_size {
let x = fft_out[i];
let (amp, phase) = x.to_polar();
let mut tmp = phase - last_phase[i];
last_phase[i] = phase;
tmp -= (i as f64) * expect;
let mut qpd = (tmp / PI) as i32;
if qpd >= 0 {
qpd += qpd & 1;
} else {
qpd -= qpd & 1;
}
tmp -= PI * (qpd as f64);
tmp = (self.time_res as f64) * tmp / (2.0 * PI);
tmp = (i as f64) * freq_per_bin + tmp * freq_per_bin;
analysis_out[chan][i] = Bin::new(tmp, amp * 2.0);
}
}
processor(self.channels, frame_size, &analysis_out, &mut synthesis_in);
for chan in 0..self.channels {
let mut sum_phase = &mut self.sum_phase[chan];
let mut fft_in = vec![c64::new(0.0, 0.0); frame_size];
let mut fft_out = vec![c64::new(0.0, 0.0); frame_size];
for i in 0..frame_size {
let amp = synthesis_in[chan][i].amp;
let mut tmp = synthesis_in[chan][i].freq;
tmp -= (i as f64) * freq_per_bin;
tmp /= freq_per_bin;
tmp = 2.0 * PI * tmp / (self.time_res as f64);
tmp += (i as f64) * expect;
sum_phase[i] += tmp;
let phase = sum_phase[i];
fft_in[i] = c64::from_polar(&, &phase);
}
self.backward_fft.process(&fft_in, &mut fft_out);
for i in 0..frame_size {
let window = window((i as f64) / (frame_size as f64));
if i == self.output_accum[chan].len() {
self.output_accum[chan].push_back(0.0);
}
self.output_accum[chan][i] += window * fft_out[i].re /
((frame_size as f64) *
(self.time_res as f64));
}
for _ in 0..step_size {
self.out_buf[chan].push_back(self.output_accum[chan].pop_front().unwrap());
self.in_buf[chan].pop_front();
}
}
}
self.samples_waiting -= self.frame_size * self.channels;
}
for chan in 0..self.channels {
for samp in 0..output[chan].len() {
output[chan][samp] = match self.out_buf[chan].pop_front() {
Some(x) => FromPrimitive::from_f64(x).unwrap(),
None => break,
}
}
}
}
}
fn window(x: f64) -> f64 {
-0.5 * (2.0 * PI * x).cos() + 0.5
}