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use rodio::{Sink, Source};
use rodio::stream::{OutputStreamBuilder, OutputStream};
use cpal::BufferSize;
use crate::audio::{MutableWave, SAMPLE_RATE};
use crate::io::{Audio, Wave};
use crate::logs::{log, LogLevel};
use std::mem;
use std::time::{SystemTime, Duration};
const BUFFER_SIZE: usize = 256;
const RODIO_BUFFER_SIZE: usize = 1024;
const RODIO_BUFFER_SINK_LATE_EXPECTED: f32 = 0.;
const LATE_SPEEDUP_INTENSITY_INV: f32 = 2048.0;
const SPEEDUP_SKIP_LIMIT: f32 = 1.008;
const TIME_RING_BUFFER_SIZE: usize = (SAMPLE_RATE as usize / BUFFER_SIZE) * 10;
struct SpeedFinder {
buf: [SystemTime; TIME_RING_BUFFER_SIZE],
i: usize,
has_circled: bool,
}
impl SpeedFinder {
fn new() -> Self {
Self {
buf: [SystemTime::now(); TIME_RING_BUFFER_SIZE],
i: 0,
has_circled: false,
}
}
fn tick(&mut self) -> Option<f32> {
if self.i >= TIME_RING_BUFFER_SIZE {
self.i = 0;
self.has_circled = true;
}
let previous = self.buf[self.i];
let now = SystemTime::now();
self.buf[self.i] = now;
self.i += 1;
if !self.has_circled {
if self.i == 1 {
return None;
} else {
return Some(now.duration_since(self.buf[0]).unwrap().as_secs_f32() / (self.i - 1) as f32);
}
} else {
return Some(now.duration_since(previous).unwrap().as_secs_f32() / TIME_RING_BUFFER_SIZE as f32);
}
}
}
pub struct RodioAudio {
sink: Sink,
stream: OutputStream,
speed_finder: SpeedFinder,
wave: RodioWave<MutableWave>,
buffer: Box<[f32; BUFFER_SIZE]>,
buffer_i: usize,
}
struct RodioWave<W: Wave + Send + 'static>(W, usize);
impl<W: Wave + Send + 'static> Iterator for RodioWave<W> {
type Item = f32;
fn next(&mut self) -> Option<Self::Item> {
self.1 += 1;
let left = self.1 % 2 == 0;
let result = self.0.next(left);
result
}
}
struct RodioBuffer<I: Iterator<Item = f32>>(I);
impl<I: Iterator<Item = f32>> Iterator for RodioBuffer<I> {
type Item = f32;
fn next(&mut self) -> Option<Self::Item> {
self.0.next()
}
}
impl<I: Iterator<Item = f32>> Source for RodioBuffer<I> {
fn current_span_len(&self) -> Option<usize> {
None
}
fn channels(&self) -> u16 {
2
}
fn sample_rate(&self) -> u32 {
SAMPLE_RATE
}
fn total_duration(&self) -> Option<Duration> {
None
}
}
impl Audio for RodioAudio {
fn new(wave: MutableWave) -> Self {
let stream = OutputStreamBuilder::from_default_device().unwrap().with_sample_rate(SAMPLE_RATE).with_buffer_size(BufferSize::Fixed(RODIO_BUFFER_SIZE as u32)).open_stream().unwrap();
let sink = Sink::connect_new(stream.mixer());
let wave = RodioWave(wave, 0);
RodioAudio {
speed_finder: SpeedFinder::new(),
sink: sink,
wave,
buffer: Box::new([0.0; BUFFER_SIZE]),
buffer_i: 0,
stream,
}
}
fn next(&mut self) {
if let Some(v) = self.wave.next() {
self.buffer[self.buffer_i] = v;
self.buffer_i += 1;
if self.buffer_i == BUFFER_SIZE {
self.buffer_i = 0;
let mut buffer = Box::new([0.0; BUFFER_SIZE]);
mem::swap(&mut self.buffer, &mut buffer);
if let Some(speed) = self.speed_finder.tick() {
let mut late_speedup: f32;
let rodio_buffers_sink_late = self.sink.len() as f32 / (RODIO_BUFFER_SIZE / BUFFER_SIZE) as f32;
late_speedup = ((rodio_buffers_sink_late - RODIO_BUFFER_SINK_LATE_EXPECTED).powi(3) / LATE_SPEEDUP_INTENSITY_INV) + 1.;
if late_speedup > SPEEDUP_SKIP_LIMIT {
while late_speedup > 1.0 {
let rodio_buffers_sink_late = self.sink.len() as f32 / (RODIO_BUFFER_SIZE / BUFFER_SIZE) as f32;
late_speedup = ((rodio_buffers_sink_late - RODIO_BUFFER_SINK_LATE_EXPECTED).powi(3) / LATE_SPEEDUP_INTENSITY_INV) + 1.;
self.sink.skip_one();
}
late_speedup = 1.;
}
let average_speed = (1./speed) / (2 * SAMPLE_RATE / BUFFER_SIZE as u32) as f32;
let rodio_buffers_sink_late = self.sink.len() as f32 / (RODIO_BUFFER_SIZE / BUFFER_SIZE) as f32;
log(LogLevel::AudioLatency, format!("audio sink latency: {}ms", (1000. * rodio_buffers_sink_late / ((2*SAMPLE_RATE) as f32 / RODIO_BUFFER_SIZE as f32))));
self.sink.set_speed(late_speedup * average_speed);
}
self.sink.append(RodioBuffer(buffer.into_iter()));
}
}
}
}
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