example input and output using cpal

src/main.rs

@@ -0,0 +1,61 @@
+use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
+use std::sync::mpsc;
+
+fn main() {
+    let host = cpal::default_host();
+
+    let input_device = host
+        .default_input_device()
+        .expect("no input device available");
+    let output_device = host
+        .default_output_device()
+        .expect("no output device available");
+
+    println!("input device: {}", input_device);
+    println!("output device: {}", output_device);
+
+    let config: cpal::StreamConfig = input_device
+        .default_input_config()
+        .expect("stream config init failed")
+        .into();
+
+    println!("stream config: {:?}", config);
+
+    let latency_ms = 150.0;
+    let latency_frames = (latency_ms / 1000.0) * config.sample_rate as f32;
+    let latency_samples = latency_frames as usize * config.channels as usize;
+    let (tx, rx) = mpsc::sync_channel::<f32>(latency_samples * 2);
+
+    for _ in 0..latency_samples {
+        tx.send(0.0).unwrap();
+    }
+
+    let input_data_fn = move |data: &[f32], _: &cpal::InputCallbackInfo| {
+        for &sample in data {
+            if tx.try_send(sample).is_err() {}
+        }
+    };
+
+    let output_data_fn = move |data: &mut [f32], _: &cpal::OutputCallbackInfo| {
+        for sample in data {
+            *sample = match rx.try_recv() {
+                Ok(s) => s,
+                Err(_) => 0.0,
+            };
+        }
+    };
+
+    let err_fn = |err| eprintln!("stream error: {}", err);
+
+    let input_stream = input_device
+        .build_input_stream(config, input_data_fn, err_fn, None)
+        .expect("building input stream failed");
+    let output_stream = output_device
+        .build_output_stream(config, output_data_fn, err_fn, None)
+        .expect("building output stream failed");
+
+    input_stream.play().expect("failed to play input stream");
+    output_stream.play().expect("failed to play output stream");
+
+    std::thread::sleep(std::time::Duration::from_secs(5));
+}