cpal/examples/record_wav.rs

110 lines
4.4 KiB
Rust

//! Records a WAV file (roughly 3 seconds long) using the default input device and format.
//!
//! The input data is recorded to "$CARGO_MANIFEST_DIR/recorded.wav".
extern crate anyhow;
extern crate cpal;
extern crate hound;
use cpal::traits::{DeviceTrait, EventLoopTrait, HostTrait};
fn main() -> Result<(), anyhow::Error> {
// Use the default host for working with audio devices.
let host = cpal::default_host();
// Setup the default input device and stream with the default input format.
let device = host.default_input_device().expect("Failed to get default input device");
println!("Default input device: {}", device.name()?);
let format = device.default_input_format().expect("Failed to get default input format");
println!("Default input format: {:?}", format);
let event_loop = host.event_loop();
let stream_id = event_loop.build_input_stream(&device, &format)?;
event_loop.play_stream(stream_id)?;
// The WAV file we're recording to.
const PATH: &'static str = concat!(env!("CARGO_MANIFEST_DIR"), "/recorded.wav");
let spec = wav_spec_from_format(&format);
let writer = hound::WavWriter::create(PATH, spec)?;
let writer = std::sync::Arc::new(std::sync::Mutex::new(Some(writer)));
// A flag to indicate that recording is in progress.
println!("Begin recording...");
let recording = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(true));
// Run the input stream on a separate thread.
let writer_2 = writer.clone();
let recording_2 = recording.clone();
std::thread::spawn(move || {
event_loop.run(move |id, event| {
let data = match event {
Ok(data) => data,
Err(err) => {
eprintln!("an error occurred on stream {:?}: {}", id, err);
return;
}
};
// If we're done recording, return early.
if !recording_2.load(std::sync::atomic::Ordering::Relaxed) {
return;
}
// Otherwise write to the wav writer.
match data {
cpal::StreamData::Input { buffer: cpal::UnknownTypeInputBuffer::U16(buffer) } => {
if let Ok(mut guard) = writer_2.try_lock() {
if let Some(writer) = guard.as_mut() {
for sample in buffer.iter() {
let sample = cpal::Sample::to_i16(sample);
writer.write_sample(sample).ok();
}
}
}
},
cpal::StreamData::Input { buffer: cpal::UnknownTypeInputBuffer::I16(buffer) } => {
if let Ok(mut guard) = writer_2.try_lock() {
if let Some(writer) = guard.as_mut() {
for &sample in buffer.iter() {
writer.write_sample(sample).ok();
}
}
}
},
cpal::StreamData::Input { buffer: cpal::UnknownTypeInputBuffer::F32(buffer) } => {
if let Ok(mut guard) = writer_2.try_lock() {
if let Some(writer) = guard.as_mut() {
for &sample in buffer.iter() {
writer.write_sample(sample).ok();
}
}
}
},
_ => (),
}
});
});
// Let recording go for roughly three seconds.
std::thread::sleep(std::time::Duration::from_secs(3));
recording.store(false, std::sync::atomic::Ordering::Relaxed);
writer.lock().unwrap().take().unwrap().finalize()?;
println!("Recording {} complete!", PATH);
Ok(())
}
fn sample_format(format: cpal::SampleFormat) -> hound::SampleFormat {
match format {
cpal::SampleFormat::U16 => hound::SampleFormat::Int,
cpal::SampleFormat::I16 => hound::SampleFormat::Int,
cpal::SampleFormat::F32 => hound::SampleFormat::Float,
}
}
fn wav_spec_from_format(format: &cpal::Format) -> hound::WavSpec {
hound::WavSpec {
channels: format.channels as _,
sample_rate: format.sample_rate.0 as _,
bits_per_sample: (format.data_type.sample_size() * 8) as _,
sample_format: sample_format(format.data_type),
}
}