cpal/examples/record_wav.rs

96 lines
4.0 KiB
Rust
Raw Normal View History

Update to a more general Device and Stream API. Add support for input streams (E.g. microphone). Add default format methods. (#201) * Update to a more general Device and Stream API This update prepares for adding input stream support by removing the `Endpoint` type (which only supports output streams) in favour of a more general `Device` type which may support any number of input or output streams. Previously discussed at #117. The name `Voice` has been replaced with the more ubiquitous name `Stream`. See #118 for justification. Also introduces a new `StreamData` which is now passed to the `EventLoop::run` callback rather than the `UnknownTypeBuffer`. `StreamData` allows for passing either `Input` data to be read, or `Output` data to be written. The `beep.rs` example has been updated for the API changes. None of the backends have been updated for this API change yet. Backends will be updated in the following commits. Closes #117. Closes #118. * Update ALSA backend for new `Device` and `Stream` API. * Update wasapi backend for new `Device` and `Stream` API. * Update enumerate.rs example for new `Device` and `Stream` API. * Update coreaudio backend for new `Device` and `Stream` API. * Fix lib doc tests for Device and Stream API update * Update emscripten backend for new `Device` and `Stream` API. * Update null backend for new `Device` and `Stream` API. * Merge match exprs in beep.rs example * Add Input variant along with UnknownTypeInputBuffer and InputBuffer UnknownTypeBuffer and Buffer have been renamed to UnknownTypeOutputBuffer and OutputBuffer respectively. No backends have yet been updated for this name change or the addition of the InputBuffer. * Update null backend for introduction of InputBuffer * Update emscripten backend for introduction of InputBuffer * Make InputBuffer inner field an option to call finish in drop * Update alsa backend for introduction of InputBuffer * Update wasapi backend for introduction of InputBuffer * Update coreaudio backend for introduction of InputBuffer * Update enumerate.rs example to provide more detail about devices The enumerate.rs example now also displays: - Supported input stream formats. - Default input stream format. - Default output stream format. This should also be useful for testing the progress of #201. * Add `record_wav.rs` example for demonstrating input streams Records a ~3 second WAV file to `$CARGO_MANIFEST_DIR/recorded.wav` using the default input device and default input format. Uses hound 3.0 to create and write to the WAV file. This should also be useful for testing the input stream implementations for each different cpal backend. * Implement input stream support for coreaudio backend This implements the following for the coreaudio backend: - Device::supported_input_formats - Device::default_input_format - Device::default_output_format - EventLoop::build_input_stream The `enumerate.rs` and `record_wav.rs` examples now work successfully on macos. * Add `SupportedFormat::cmp_default_heuristics` method This adds a comparison function which compares two `SupportedFormat`s in terms of their priority of use as a default stream format. Some backends (such as ALSA) do not provide a default stream format for their audio devices. In these cases, CPAL attempts to decide on a reasonable default format for the user. To do this we use the "greatest" of all supported stream formats when compared with this method. * Implement input stream support for ALSA backend This implements the following for the ALSA backend: - Device::supported_input_formats - Device::default_input_format - Device::default_output_format - EventLoop::build_input_stream Note that ALSA itself does not give default stream formats for its devices. Thus the newly added `SupportedFormat::cmp_default_heuristics` method is used to determine the most suitable, supported stream format to use as the default. The `enumerate.rs` and `record_wav.rs` examples now work successfully on my linux machine. * Implement input stream support for wasapi backend This implements the following for the wasapi backend: - Device::supported_input_formats - Device::default_input_format - Device::default_output_format - EventLoop::build_input_stream Note that wasapi does not enumerate supported input/output stream formats for its devices. Instead, we query the `IsFormatSupported` method for supported formats ourselves. * Fix some warnings in the alsa backend * Update CHANGELOG for introduction of input streams and related items * Update README to show latest features supported by CPAL * Simplify beep example using Device::default_output_format * Remove old commented code from wasapi/stream.rs
2018-02-12 13:10:24 +00:00
//! 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 cpal;
extern crate hound;
fn main() {
// Setup the default input device and stream with the default input format.
let device = cpal::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 = cpal::EventLoop::new();
let stream_id = event_loop.build_input_stream(&device, &format)
.expect("Failed to build input stream");
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).unwrap();
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 |_, data| {
// 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().unwrap();
println!("Recording {} complete!", PATH);
}
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),
}
}