GUI, lists PA devices, backend can watch audio stream

1 files changed, 74 insertions, 0 deletions

diff --git a/src/audio.rs b/src/audio.rs
new file mode 100644
index 0000000..526a227
--- /dev/null
+++ b/src/audio.rs
@@ -0,0 +1,74 @@
+extern crate portaudio;
+use portaudio as pa;
+
+const SAMPLE_RATE: f64 = 44100.0;
+const FRAMES: usize = 512;
+
+pub fn get_device_list() -> Result<Vec<(u32, String)>, pa::Error> {
+    let pa = try!(pa::PortAudio::new());
+    let default_host = try!(pa.default_host_api());
+    println!("Using default host: {:#?}", default_host);
+
+    let mut list = Vec::new();
+    let devices = try!(pa.devices());
+    for device in devices {
+        let (pa::DeviceIndex(idx), info) = try!(device);
+        if info.max_input_channels == 0 {
+            continue;
+        }
+        list.push((idx, info.name.to_string()));
+    }
+    Ok(list)
+}
+
+pub fn run(device_index: u32) -> Result<(), pa::Error> {
+    let pa = try!(pa::PortAudio::new());
+
+    let input_info = try!(pa.device_info(pa::DeviceIndex(device_index)));
+    println!("Using {} for input", input_info.name);
+
+    // Construct the input stream parameters.
+    let latency = input_info.default_low_input_latency;
+    let input_params = pa::StreamParameters::<f32>::new(pa::DeviceIndex(device_index), 1, true, latency);
+
+    // Check that the stream format is supported.
+    try!(pa.is_input_format_supported(input_params, SAMPLE_RATE));
+
+    // Construct the settings with which we'll open our duplex stream.
+    let settings = pa::InputStreamSettings::new(input_params, SAMPLE_RATE, FRAMES as u32);
+
+    // We'll use this channel to send the count_down to the main thread for fun.
+    let (sender, receiver) = ::std::sync::mpsc::channel();
+
+    // A callback to pass to the non-blocking stream.
+    let callback = move |pa::InputStreamCallbackArgs { buffer, .. }| {
+        sender.send(buffer.iter().map(|x| *x as f64).collect()).ok();
+        pa::Continue
+    };
+
+    // Construct a stream with input and output sample types of f32.
+    let mut stream = try!(pa.open_non_blocking_stream(settings, callback));
+
+    try!(stream.start());
+
+    let mut samples_index = 0;
+    // Do some stuff!
+    while let Ok(samples) = receiver.recv() {
+        samples_index += 1;
+        if samples_index % 100 != 0 {
+            continue;
+        }
+
+        let frequency_domain = ::transforms::fft(samples, SAMPLE_RATE);
+            
+        let max_frequency = frequency_domain.iter()
+            .fold(None as Option<::transforms::FrequencyBucket>, |max, next|
+                  if max.is_none() || max.clone().unwrap().intensity < next.intensity { Some(next.clone()) } else { max }
+            ).unwrap().max_freq;
+        println!("{}Hz", max_frequency.floor());
+    }
+
+    try!(stream.stop());
+
+    Ok(())
+}