Support for baseband output to a soundcard

[m17rt] / m17app / src / soundmodem.rs

diff --git a/m17app/src/soundmodem.rs b/m17app/src/soundmodem.rs
index 9c05adad525f7885f7f21c99ae1077aa2bed64b7..74c176bba754a087cda4826f80c5348ced43e63e 100644 (file)
--- a/m17app/src/soundmodem.rs
+++ b/m17app/src/soundmodem.rs
@@ -547,3 +547,93 @@ impl OutputSink for NullOutputSink {
         let _ = self.end_tx.lock().unwrap().take();
     }
 }
         let _ = self.end_tx.lock().unwrap().take();
     }
 }

+
+pub struct OutputSoundcard {
+    // TODO: allow for inversion both here and in output
+    cpal_name: Option<String>,
+    end_tx: Mutex<Option<Sender<()>>>,
+}
+
+impl OutputSoundcard {
+    pub fn new() -> Self {
+        Self {
+            cpal_name: None,
+            end_tx: Mutex::new(None),
+        }
+    }
+
+    pub fn new_with_card(card_name: String) -> Self {
+        Self {
+            cpal_name: Some(card_name),
+            end_tx: Mutex::new(None),
+        }
+    }
+}
+
+impl OutputSink for OutputSoundcard {
+    fn start(&self, event_tx: SyncSender<SoundmodemEvent>, buffer: Arc<RwLock<OutputBuffer>>) {
+        let (end_tx, end_rx) = channel();
+        let cpal_name = self.cpal_name.clone();
+        std::thread::spawn(move || {
+            let host = cpal::default_host();
+            let device = if let Some(name) = cpal_name.as_deref() {
+                host.output_devices()
+                    .unwrap()
+                    .find(|d| d.name().unwrap() == name)
+                    .unwrap()
+            } else {
+                host.default_output_device().unwrap()
+            };
+            let mut configs = device.supported_output_configs().unwrap();
+            // TODO: more error handling
+            let config = configs
+                .find(|c| c.channels() == 1 && c.sample_format() == SampleFormat::I16)
+                .unwrap()
+                .with_sample_rate(SampleRate(48000));
+            let stream = device
+                .build_output_stream(
+                    &config.into(),
+                    move |data: &mut [i16], info: &cpal::OutputCallbackInfo| {
+                        let mut taken = 0;
+                        let ts = info.timestamp();
+                        let latency = ts
+                            .playback
+                            .duration_since(&ts.callback)
+                            .unwrap_or(Duration::ZERO);
+                        let mut buffer = buffer.write().unwrap();
+                        buffer.latency = latency;
+                        for out in data.iter_mut() {
+                            if let Some(s) = buffer.samples.pop_front() {
+                                *out = s;
+                                taken += 1;
+                            } else if buffer.idling {
+                                *out = 0;
+                            } else {
+                                debug!("output soundcard had underrun");
+                                let _ = event_tx.send(SoundmodemEvent::OutputUnderrun);
+                                break;
+                            }
+                        }
+                        //debug!("latency is {} ms, taken {taken}", latency.as_millis());
+                        let _ = event_tx.send(SoundmodemEvent::DidReadFromOutputBuffer {
+                            len: taken,
+                            timestamp: Instant::now(),
+                        });
+                    },
+                    |e| {
+                        // TODO: abort?
+                        debug!("error occurred in soundcard output: {e:?}");
+                    },
+                    None,
+                )
+                .unwrap();
+            stream.play().unwrap();
+            let _ = end_rx.recv();
+        });
+        *self.end_tx.lock().unwrap() = Some(end_tx);
+    }
+
+    fn close(&self) {
+        let _ = self.end_tx.lock().unwrap().take();
+    }
+}