tts: add an audio output port, and feed TTS utterances into it

src/audio.rs

@@ -1,4 +1,4 @@
-use jack::{AudioIn, ClientOptions};
+use jack::{AudioIn, AudioOut, ClientOptions};
 use oximedia_metering::vu_meter::VuMeter;
 use tokio::sync::*;
 
@@ -32,15 +32,23 @@ pub struct MicStream {
     pub sample_rate: u32
 }
 
-pub async fn start_audio_input(messages: &mpsc::Sender<String>) -> (AudioInputControl, MicStream) {
+#[derive(Debug)]
+pub struct TtsOutStream {
+    pub sink: mpsc::Sender<Vec<f32>>,
+    pub sample_rate: u32
+}
+
+pub async fn start_audio_input(messages: &mpsc::Sender<String>) -> (AudioInputControl, MicStream, TtsOutStream) {
 
     let (exit_tx, exit_rx) = oneshot::channel();
 
     let (mic_audio_sink, mic_audio_src) = mpsc::channel(32);
+    let (tts_audio_sink, mut tts_audio_src) = mpsc::channel(32);
     let (volume_sink, volume_src) = watch::channel(0.);
 
     let (client, _status) = jack::Client::new("Eva-Cohost", ClientOptions::default() | ClientOptions::SESSION_ID).unwrap();
     let mic_port = client.register_port("microphone-in", AudioIn::default()).unwrap();
+    let mut tts_port = client.register_port("tts-out", AudioOut::default()).unwrap();
     let rate = client.sample_rate();
 
     if let Ok(_) = client.connect_ports_by_name("mixxx-mic-1:capture_MONO", mic_port.name().unwrap().as_str()) {
@@ -50,6 +58,8 @@ pub async fn start_audio_input(messages: &mpsc::Sender<String>) -> (AudioInputCo
     }
 
     let mut meter = VuMeter::new(rate.into(), 1, None);
+    let mut tts_output_buf = vec![];
+    tts_output_buf.reserve(1024);
 
     let handler = jack::contrib::ClosureProcessHandler::new(move |_client, scope| {
         if mic_port.connected_count().unwrap() > 0 {
@@ -67,6 +77,25 @@ pub async fn start_audio_input(messages: &mpsc::Sender<String>) -> (AudioInputCo
                 }
             });
         }
+
+
+        if let Ok(mut next_outbuf) = tts_audio_src.try_recv() {
+            tts_output_buf.append(&mut next_outbuf);
+        }   
+
+        if tts_port.connected_count().unwrap() > 0 && !tts_output_buf.is_empty() {
+            let outbuf = tts_port.as_mut_slice(scope);
+            let mut next_segment: Vec<f32> = tts_output_buf.drain(0..(outbuf.len()).min(tts_output_buf.len())).collect();
+            let underrun = outbuf.len() - next_segment.len();
+            if underrun > 0 {
+                for _ in 0..underrun {
+                    next_segment.push(0.);
+                }
+            }
+
+            outbuf.copy_from_slice(&next_segment);
+        }
+
         jack::Control::Continue
     });
 
@@ -84,5 +113,8 @@ pub async fn start_audio_input(messages: &mpsc::Sender<String>) -> (AudioInputCo
     }, MicStream {
         sample_rate: rate,
         src: mic_audio_src
+    }, TtsOutStream {
+        sample_rate: rate,
+        sink: tts_audio_sink
     })
 }