rvsttd: fade-out on last audio chunk fed to Moonshine, debug WAV stays raw

rvsttd/src/main.rs

@@ -113,17 +113,7 @@ impl DebugRecorder {
         self.audio.extend_from_slice(samples);
     }
 
-    fn save(mut self) {
-        // Apply 5ms fade-out to the end to avoid click at the trailing edge
-        let fade_samples = (SAMPLE_RATE as usize * 5) / 1000; // 5ms
-        if self.audio.len() > fade_samples {
-            let start = self.audio.len() - fade_samples;
-            for i in 0..fade_samples {
-                let t = 1.0 - (i as f32 / fade_samples as f32);
-                self.audio[start + i] *= t;
-            }
-        }
-
+    fn save(self) {
         // Write log
         let log_path = self.dir.join("session.log");
         match std::fs::File::create(&log_path) {
@@ -335,13 +325,44 @@ fn transcriber_loop(
     // Fixed 100ms window — cpal delivers every ~50ms (800 samples @ 16kHz),
     // so this captures 1-2 more callbacks worth of trailing audio.
     let drain_deadline = std::time::Instant::now() + Duration::from_millis(100);
+    let mut last_chunk: Option<Vec<f32>> = None;
     while std::time::Instant::now() < drain_deadline {
         match rx.recv_timeout(drain_deadline - std::time::Instant::now()) {
             Ok(chunk) => {
+                // Record raw audio for debug WAV
                 if let Some(ref mut r) = recorder {
                     r.add_audio(&chunk);
                 }
 
+                // Feed previous chunk to Moonshine, hold the latest for fade
+                if let Some(prev) = last_chunk.take() {
+                    unsafe {
+                        moonshine_transcribe_add_audio_to_stream(
+                            handle, stream_handle,
+                            prev.as_ptr(), prev.len() as u64,
+                            SAMPLE_RATE, 0,
+                        );
+                    }
+                }
+                last_chunk = Some(chunk);
+            }
+            Err(mpsc::RecvTimeoutError::Timeout) => break,
+            Err(mpsc::RecvTimeoutError::Disconnected) => break,
+        }
+    }
+
+    // Apply 5ms fade-out to the last chunk before feeding to Moonshine.
+    // The recorder already captured the unmodified audio for the debug WAV.
+    if let Some(mut chunk) = last_chunk.take() {
+        let fade_samples = (SAMPLE_RATE as usize * 5) / 1000;
+        if chunk.len() > fade_samples {
+            let start = chunk.len() - fade_samples;
+            for i in 0..fade_samples {
+                let t = 1.0 - (i as f32 / fade_samples as f32);
+                chunk[start + i] *= t;
+            }
+        }
+
         unsafe {
             moonshine_transcribe_add_audio_to_stream(
                 handle, stream_handle,
@@ -350,10 +371,6 @@ fn transcriber_loop(
             );
         }
     }
-            Err(mpsc::RecvTimeoutError::Timeout) => break,
-            Err(mpsc::RecvTimeoutError::Disconnected) => break,
-        }
-    }
 
     // If aborted (new session took over), skip final flush entirely
     if aborted.load(Ordering::SeqCst) {