diff --git a/app/main.py b/app/main.py
index a74855e..05f5397 100644
--- a/app/main.py
+++ b/app/main.py
@@ -283,13 +283,16 @@ async def ws_transcribe(ws: WebSocket):
                   f"({len(seg.pcm) / 2 / SAMPLE_RATE:.1f}s d'audio, niveau crête {peak}"
                   f"{', amplifié' if pcm is not seg.pcm else ''}), transcription...", flush=True)
 
-            # Diarisation (~30-80 ms CPU, dans un thread pour ne pas bloquer)
+            # Diarisation (~30-80 ms CPU). Strictement isolée : ni un blocage
+            # ni une erreur ne doivent empêcher la transcription qui suit.
             speaker = ""
             if diarizer is not None:
                 try:
-                    speaker = await asyncio.to_thread(diarizer.identify, pcm)
+                    speaker = await asyncio.wait_for(
+                        asyncio.to_thread(diarizer.identify, pcm), timeout=5.0
+                    )
                 except Exception as exc:
-                    print(f"[réunion {meeting_id}] diarisation échouée : {exc}", flush=True)
+                    print(f"[réunion {meeting_id}] diarisation ignorée : {exc}", flush=True)
 
             try:
                 text = await transcribe(pcm)
diff --git a/app/segmenter.py b/app/segmenter.py
index f52be69..e350279 100644
--- a/app/segmenter.py
+++ b/app/segmenter.py
@@ -48,14 +48,19 @@ class _AutoGain:
         self.gain = 1.0
 
     def process(self, frame: bytes) -> bytes:
-        peak = audioop.max(frame, 2)
-        if peak >= AGC_NOISE_FLOOR:
-            desired = min(AGC_MAX_GAIN, AGC_TARGET_PEAK / peak)
-            rate = AGC_ATTACK if desired > self.gain else AGC_RELEASE
-            self.gain += (desired - self.gain) * rate
-            self.gain = max(1.0, min(AGC_MAX_GAIN, self.gain))
-        if self.gain > 1.01:
-            return audioop.mul(frame, 2, self.gain)
+        # Toute erreur ici ne doit JAMAIS interrompre le découpage : on
+        # renvoie la trame d'origine en cas de souci.
+        try:
+            peak = audioop.max(frame, 2)
+            if peak >= AGC_NOISE_FLOOR:
+                desired = min(AGC_MAX_GAIN, AGC_TARGET_PEAK / peak)
+                rate = AGC_ATTACK if desired > self.gain else AGC_RELEASE
+                self.gain += (desired - self.gain) * rate
+                self.gain = max(1.0, min(AGC_MAX_GAIN, self.gain))
+            if self.gain > 1.01:
+                return audioop.mul(frame, 2, self.gain)  # audioop sature, ne déborde pas
+        except Exception:
+            return frame
         return frame