Move recording and Discord voice to PulseAudio

drb-edge-node/app/config.py

@@ -18,12 +18,27 @@ class Settings(BaseSettings):
     # C2 server (audio upload destination); None disables upload
     c2_url: Optional[str] = None
 
-    # Local Icecast
+    # Local Icecast — live listening only (frontend / mobile).
+    # NOT used for call recording or Discord voice: it lags 1s and drifts to 100s+.
     icecast_host: str = "localhost"
     icecast_port: int = 8000
     icecast_mount: str = "/radio"
     icecast_source_password: str = "hackme"
 
+    # PulseAudio — the low-latency path used for call recording and Discord voice.
+    # Liquidsoap (op25 container) writes into the `drb_sink` null sink; we capture
+    # its monitor. Addressed explicitly rather than via "default" because the op25
+    # entrypoint starts pulseaudio with -n and never applies system.pa's
+    # `set-default-source` line.
+    pulse_source: str = "drb_sink.monitor"
+    # Bounded wait for the shared PulseAudio socket before launching FFmpeg.
+    pulse_wait_timeout: float = 30.0
+
+    # Call segmentation — seconds with no active transmission before the current
+    # recording is closed out. Consecutive grants on the SAME talkgroup inside this
+    # window are kept in one recording so back-and-forth traffic stays together.
+    call_idle_timeout: float = 3.0
+
     # OP25 container
     op25_api_url: str = "http://localhost:8001"
     op25_terminal_url: str = "http://localhost:8081"