Stability: drop ServerQuery-only register call + cap viewer default

.env.example

@@ -52,15 +52,18 @@ TS6_CHANNEL_PASSWORD=
 # - STREAM_MODE: 1 = request-based (server forwards notifyjoinstreamrequest
 #   for each viewer and the bot replies via respondjoinstreamrequest);
 #   0 = auto-accept.
-# - STREAM_VIEWER_LIMIT: -1 = unlimited (TS3 convention). 0 is interpreted
-#   by some TS6 builds as "no viewers allowed", which silently drops every
-#   join attempt.
+# - STREAM_VIEWER_LIMIT: each viewer spins up its own VP8 encoder
+#   (~280 MB RSS at 720p30) so unlimited can OOM a small host. The default
+#   of 4 is conservative; bump it once you've measured memory under load.
+#   -1 = unlimited (TS3 convention). 0 is interpreted by some TS6 builds
+#   as "no viewers allowed", which silently drops every join attempt -
+#   don't use 0.
 # - STREAM_BITRATE: hint to the server (kbps); 4608 mirrors the default the
 #   TS6 client uses for "high quality" screen share.
 STREAM_BITRATE=4608
 STREAM_ACCESSIBILITY=0
 STREAM_MODE=1
-STREAM_VIEWER_LIMIT=-1
+STREAM_VIEWER_LIMIT=4
 
 # --- WebRTC ICE servers ----------------------------------------------------
 # STUN exposes the bot's public-NAT'd IP as a server-reflexive candidate;

src/ts6_stream_bot/config.py

@@ -108,8 +108,13 @@ class Settings(BaseSettings):
         ),
     )
     STREAM_VIEWER_LIMIT: int = Field(
-        default=-1,
-        description="Max viewers; -1 = unlimited (TS3 convention).",
+        default=4,
+        description=(
+            "Max concurrent viewers. Each viewer spins up its own VP8 encoder "
+            "(~280 MB RSS at 720p30); without a cap the bot can OOM the host "
+            "before the operator notices. -1 = unlimited (TS3 convention) - "
+            "only set this if you've measured memory under load."
+        ),
     )
 
     # --- WebRTC ICE -------------------------------------------------------

src/ts6_stream_bot/pipeline/controller.py

@@ -245,7 +245,6 @@ async def _allocate_stream(self) -> None:
             return
 
         signaling = StreamSignaling(self._ts3_client)
-        signaling.register_stream_notifications()
 
         capture_config = VideoCaptureConfig(
             display=settings.DISPLAY,

src/ts6_stream_bot/pipeline/stream_signaling.py

@@ -285,10 +285,13 @@ def _stream_from_params(p: dict[str, str], *, audio_key: str) -> ActiveStream:
 
     # --- outbound commands ------------------------------------------------
 
-    def register_stream_notifications(self) -> None:
-        """Subscribe to the server-side notifications we need. Idempotent."""
-        for event in ("channel", "server", "textchannel"):
-            self._client.send_command(build_command("servernotifyregister", {"event": event}))
+    # Note: voice clients (which is what we are) receive stream-related
+    # notifications automatically by virtue of being in the channel; the
+    # ``servernotifyregister`` command is for ServerQuery clients only and
+    # the TS6 server replies with ``error id=516 invalid client type`` if
+    # we send it. The ts6-manager port we started from registered three
+    # events here because it ran as a ServerQuery client - that doesn't
+    # apply to us.
 
     def send_setup_stream(
         self,

tests/test_stream_signaling.py

@@ -241,15 +241,6 @@ def test_send_stream_stop_and_remove_client() -> None:
     assert rm_cmd.params["clid"] == "42"
 
 
-def test_register_stream_notifications_subscribes_to_three_events() -> None:
-    client = _FakeClient()
-    sig = StreamSignaling(client)  # type: ignore[arg-type]
-    sig.register_stream_notifications()
-
-    events = [parse_command(c).params["event"] for c in client.sent]
-    assert events == ["channel", "server", "textchannel"]
-
-
 # --- chaining with prior on_command ---------------------------------------