ui: match C3XL display rate and gate stream encoding

launch_env.sh

@@ -15,6 +15,9 @@ export VECLIB_MAXIMUM_THREADS=1
 # headroom for this until ui is moved to the CPU.
 export QCOM_PRIORITY=12
 
+# C3XL panel runs at ~31.6Hz; targeting 60 causes constant false FPS warnings.
+export FPS=30
+
 if [ -z "$AGNOS_VERSION" ]; then
   export AGNOS_VERSION="19.7-c3xl-dev"
 fi
@@ -24,8 +27,9 @@ export STAGING_ROOT="/data/safe_staging"
 # Comma4-UI-Streamer (MJPEG UI stream) - set STREAM=0 to disable
 export STREAM=1
 export STREAM_PORT=8082
-export STREAM_QUALITY=50
-export STREAM_FPS=10
+export STREAM_QUALITY=40
+export STREAM_FPS=5
+export STREAM_MAX_WIDTH=540
 
 # --- system time (this hardware has no battery-backed RTC) ---
 # On a cold boot there is no sane clock: AGNOS restores a stale timestamp (or the epoch),

openpilot/system/ui/lib/ui_stream.py

@@ -24,16 +24,35 @@ class StreamState:
         self.frame = b""
         self.lock = threading.Lock()
         self.event = threading.Event()
+        self.clients = 0
+        self.snapshot_pending = False
 
     def update(self, jpeg):
         with self.lock:
             self.frame = jpeg
+            self.snapshot_pending = False
         self.event.set()
 
     def get(self):
         with self.lock:
             return self.frame
 
+    def client_enter(self):
+        with self.lock:
+            self.clients += 1
+
+    def client_exit(self):
+        with self.lock:
+            self.clients = max(0, self.clients - 1)
+
+    def request_snapshot(self):
+        with self.lock:
+            self.snapshot_pending = True
+
+    def has_demand(self):
+        with self.lock:
+            return self.clients > 0 or self.snapshot_pending
+
     def wait(self, t=2.0):
         self.event.wait(t)
         self.event.clear()
@@ -237,6 +256,7 @@ class StreamHandler(BaseHTTPRequestHandler):
             self.send_header("Cache-Control", "no-cache")
             self.send_header("Access-Control-Allow-Origin", "*")
             self.end_headers()
+            self.server._state.client_enter()
             try:
                 while True:
                     self.server._state.wait(2.0)
@@ -247,7 +267,11 @@ class StreamHandler(BaseHTTPRequestHandler):
                         self.wfile.write(b"\r\n")
             except (BrokenPipeError, ConnectionResetError):
                 pass
+            finally:
+                self.server._state.client_exit()
         elif self.path == "/snapshot":
+            self.server._state.request_snapshot()
+            self.server._state.wait(1.0)
             f = self.server._state.get()
             if f:
                 self.send_response(200)
@@ -423,6 +447,9 @@ def _encode_worker():
     raw, w, h, quality = item
     try:
       img = Image.frombytes("RGBA", (w, h), raw).transpose(Image.FLIP_TOP_BOTTOM).convert("RGB")
+      max_width = int(os.getenv("STREAM_MAX_WIDTH", "540"))
+      if img.width > max_width:
+        img.thumbnail((max_width, max_width * img.height // img.width), Image.Resampling.BILINEAR)
       buf = io.BytesIO()
       img.save(buf, "JPEG", quality=quality)
       if _state is not None:
@@ -503,7 +530,7 @@ def capture_frame(app, quality=50, target_fps=10):
     _app = app
   """Call from the render loop: snapshot texture, queue raw for async JPEG encode."""
   global _counter
-  if _state is None or app._render_texture is None:
+  if _state is None or app._render_texture is None or not _state.has_demand():
     return
   _counter += 1
   skip = max(1, int(getattr(app, "_target_fps", 60)) // max(1, int(target_fps)))