Auto-recover DXGI capture after duplication interface loss

BetterCam/DXcam engines now detect when the DXGI Desktop Duplication
interface is lost (display mode change, sleep/wake, UAC prompt, etc.)
and automatically reinitialize the camera with a 3-second cooldown
between attempts, instead of error-looping indefinitely.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/core/capture_engines/bettercam_engine.py

@@ -1,6 +1,7 @@
 """BetterCam-based screen capture engine (Windows only, DXGI Desktop Duplication)."""
 
 import sys
+import time
 from typing import Any, Dict, List, Optional
 
 import numpy as np
@@ -15,6 +16,8 @@ from wled_controller.utils import get_logger
 
 logger = get_logger(__name__)
 
+_REINIT_COOLDOWN = 3.0  # seconds between re-init attempts
+
 
 class BetterCamCaptureStream(CaptureStream):
     """BetterCam capture stream for a specific display."""
@@ -23,6 +26,7 @@ class BetterCamCaptureStream(CaptureStream):
         super().__init__(display_index, config)
         self._camera = None
         self._bettercam = None
+        self._last_reinit: float = 0
 
     def initialize(self) -> None:
         try:
@@ -48,6 +52,7 @@ class BetterCamCaptureStream(CaptureStream):
             raise RuntimeError(f"Failed to create BetterCam camera for display {self.display_index}")
 
         self._initialized = True
+        self._last_reinit = time.monotonic()
         logger.info(f"BetterCam capture stream initialized (display={self.display_index})")
 
     def cleanup(self) -> None:
@@ -72,6 +77,24 @@ class BetterCamCaptureStream(CaptureStream):
         self._initialized = False
         logger.info(f"BetterCam capture stream cleaned up (display={self.display_index})")
 
+    def _try_reinit(self) -> bool:
+        """Attempt to reinitialize the DXGI capture after a failure.
+
+        Returns True if reinit succeeded, False if on cooldown or failed.
+        """
+        now = time.monotonic()
+        if now - self._last_reinit < _REINIT_COOLDOWN:
+            return False
+        self._last_reinit = now
+        logger.warning(f"BetterCam: reinitializing camera for display {self.display_index}")
+        try:
+            self.cleanup()
+            self.initialize()
+            return True
+        except Exception as reinit_err:
+            logger.error(f"BetterCam reinit failed (display={self.display_index}): {reinit_err}")
+            return False
+
     def capture_frame(self) -> Optional[ScreenCapture]:
         if not self._initialized:
             self.initialize()
@@ -98,6 +121,10 @@ class BetterCamCaptureStream(CaptureStream):
             raise
         except Exception as e:
             logger.error(f"Failed to capture display {self.display_index} with BetterCam: {e}")
+            # DXGI duplication can be lost after display changes / sleep / UAC.
+            # Attempt to recreate the camera so capture can recover.
+            if self._try_reinit():
+                return None  # let the caller retry on next tick
             raise RuntimeError(f"Screen capture failed: {e}")
 
 

server/src/wled_controller/core/capture_engines/dxcam_engine.py

@@ -1,6 +1,7 @@
 """DXcam-based screen capture engine (Windows only, DXGI Desktop Duplication)."""
 
 import sys
+import time
 from typing import Any, Dict, List, Optional
 
 import numpy as np
@@ -15,6 +16,8 @@ from wled_controller.utils import get_logger
 
 logger = get_logger(__name__)
 
+_REINIT_COOLDOWN = 3.0  # seconds between re-init attempts
+
 
 class DXcamCaptureStream(CaptureStream):
     """DXcam capture stream for a specific display."""
@@ -23,6 +26,7 @@ class DXcamCaptureStream(CaptureStream):
         super().__init__(display_index, config)
         self._camera = None
         self._dxcam = None
+        self._last_reinit: float = 0
 
     def initialize(self) -> None:
         try:
@@ -48,6 +52,7 @@ class DXcamCaptureStream(CaptureStream):
             raise RuntimeError(f"Failed to create DXcam camera for display {self.display_index}")
 
         self._initialized = True
+        self._last_reinit = time.monotonic()
         logger.info(f"DXcam capture stream initialized (display={self.display_index})")
 
     def cleanup(self) -> None:
@@ -72,6 +77,24 @@ class DXcamCaptureStream(CaptureStream):
         self._initialized = False
         logger.info(f"DXcam capture stream cleaned up (display={self.display_index})")
 
+    def _try_reinit(self) -> bool:
+        """Attempt to reinitialize the DXGI capture after a failure.
+
+        Returns True if reinit succeeded, False if on cooldown or failed.
+        """
+        now = time.monotonic()
+        if now - self._last_reinit < _REINIT_COOLDOWN:
+            return False
+        self._last_reinit = now
+        logger.warning(f"DXcam: reinitializing camera for display {self.display_index}")
+        try:
+            self.cleanup()
+            self.initialize()
+            return True
+        except Exception as reinit_err:
+            logger.error(f"DXcam reinit failed (display={self.display_index}): {reinit_err}")
+            return False
+
     def capture_frame(self) -> Optional[ScreenCapture]:
         if not self._initialized:
             self.initialize()
@@ -98,6 +121,10 @@ class DXcamCaptureStream(CaptureStream):
             raise
         except Exception as e:
             logger.error(f"Failed to capture display {self.display_index} with DXcam: {e}")
+            # DXGI duplication can be lost after display changes / sleep / UAC.
+            # Attempt to recreate the camera so capture can recover.
+            if self._try_reinit():
+                return None  # let the caller retry on next tick
             raise RuntimeError(f"Screen capture failed: {e}")