Limited shm frame count (#12346)

* Only keep 2x detect fps frames in SHM

* Don't delete previous shm frames in output

* Catch case where images do not exist

* Ensure files are closed

* Clear out all frames when shutting down

* Correct the number of frames saved

* Simplify empty shm error handling

* Improve frame safety

frigate/object_processing.py

@@ -659,6 +659,7 @@ def on(self, event_type: str, callback: Callable[[dict], None]):
     def update(self, frame_time, current_detections, motion_boxes, regions):
         # get the new frame
         frame_id = f"{self.name}{frame_time}"
+
         current_frame = self.frame_manager.get(
             frame_id, self.camera_config.frame_shape_yuv
         )
@@ -693,7 +694,7 @@ def update(self, frame_time, current_detections, motion_boxes, regions):
                 for c in self.callbacks["autotrack"]:
                     c(self.name, updated_obj, frame_time)
 
-            if thumb_update:
+            if thumb_update and current_frame is not None:
                 # ensure this frame is stored in the cache
                 if (
                     updated_obj.thumbnail_data["frame_time"] == frame_time
@@ -850,12 +851,16 @@ def update(self, frame_time, current_detections, motion_boxes, regions):
 
         with self.current_frame_lock:
             self.tracked_objects = tracked_objects
-            self.current_frame_time = frame_time
             self.motion_boxes = motion_boxes
             self.regions = regions
-            self._current_frame = current_frame
-            if self.previous_frame_id is not None:
-                self.frame_manager.close(self.previous_frame_id)
+
+            if current_frame is not None:
+                self.current_frame_time = frame_time
+                self._current_frame = current_frame
+
+                if self.previous_frame_id is not None:
+                    self.frame_manager.close(self.previous_frame_id)
+
             self.previous_frame_id = frame_id
 
 

frigate/output/output.py

@@ -45,7 +45,6 @@ def receiveSignal(signalNumber, frame):
     signal.signal(signal.SIGINT, receiveSignal)
 
     frame_manager = SharedMemoryFrameManager()
-    previous_frames = {}
 
     # start a websocket server on 8082
     WebSocketWSGIHandler.http_version = "1.1"
@@ -97,6 +96,9 @@ def receiveSignal(signalNumber, frame):
 
         frame = frame_manager.get(frame_id, config.cameras[camera].frame_shape_yuv)
 
+        if frame is None:
+            continue
+
         # send camera frame to ffmpeg process if websockets are connected
         if any(
             ws.environ["PATH_INFO"].endswith(camera) for ws in websocket_server.manager
@@ -124,12 +126,7 @@ def receiveSignal(signalNumber, frame):
         preview_recorders[camera].write_data(
             current_tracked_objects, motion_boxes, frame_time, frame
         )
-
-        # delete frames after they have been used for output
-        if camera in previous_frames:
-            frame_manager.delete(f"{camera}{previous_frames[camera]}")
-
-        previous_frames[camera] = frame_time
+        frame_manager.close(frame_id)
 
     move_preview_frames("clips")
 
@@ -149,7 +146,7 @@ def receiveSignal(signalNumber, frame):
 
         frame_id = f"{camera}{frame_time}"
         frame = frame_manager.get(frame_id, config.cameras[camera].frame_shape_yuv)
-        frame_manager.delete(frame_id)
+        frame_manager.close(frame_id)
 
     detection_subscriber.stop()
 

frigate/util/image.py

@@ -687,27 +687,31 @@ def delete(self, name):
 
 class SharedMemoryFrameManager(FrameManager):
     def __init__(self):
-        self.shm_store = {}
+        self.shm_store: dict[str, shared_memory.SharedMemory] = {}
 
-    def create(self, name, size) -> AnyStr:
+    def create(self, name: str, size) -> AnyStr:
         shm = shared_memory.SharedMemory(name=name, create=True, size=size)
         self.shm_store[name] = shm
         return shm.buf
 
-    def get(self, name, shape):
-        if name in self.shm_store:
-            shm = self.shm_store[name]
-        else:
-            shm = shared_memory.SharedMemory(name=name)
-            self.shm_store[name] = shm
-        return np.ndarray(shape, dtype=np.uint8, buffer=shm.buf)
+    def get(self, name: str, shape) -> Optional[np.ndarray]:
+        try:
+            if name in self.shm_store:
+                shm = self.shm_store[name]
+            else:
+                shm = shared_memory.SharedMemory(name=name)
+                self.shm_store[name] = shm
+            return np.ndarray(shape, dtype=np.uint8, buffer=shm.buf)
+        except FileNotFoundError:
+            logger.error(f"Failed to get {name} from SHM")
+            return None
 
-    def close(self, name):
+    def close(self, name: str):
         if name in self.shm_store:
             self.shm_store[name].close()
             del self.shm_store[name]
 
-    def delete(self, name):
+    def delete(self, name: str):
         if name in self.shm_store:
             self.shm_store[name].close()
             self.shm_store[name].unlink()

frigate/video.py

@@ -94,7 +94,7 @@ def start_or_restart_ffmpeg(
 
 def capture_frames(
     ffmpeg_process,
-    camera_name,
+    config: CameraConfig,
     frame_shape,
     frame_manager: FrameManager,
     frame_queue,
@@ -108,24 +108,36 @@ def capture_frames(
     frame_rate.start()
     skipped_eps = EventsPerSecond()
     skipped_eps.start()
+
+    shm_count = max(10, config.detect.fps * 2)
+    shm_frames: list[str] = []
+
     while True:
         fps.value = frame_rate.eps()
         skipped_fps.value = skipped_eps.eps()
-
         current_frame.value = datetime.datetime.now().timestamp()
-        frame_name = f"{camera_name}{current_frame.value}"
+        frame_name = f"{config.name}{current_frame.value}"
         frame_buffer = frame_manager.create(frame_name, frame_size)
         try:
             frame_buffer[:] = ffmpeg_process.stdout.read(frame_size)
+
+            # update frame cache and cleanup existing frames
+            shm_frames.append(frame_name)
+
+            if len(shm_frames) > shm_count:
+                expired_frame_name = shm_frames.pop(0)
+                frame_manager.delete(expired_frame_name)
         except Exception:
+            frame_manager.delete(frame_name)
+
             # shutdown has been initiated
             if stop_event.is_set():
                 break
-            logger.error(f"{camera_name}: Unable to read frames from ffmpeg process.")
+            logger.error(f"{config.name}: Unable to read frames from ffmpeg process.")
 
             if ffmpeg_process.poll() is not None:
                 logger.error(
-                    f"{camera_name}: ffmpeg process is not running. exiting capture thread..."
+                    f"{config.name}: ffmpeg process is not running. exiting capture thread..."
                 )
                 frame_manager.delete(frame_name)
                 break
@@ -137,12 +149,13 @@ def capture_frames(
         try:
             # add to the queue
             frame_queue.put(current_frame.value, False)
-            # close the frame
-            frame_manager.close(frame_name)
         except queue.Full:
             # if the queue is full, skip this frame
             skipped_eps.update()
-            frame_manager.delete(frame_name)
+
+    # clear out frames
+    for frame in shm_frames:
+        frame_manager.delete(frame)
 
 
 class CameraWatchdog(threading.Thread):
@@ -282,7 +295,7 @@ def start_ffmpeg_detect(self):
         )
         self.ffmpeg_pid.value = self.ffmpeg_detect_process.pid
         self.capture_thread = CameraCapture(
-            self.camera_name,
+            self.config,
             self.ffmpeg_detect_process,
             self.frame_shape,
             self.frame_queue,
@@ -321,7 +334,7 @@ def get_latest_segment_datetime(self, latest_segment: datetime.datetime) -> int:
 class CameraCapture(threading.Thread):
     def __init__(
         self,
-        camera_name,
+        config: CameraConfig,
         ffmpeg_process,
         frame_shape,
         frame_queue,
@@ -330,8 +343,8 @@ def __init__(
         stop_event,
     ):
         threading.Thread.__init__(self)
-        self.name = f"capture:{camera_name}"
-        self.camera_name = camera_name
+        self.name = f"capture:{config.name}"
+        self.config = config
         self.frame_shape = frame_shape
         self.frame_queue = frame_queue
         self.fps = fps
@@ -345,7 +358,7 @@ def __init__(
     def run(self):
         capture_frames(
             self.ffmpeg_process,
-            self.camera_name,
+            self.config,
             self.frame_shape,
             self.frame_manager,
             self.frame_queue,