fix autotracking tracker selection and crop before histogram conversion

- Rebuild the norfair trackers when an onvif save changes autotracking enabled_in_config or the PTZ-tracked labels. The trackers were only built at startup, so disabling autotracking or removing person from its track list in the UI made get_tracker pick a tracker that didn't exist, and the KeyError killed the camera process until restart. Saves that leave the selection alone, and runtime MQTT toggles, don't touch tracking.
- get_tracker now returns the default tracker that match_and_update actually feeds. On autotracking cameras it returned the static default for labels without their own tracker, so register missed the norfair object and lost the pre-initialization score history, and deregister pruned the wrong tracker.
- get_histogram crops the box out of each I420 plane before converting to BGR instead of converting the whole frame. It runs per detection per frame on autotracking cameras and now costs about 0.2 ms at any resolution, down from 1 ms at 1080p and 5 ms at 4K.

frigate/test/test_get_histogram.py

@@ -0,0 +1,41 @@
+import unittest
+
+import cv2
+import numpy as np
+
+from frigate.util.image import get_histogram
+
+
+def reference_histogram(image, x_min, y_min, x_max, y_max):
+    bgr = cv2.cvtColor(image, cv2.COLOR_YUV2BGR_I420)[y_min:y_max, x_min:x_max]
+    hist = cv2.calcHist([bgr], [0, 1, 2], None, [8, 8, 8], [0, 256, 0, 256, 0, 256])
+    return cv2.normalize(hist, hist).flatten()
+
+
+class TestGetHistogram(unittest.TestCase):
+    def setUp(self):
+        rng = np.random.default_rng(0)
+        self.frame = rng.integers(0, 255, (720 * 3 // 2, 1280), np.uint8)
+
+    def test_matches_full_frame_conversion_on_even_box(self):
+        box = (100, 200, 400, 600)
+        np.testing.assert_array_equal(
+            get_histogram(self.frame, *box), reference_histogram(self.frame, *box)
+        )
+
+    def test_odd_box_widens_to_even_edges(self):
+        np.testing.assert_array_equal(
+            get_histogram(self.frame, 101, 201, 399, 599),
+            reference_histogram(self.frame, 100, 200, 400, 600),
+        )
+
+    def test_box_is_clamped_to_frame(self):
+        np.testing.assert_array_equal(
+            get_histogram(self.frame, -10, -10, 5000, 5000),
+            reference_histogram(self.frame, 0, 0, 1280, 720),
+        )
+
+    def test_empty_box_returns_zeros(self):
+        hist = get_histogram(self.frame, 50, 50, 50, 50)
+        self.assertEqual(hist.shape, (512,))
+        self.assertEqual(hist.sum(), 0)

frigate/test/test_norfair_tracker_modes.py

@@ -0,0 +1,136 @@
+"""Tracker selection when autotracking config changes at runtime."""
+
+import unittest
+from unittest.mock import MagicMock
+
+import numpy as np
+
+from frigate.camera import PTZMetrics
+from frigate.config import FrigateConfig
+from frigate.track.norfair_tracker import NorfairTracker
+
+CAMERA = "ptz_cam"
+BOX = (400, 200, 500, 500)
+
+
+def _config(enabled: bool, track: list[str] | None = None) -> FrigateConfig:
+    autotracking: dict = {"enabled": enabled, "required_zones": ["zone"]}
+
+    if track is not None:
+        autotracking["track"] = track
+
+    return FrigateConfig(
+        **{
+            "mqtt": {"enabled": False},
+            "cameras": {
+                CAMERA: {
+                    "ffmpeg": {
+                        "inputs": [
+                            {"path": "rtsp://10.0.0.1:554/video", "roles": ["detect"]}
+                        ]
+                    },
+                    "detect": {"width": 1280, "height": 720},
+                    "zones": {"zone": {"coordinates": "0,0,1,0,1,1,0,1"}},
+                    "onvif": {"host": "10.0.0.1", "autotracking": autotracking},
+                }
+            },
+        }
+    )
+
+
+class TestTrackerSelection(unittest.TestCase):
+    def setUp(self) -> None:
+        self.frame_time = 1000.0
+
+    def make_tracker(self, enabled: bool) -> NorfairTracker:
+        camera_config = _config(enabled).cameras[CAMERA]
+        tracker = NorfairTracker(camera_config, PTZMetrics())
+        tracker.frame_manager = MagicMock()
+        tracker.frame_manager.get.return_value = np.zeros(
+            camera_config.frame_shape_yuv, dtype=np.uint8
+        )
+        tracker.ptz_motion_estimator = MagicMock()
+        tracker.ptz_motion_estimator.motion_estimator.return_value = None
+        return tracker
+
+    def apply_onvif_update(self, tracker: NorfairTracker, config: FrigateConfig):
+        """Apply an onvif config update the way the camera process does."""
+        tracker.camera_config.onvif = config.cameras[CAMERA].onvif
+        tracker.sync_trackers()
+
+    def run_frames(self, tracker: NorfairTracker, count: int, label="person"):
+        for _ in range(count):
+            self.frame_time += 0.2
+            tracker.match_and_update(
+                "frame",
+                self.frame_time,
+                [(label, 0.9, BOX, 30000, 0.33, (0, 0, 640, 640))],
+            )
+
+    def test_disabling_autotracking_falls_back_to_static_tracker(self):
+        tracker = self.make_tracker(enabled=True)
+        self.run_frames(tracker, 10)
+        self.assertIs(tracker.get_tracker("person"), tracker.trackers["person"]["ptz"])
+
+        self.apply_onvif_update(tracker, _config(enabled=False))
+        self.run_frames(tracker, 10)
+
+        self.assertIs(tracker.get_tracker("person"), tracker.default_tracker["static"])
+        self.assertEqual(len(tracker.tracked_objects), 1)
+
+    def test_enabling_autotracking_uses_ptz_tracker(self):
+        tracker = self.make_tracker(enabled=False)
+        self.run_frames(tracker, 10)
+        self.assertIs(tracker.get_tracker("person"), tracker.default_tracker["static"])
+
+        self.apply_onvif_update(tracker, _config(enabled=True))
+        self.run_frames(tracker, 10)
+
+        self.assertIs(tracker.get_tracker("person"), tracker.trackers["person"]["ptz"])
+        self.assertEqual(len(tracker.tracked_objects), 1)
+
+    def test_removing_label_from_autotracking_keeps_tracking(self):
+        tracker = self.make_tracker(enabled=True)
+        self.run_frames(tracker, 10)
+
+        self.apply_onvif_update(tracker, _config(enabled=True, track=["car"]))
+        self.run_frames(tracker, 10)
+
+        self.assertNotIn("person", tracker.trackers)
+        self.assertIs(tracker.get_tracker("person"), tracker.default_tracker["ptz"])
+        self.assertEqual(len(tracker.tracked_objects), 1)
+
+    def test_unrelated_onvif_update_keeps_objects(self):
+        tracker = self.make_tracker(enabled=True)
+        self.run_frames(tracker, 10)
+        ids = set(tracker.tracked_objects)
+
+        config = _config(enabled=True)
+        config.cameras[CAMERA].onvif.password = "changed"
+        self.apply_onvif_update(tracker, config)
+        self.run_frames(tracker, 5)
+
+        self.assertEqual(set(tracker.tracked_objects), ids)
+
+    def test_runtime_toggle_keeps_objects(self):
+        # MQTT and the autotracker only flip enabled, never enabled_in_config
+        tracker = self.make_tracker(enabled=True)
+        self.run_frames(tracker, 10)
+        ids = set(tracker.tracked_objects)
+
+        tracker.camera_config.onvif.autotracking.enabled = False
+        tracker.sync_trackers()
+        self.run_frames(tracker, 5)
+
+        self.assertEqual(set(tracker.tracked_objects), ids)
+
+    def test_unlisted_label_uses_the_default_tracker_that_holds_it(self):
+        tracker = self.make_tracker(enabled=True)
+        self.run_frames(tracker, 10, label="dog")
+
+        default = tracker.get_tracker("dog")
+        self.assertIs(default, tracker.default_tracker["ptz"])
+        self.assertEqual(
+            {str(o.global_id) for o in default.tracked_objects},
+            set(tracker.track_id_map),
+        )

frigate/track/norfair_tracker.py

@@ -180,48 +180,9 @@ class NorfairTracker(ObjectTracker):
         }
 
         self.trackers: dict[str, dict[str, Tracker]] = {}
-        # Handle static trackers
-        for obj_type, tracker_config in self.object_type_configs.items():
-            if obj_type in self.camera_config.objects.track:
-                if obj_type not in self.trackers:
-                    self.trackers[obj_type] = {}
-                self.trackers[obj_type]["static"] = self._create_tracker(
-                    obj_type, tracker_config
-                )
-
-        # Handle PTZ trackers
-        for obj_type, tracker_config in self.ptz_object_type_configs.items():
-            if (
-                obj_type in self.camera_config.onvif.autotracking.track
-                and self.camera_config.onvif.autotracking.enabled_in_config
-            ):
-                if obj_type not in self.trackers:
-                    self.trackers[obj_type] = {}
-                self.trackers[obj_type]["ptz"] = self._create_tracker(
-                    obj_type, tracker_config
-                )
-
-        # Initialize default trackers
-        self.default_tracker = {
-            "static": Tracker(
-                distance_function=frigate_distance,
-                distance_threshold=self.default_tracker_config[  # type: ignore[arg-type]
-                    "distance_threshold"
-                ],
-                initialization_delay=self.detect_config.min_initialized,
-                hit_counter_max=self.detect_config.max_disappeared,  # type: ignore[arg-type]
-                filter_factory=self.default_tracker_config["filter_factory"],  # type: ignore[arg-type]
-            ),
-            "ptz": Tracker(
-                distance_function=frigate_distance,
-                distance_threshold=self.default_ptz_tracker_config[
-                    "distance_threshold"
-                ],  # type: ignore[arg-type]
-                initialization_delay=self.detect_config.min_initialized,
-                hit_counter_max=self.detect_config.max_disappeared,  # type: ignore[arg-type]
-                filter_factory=self.default_ptz_tracker_config["filter_factory"],  # type: ignore[arg-type]
-            ),
-        }
+        self.default_tracker: dict[str, Tracker] = {}
+        self.tracker_selection: tuple[bool | None, tuple[str, ...]] | None = None
+        self.sync_trackers()
 
         if self.camera_config.onvif.autotracking.enabled:
             self.ptz_motion_estimator = PtzMotionEstimator(
@@ -257,18 +218,86 @@ class NorfairTracker(ObjectTracker):
 
         return Tracker(**tracker_params)
 
-    def get_tracker(self, object_type: str) -> Tracker:
-        """Get the appropriate tracker based on object type and camera mode."""
-        mode = (
+    def _tracker_selection(self) -> tuple[bool | None, tuple[str, ...]]:
+        autotracking = self.camera_config.onvif.autotracking
+        ptz_labels = tuple(
+            label
+            for label in self.ptz_object_type_configs
+            if label in autotracking.track
+        )
+        return (autotracking.enabled_in_config, ptz_labels)
+
+    def sync_trackers(self) -> None:
+        """Rebuild the trackers when the config that selects them has changed.
+
+        The camera process receives onvif config updates at runtime, so which
+        labels use a PTZ tracker can change after startup. Rebuilding drops
+        norfair state, so an update that leaves the selection alone is a no-op.
+        """
+        selection = self._tracker_selection()
+
+        if selection == self.tracker_selection:
+            return
+
+        if self.tracker_selection is not None:
+            logger.debug(
+                "%s: autotracking changed, rebuilding trackers", self.camera_name
+            )
+
+        self.tracker_selection = selection
+        ptz_enabled, ptz_labels = selection
+        self.trackers = {}
+
+        for obj_type, tracker_config in self.object_type_configs.items():
+            if obj_type in self.camera_config.objects.track:
+                self.trackers.setdefault(obj_type, {})["static"] = self._create_tracker(
+                    obj_type, tracker_config
+                )
+
+        if ptz_enabled:
+            for obj_type, tracker_config in self.ptz_object_type_configs.items():
+                if obj_type in ptz_labels:
+                    self.trackers.setdefault(obj_type, {})["ptz"] = (
+                        self._create_tracker(obj_type, tracker_config)
+                    )
+
+        self.default_tracker = {
+            "static": Tracker(
+                distance_function=frigate_distance,
+                distance_threshold=self.default_tracker_config[  # type: ignore[arg-type]
+                    "distance_threshold"
+                ],
+                initialization_delay=self.detect_config.min_initialized,
+                hit_counter_max=self.detect_config.max_disappeared,  # type: ignore[arg-type]
+                filter_factory=self.default_tracker_config["filter_factory"],  # type: ignore[arg-type]
+            ),
+            "ptz": Tracker(
+                distance_function=frigate_distance,
+                distance_threshold=self.default_ptz_tracker_config[
+                    "distance_threshold"
+                ],  # type: ignore[arg-type]
+                initialization_delay=self.detect_config.min_initialized,
+                hit_counter_max=self.detect_config.max_disappeared,  # type: ignore[arg-type]
+                filter_factory=self.default_ptz_tracker_config["filter_factory"],  # type: ignore[arg-type]
+            ),
+        }
+
+    def default_mode(self) -> str:
+        return (
             "ptz"
             if self.camera_config.onvif.autotracking.enabled_in_config
-            and object_type in self.camera_config.onvif.autotracking.track
-            and object_type in self.ptz_object_type_configs.keys()
             else "static"
         )
-        if object_type in self.trackers:
-            return self.trackers[object_type][mode]
-        return self.default_tracker[mode]
+
+    def get_tracker(self, object_type: str) -> Tracker:
+        """Get the tracker that match_and_update feeds this label's detections to."""
+        trackers = self.trackers.get(object_type)
+
+        if trackers is None:
+            return self.default_tracker[self.default_mode()]
+
+        # sync_trackers only creates a ptz tracker for labels the config selects
+        return trackers["ptz"] if "ptz" in trackers else trackers["static"]
 
     def register(self, track_id: str, obj: dict[str, Any]) -> None:
         rand_id = "".join(random.choices(string.ascii_lowercase + string.digits, k=6))
@@ -534,7 +563,7 @@ class NorfairTracker(ObjectTracker):
             points = np.array([[obj[2][0], obj[2][1]], [obj[2][2], obj[2][3]]])
 
             embedding = None
-            if self.camera_config.onvif.autotracking.enabled:
+            if self.camera_config.onvif.autotracking.enabled and yuv_frame is not None:
                 embedding = get_histogram(
                     yuv_frame, obj[2][0], obj[2][1], obj[2][2], obj[2][3]
                 )
@@ -587,12 +616,7 @@ class NorfairTracker(ObjectTracker):
                 default_detections.extend(dets)
 
         # Update default tracker with untracked detections
-        mode = (
-            "ptz"
-            if self.camera_config.onvif.autotracking.enabled_in_config
-            else "static"
-        )
-        tracked_objects = self.default_tracker[mode].update(
+        tracked_objects = self.default_tracker[self.default_mode()].update(
             detections=default_detections, coord_transformations=coord_transformations
         )
         all_tracked_objects.extend(tracked_objects)

frigate/util/image.py

@@ -1241,9 +1241,42 @@ def get_image_from_recording(
     return image_data
 
 
-def get_histogram(image, x_min, y_min, x_max, y_max):
-    image_bgr = cv2.cvtColor(image, cv2.COLOR_YUV2BGR_I420)
-    image_bgr = image_bgr[y_min:y_max, x_min:x_max]
+def get_histogram(
+    image: np.ndarray, x_min: int, y_min: int, x_max: int, y_max: int
+) -> np.ndarray:
+    """Return a normalized 8x8x8 BGR histogram of a box in an I420 frame.
+
+    The box is cropped from each YUV plane before color conversion, so the
+    cost depends on the box size rather than the frame size. Box edges are
+    widened to even coordinates to keep chroma alignment.
+    """
+    height = image.shape[0] * 2 // 3
+    width = image.shape[1]
+    x_min = max(0, x_min // 2 * 2)
+    y_min = max(0, y_min // 2 * 2)
+    x_max = min(width, (x_max + 1) // 2 * 2)
+    y_max = min(height, (y_max + 1) // 2 * 2)
+
+    if x_max - x_min < 2 or y_max - y_min < 2:
+        return np.zeros(512, np.float32)
+
+    flat = image.reshape(-1)
+    y_size = height * width
+    uv_size = y_size // 4
+    y_plane = flat[:y_size].reshape(height, width)
+    u_plane = flat[y_size : y_size + uv_size].reshape(height // 2, width // 2)
+    v_plane = flat[y_size + uv_size : y_size + 2 * uv_size].reshape(
+        height // 2, width // 2
+    )
+
+    crop = np.concatenate(
+        (
+            y_plane[y_min:y_max, x_min:x_max].ravel(),
+            u_plane[y_min // 2 : y_max // 2, x_min // 2 : x_max // 2].ravel(),
+            v_plane[y_min // 2 : y_max // 2, x_min // 2 : x_max // 2].ravel(),
+        )
+    ).reshape((y_max - y_min) * 3 // 2, x_max - x_min)
+    image_bgr = cv2.cvtColor(crop, cv2.COLOR_YUV2BGR_I420)
 
     hist = cv2.calcHist(
         [image_bgr], [0, 1, 2], None, [8, 8, 8], [0, 256, 0, 256, 0, 256]

frigate/video/detect.py

@@ -302,6 +302,7 @@ def process_frames(
             motion_detector.autotracking_enabled = (
                 camera_config.onvif.autotracking.enabled
             )
+            object_tracker.sync_trackers()
 
         if (
             not camera_enabled