Autotracking improvements and fixes (#24633)

* 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.

* don't rebuild trackers for track list edits while autotracking is disabled

frigate/test/test_norfair_tracker_modes.py

@@ -0,0 +1,146 @@
+"""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_track_list_edit_while_disabled_keeps_objects(self):
+        tracker = self.make_tracker(enabled=False)
+        self.run_frames(tracker, 10)
+        ids = set(tracker.tracked_objects)
+
+        self.apply_onvif_update(tracker, _config(enabled=False, track=["car"]))
+        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),
+        )