make max target box a function of zoom factor

frigate/camera/state.py

@@ -16,7 +16,7 @@ from frigate.config import (
     ZoomingModeEnum,
 )
 from frigate.const import CLIPS_DIR, THUMB_DIR
-from frigate.ptz.autotrack import PtzAutoTracker
+from frigate.ptz.autotrack import PtzAutoTracker, calculate_max_target_box
 from frigate.track.tracked_object import TrackedObject
 from frigate.util.image import (
     SharedMemoryFrameManager,
@@ -134,8 +134,8 @@ class CameraState:
                         and self.camera_config.detect.width is not None
                         and self.camera_config.detect.height is not None
                     ):
-                        max_target_box = self.ptz_autotracker_thread.max_target_box(
-                            self.name
+                        max_target_box = calculate_max_target_box(
+                            self.camera_config.onvif.autotracking.zoom_factor
                         )
                         side_length = max_target_box * (
                             max(

frigate/ptz/autotrack.py

@@ -43,6 +43,11 @@ from frigate.util.image import SharedMemoryFrameManager, intersection_over_union
 logger = logging.getLogger(__name__)
 
 
+def calculate_max_target_box(zoom_factor: float) -> float:
+    """Return the largest target box ratio allowed for a zoom factor."""
+    return AUTOTRACKING_MAX_AREA_RATIO ** (1 / zoom_factor)
+
+
 def ptz_moving_at_frame_time(frame_time, ptz_start_time, ptz_stop_time):
     # Determine if the PTZ was in motion at the set frame time
     # for non ptz/autotracking cameras, this will always return False
@@ -332,11 +337,6 @@ class PtzAutoTracker(threading.Thread):
     def _reset_tracked_object_metrics(self, camera: str) -> None:
         self.tracked_object_metrics[camera] = {}
 
-    def max_target_box(self, camera: str) -> float:
-        """Return the largest target box ratio allowed for the zoom factor."""
-        zoom_factor = self.config.cameras[camera].onvif.autotracking.zoom_factor
-        return AUTOTRACKING_MAX_AREA_RATIO ** (1 / zoom_factor)
-
     async def _wait_until_stopped(
         self, camera: str, metrics: PTZMetrics | None = None
     ) -> None:
@@ -945,7 +945,7 @@ class PtzAutoTracker(threading.Thread):
         camera_config = self.config.cameras[camera]
         tom = self.tracked_object_metrics[camera]
         zoom_factor = camera_config.onvif.autotracking.zoom_factor
-        max_target_box = self.max_target_box(camera)
+        max_target_box = calculate_max_target_box(zoom_factor)
         camera_width = camera_config.frame_shape[1]
         camera_height = camera_config.frame_shape[0]
         camera_fps = camera_config.detect.fps
@@ -1179,7 +1179,7 @@ class PtzAutoTracker(threading.Thread):
         camera_config = self.config.cameras[camera]
         tom = self.tracked_object_metrics[camera]
         zoom_factor = camera_config.onvif.autotracking.zoom_factor
-        max_target_box = self.max_target_box(camera)
+        max_target_box = calculate_max_target_box(zoom_factor)
 
         # frame width and height
         camera_width = camera_config.frame_shape[1]

frigate/test/test_ptz_autotrack.py

@@ -17,7 +17,7 @@ from unittest.mock import MagicMock
 from frigate.camera import PTZMetrics
 from frigate.config import FrigateConfig
 from frigate.config.camera.updater import CameraConfigUpdateEnum
-from frigate.ptz.autotrack import PtzAutoTracker
+from frigate.ptz.autotrack import PtzAutoTracker, calculate_max_target_box
 
 CAMERA = "ptz_cam"
 
@@ -123,18 +123,10 @@ class TestAutotrackerDisable(unittest.TestCase):
         self.assertIs(payload, autotracking)
 
 
-class TestAutotrackerMaxTargetBox(unittest.TestCase):
-    def test_follows_live_zoom_factor(self) -> None:
-        # the debug overlay and the zoom decisions both read this, so it has to
-        # track a zoom_factor changed while an object is being followed
-        tracker = _make_tracker()
-        autotracking = tracker.config.cameras[CAMERA].onvif.autotracking
-
-        autotracking.zoom_factor = 0.5
-        self.assertAlmostEqual(tracker.max_target_box(CAMERA), 0.6**2)
-
-        autotracking.zoom_factor = 0.25
-        self.assertAlmostEqual(tracker.max_target_box(CAMERA), 0.6**4)
+class TestMaxTargetBox(unittest.TestCase):
+    def test_follows_zoom_factor(self) -> None:
+        self.assertAlmostEqual(calculate_max_target_box(0.5), 0.6**2)
+        self.assertAlmostEqual(calculate_max_target_box(0.25), 0.6**4)
 
 
 if __name__ == "__main__":