Autotracking: reset motion estimator (#7129)

* reset motion estimator after returning to preset

* small tweaks and a bugfix

frigate/track/norfair_tracker.py

@@ -67,7 +67,9 @@ class NorfairTracker(ObjectTracker):
         self.max_disappeared = config.detect.max_disappeared
         self.camera_config = config
         self.detect_config = config.detect
+        self.ptz_metrics = ptz_metrics
         self.ptz_autotracker_enabled = ptz_metrics["ptz_autotracker_enabled"]
+        self.ptz_motion_estimator = {}
         self.camera_name = config.name
         self.track_id_map = {}
         # TODO: could also initialize a tracker per object class if there
@@ -79,7 +81,9 @@ class NorfairTracker(ObjectTracker):
             hit_counter_max=self.max_disappeared,
         )
         if self.ptz_autotracker_enabled.value:
-            self.ptz_motion_estimator = PtzMotionEstimator(config, ptz_metrics)
+            self.ptz_motion_estimator = PtzMotionEstimator(
+                self.camera_config, self.ptz_metrics
+            )
 
     def register(self, track_id, obj):
         rand_id = "".join(random.choices(string.ascii_lowercase + string.digits, k=6))
@@ -244,6 +248,12 @@ class NorfairTracker(ObjectTracker):
         coord_transformations = None
 
         if self.ptz_autotracker_enabled.value:
+            # we must have been enabled by mqtt, so set up the estimator
+            if not self.ptz_motion_estimator:
+                self.ptz_motion_estimator = PtzMotionEstimator(
+                    self.camera_config, self.ptz_metrics
+                )
+
             coord_transformations = self.ptz_motion_estimator.motion_estimator(
                 detections, frame_time, self.camera_name
             )