Custom classes for Process and Metrics (#13950)

* Subclass Process for audio_process

* Introduce custom mp.Process subclass

In preparation to switch the multiprocessing startup method away from
"fork", we cannot rely on os.fork cloning the log state at fork time.
Instead, we have to set up logging before we run the business logic of
each process.

* Make camera_metrics into a class

* Make ptz_metrics into a class

* Fixed PtzMotionEstimator.ptz_metrics type annotation

* Removed pointless variables

* Do not start audio processor when no audio cameras are configured

frigate/comms/dispatcher.py

@@ -6,6 +6,7 @@ import logging
 from abc import ABC, abstractmethod
 from typing import Any, Callable, Optional
 
+from frigate.camera import PTZMetrics
 from frigate.comms.config_updater import ConfigPublisher
 from frigate.config import BirdseyeModeEnum, FrigateConfig
 from frigate.const import (
@@ -19,7 +20,6 @@ from frigate.const import (
 )
 from frigate.models import Event, Previews, Recordings, ReviewSegment
 from frigate.ptz.onvif import OnvifCommandEnum, OnvifController
-from frigate.types import PTZMetricsTypes
 from frigate.util.object import get_camera_regions_grid
 from frigate.util.services import restart_frigate
 
@@ -53,7 +53,7 @@ class Dispatcher:
         config: FrigateConfig,
         config_updater: ConfigPublisher,
         onvif: OnvifController,
-        ptz_metrics: dict[str, PTZMetricsTypes],
+        ptz_metrics: dict[str, PTZMetrics],
         communicators: list[Communicator],
     ) -> None:
         self.config = config
@@ -251,16 +251,16 @@ class Dispatcher:
                     "Autotracking must be enabled in the config to be turned on via MQTT."
                 )
                 return
-            if not self.ptz_metrics[camera_name]["ptz_autotracker_enabled"].value:
+            if not self.ptz_metrics[camera_name].autotracker_enabled.value:
                 logger.info(f"Turning on ptz autotracker for {camera_name}")
-                self.ptz_metrics[camera_name]["ptz_autotracker_enabled"].value = True
-                self.ptz_metrics[camera_name]["ptz_start_time"].value = 0
+                self.ptz_metrics[camera_name].autotracker_enabled.value = True
+                self.ptz_metrics[camera_name].start_time.value = 0
                 ptz_autotracker_settings.enabled = True
         elif payload == "OFF":
-            if self.ptz_metrics[camera_name]["ptz_autotracker_enabled"].value:
+            if self.ptz_metrics[camera_name].autotracker_enabled.value:
                 logger.info(f"Turning off ptz autotracker for {camera_name}")
-                self.ptz_metrics[camera_name]["ptz_autotracker_enabled"].value = False
-                self.ptz_metrics[camera_name]["ptz_start_time"].value = 0
+                self.ptz_metrics[camera_name].autotracker_enabled.value = False
+                self.ptz_metrics[camera_name].start_time.value = 0
                 ptz_autotracker_settings.enabled = False
 
         self.publish(f"{camera_name}/ptz_autotracker/state", payload, retain=True)