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/video.py

@@ -11,6 +11,7 @@ import time
 import cv2
 from setproctitle import setproctitle
 
+from frigate.camera import CameraMetrics, PTZMetrics
 from frigate.comms.config_updater import ConfigSubscriber
 from frigate.comms.inter_process import InterProcessRequestor
 from frigate.config import CameraConfig, DetectConfig, ModelConfig
@@ -28,7 +29,6 @@ from frigate.object_detection import RemoteObjectDetector
 from frigate.ptz.autotrack import ptz_moving_at_frame_time
 from frigate.track import ObjectTracker
 from frigate.track.norfair_tracker import NorfairTracker
-from frigate.types import PTZMetricsTypes
 from frigate.util.builtin import EventsPerSecond, get_tomorrow_at_time
 from frigate.util.image import (
     FrameManager,
@@ -386,7 +386,9 @@ class CameraCapture(threading.Thread):
         )
 
 
-def capture_camera(name, config: CameraConfig, shm_frame_count: int, process_info):
+def capture_camera(
+    name, config: CameraConfig, shm_frame_count: int, camera_metrics: CameraMetrics
+):
     stop_event = mp.Event()
 
     def receiveSignal(signalNumber, frame):
@@ -398,15 +400,14 @@ def capture_camera(name, config: CameraConfig, shm_frame_count: int, process_inf
     threading.current_thread().name = f"capture:{name}"
     setproctitle(f"frigate.capture:{name}")
 
-    frame_queue = process_info["frame_queue"]
     camera_watchdog = CameraWatchdog(
         name,
         config,
         shm_frame_count,
-        frame_queue,
-        process_info["camera_fps"],
-        process_info["skipped_fps"],
-        process_info["ffmpeg_pid"],
+        camera_metrics.frame_queue,
+        camera_metrics.camera_fps,
+        camera_metrics.skipped_fps,
+        camera_metrics.ffmpeg_pid,
         stop_event,
     )
     camera_watchdog.start()
@@ -421,8 +422,8 @@ def track_camera(
     detection_queue,
     result_connection,
     detected_objects_queue,
-    process_info,
-    ptz_metrics,
+    camera_metrics: CameraMetrics,
+    ptz_metrics: PTZMetrics,
     region_grid,
 ):
     stop_event = mp.Event()
@@ -437,7 +438,7 @@ def track_camera(
     setproctitle(f"frigate.process:{name}")
     listen()
 
-    frame_queue = process_info["frame_queue"]
+    frame_queue = camera_metrics.frame_queue
 
     frame_shape = config.frame_shape
     objects_to_track = config.objects.track
@@ -469,7 +470,7 @@ def track_camera(
         object_detector,
         object_tracker,
         detected_objects_queue,
-        process_info,
+        camera_metrics,
         objects_to_track,
         object_filters,
         stop_event,
@@ -542,17 +543,14 @@ def process_frames(
     object_detector: RemoteObjectDetector,
     object_tracker: ObjectTracker,
     detected_objects_queue: mp.Queue,
-    process_info: dict,
+    camera_metrics: CameraMetrics,
     objects_to_track: list[str],
     object_filters,
     stop_event,
-    ptz_metrics: PTZMetricsTypes,
+    ptz_metrics: PTZMetrics,
     region_grid,
     exit_on_empty: bool = False,
 ):
-    fps = process_info["process_fps"]
-    detection_fps = process_info["detection_fps"]
-    current_frame_time = process_info["detection_frame"]
     next_region_update = get_tomorrow_at_time(2)
     config_subscriber = ConfigSubscriber(f"config/detect/{camera_name}")
 
@@ -589,8 +587,8 @@ def process_frames(
                 break
             continue
 
-        current_frame_time.value = frame_time
-        ptz_metrics["ptz_frame_time"].value = frame_time
+        camera_metrics.detection_frame.value = frame_time
+        ptz_metrics.frame_time.value = frame_time
 
         frame = frame_manager.get(
             f"{camera_name}{frame_time}", (frame_shape[0] * 3 // 2, frame_shape[1])
@@ -660,8 +658,8 @@ def process_frames(
             # ptz_moving_at_frame_time() always returns False for non-autotracking cameras
             if not motion_detector.is_calibrating() and not ptz_moving_at_frame_time(
                 frame_time,
-                ptz_metrics["ptz_start_time"].value,
-                ptz_metrics["ptz_stop_time"].value,
+                ptz_metrics.start_time.value,
+                ptz_metrics.stop_time.value,
             ):
                 # find motion boxes that are not inside tracked object regions
                 standalone_motion_boxes = [
@@ -839,7 +837,7 @@ def process_frames(
             continue
         else:
             fps_tracker.update()
-            fps.value = fps_tracker.eps()
+            camera_metrics.process_fps.value = fps_tracker.eps()
             detected_objects_queue.put(
                 (
                     camera_name,
@@ -849,7 +847,7 @@ def process_frames(
                     regions,
                 )
             )
-            detection_fps.value = object_detector.fps.eps()
+            camera_metrics.detection_fps.value = object_detector.fps.eps()
             frame_manager.close(f"{camera_name}{frame_time}")
 
     motion_detector.stop()