diff --git a/frigate/video/detect.py b/frigate/video/detect.py
index d1048e4270..f55c1c9635 100644
--- a/frigate/video/detect.py
+++ b/frigate/video/detect.py
@@ -144,6 +144,11 @@ class CameraTracker(FrigateProcess):
 
     def run(self) -> None:
         self.pre_run_setup(self.log_config)
+
+        # OpenCV only sees small images here, and its default per-core thread
+        # pool burns ~5x the CPU of running them inline
+        cv2.setNumThreads(1)
+
         frame_queue = self.camera_metrics.frame_queue
         frame_shape = self.config.frame_shape
 
diff --git a/frigate/video/ffmpeg.py b/frigate/video/ffmpeg.py
index c4364f8d71..16e3afcdb5 100644
--- a/frigate/video/ffmpeg.py
+++ b/frigate/video/ffmpeg.py
@@ -79,7 +79,8 @@ def capture_frames(
         frame_name = f"{config.name}_frame{frame_index}"
         frame_buffer = frame_manager.write(frame_name)
         try:
-            frame_buffer[:] = ffmpeg_process.stdout.read(frame_size)
+            if ffmpeg_process.stdout.readinto(frame_buffer) != frame_size:
+                raise EOFError("incomplete frame")
         except Exception:
             # shutdown has been initiated
             if stop_event.is_set():