capping ffmpeg stream error written

counter_live_rknn.py

@@ -7,6 +7,7 @@ Left / right rectangular zones mark the left and right sack feeders.
 A sack is counted once when its centroid enters a zone.
 """
 
+import contextlib
 import numpy as np
 import cv2
 import csv
@@ -14,6 +15,7 @@ import json
 import os
 import signal
 import socket
+import sys
 import threading
 import time
 from collections import deque
@@ -923,10 +925,37 @@ def start_control_socket():
     return srv
 
 
+@contextlib.contextmanager
+def _quiet_opencv_stderr():
+    """Silence OpenCV/FFmpeg stderr (DESCRIBE failed, cap.cpp WARN, etc.)."""
+    saved_fd = None
+    devnull_fd = None
+    try:
+        stderr_fd = sys.stderr.fileno()
+        saved_fd = os.dup(stderr_fd)
+        devnull_fd = os.open(os.devnull, os.O_WRONLY)
+        os.dup2(devnull_fd, stderr_fd)
+    except (AttributeError, OSError, ValueError):
+        yield
+        return
+    try:
+        yield
+    finally:
+        os.dup2(saved_fd, stderr_fd)
+        os.close(saved_fd)
+        os.close(devnull_fd)
+
+
 def open_capture(source):
     if source.lower().startswith(("rtsp://", "http://")):
         os.environ["OPENCV_FFMPEG_CAPTURE_OPTIONS"] = RTSP_FFMPEG_OPTIONS
-    cap = cv2.VideoCapture(source, cv2.CAP_FFMPEG)
+    # When STREAM_ERROR_LOG_MAX > 0, native OpenCV/FFmpeg stderr is suppressed;
+    # stream_error_log emits at most that many user-facing messages per outage.
+    if STREAM_ERROR_LOG_MAX > 0:
+        with _quiet_opencv_stderr():
+            cap = cv2.VideoCapture(source, cv2.CAP_FFMPEG)
+    else:
+        cap = cv2.VideoCapture(source, cv2.CAP_FFMPEG)
     cap.set(cv2.CAP_PROP_BUFFERSIZE, 1)
     return cap