fix : live view buffering

counter_live_rknn.py

@@ -1002,6 +1002,18 @@ def draw_popups(img, popups, frame_idx):
     return alive
 
 
+def _write_live_frame_atomic(path, jpeg_bytes):
+    """Write JPEG atomically so dashboard readers never see a partial file."""
+    dest = Path(path)
+    dest.parent.mkdir(parents=True, exist_ok=True)
+    tmp = dest.with_suffix(dest.suffix + ".tmp")
+    with open(tmp, "wb") as f:
+        f.write(jpeg_bytes)
+        f.flush()
+        os.fsync(f.fileno())
+    os.replace(tmp, dest)
+
+
 def connect_stream(source, warmup=WARMUP_FRAMES):
     attempts = 0
     while not shutdown_requested:
@@ -1381,12 +1393,10 @@ def run():
 
         if LIVE_STREAM_ENABLED and frame_idx % LIVE_STREAM_EVERY_N == 0:
             try:
-                Path(LIVE_STREAM_FRAME_PATH).parent.mkdir(parents=True, exist_ok=True)
                 _, jpeg = cv2.imencode(
                     ".jpg", frame, [cv2.IMWRITE_JPEG_QUALITY, LIVE_STREAM_QUALITY]
                 )
-                with open(LIVE_STREAM_FRAME_PATH, "wb") as f:
-                    f.write(jpeg.tobytes())
+                _write_live_frame_atomic(LIVE_STREAM_FRAME_PATH, jpeg.tobytes())
             except Exception:
                 pass