Fix blnak live stream

counter_live_rknn.py

@@ -1384,11 +1384,14 @@ 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(
+                ok, 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())
+                if ok:
+                    tmp_path = f"{LIVE_STREAM_FRAME_PATH}.tmp"
+                    with open(tmp_path, "wb") as f:
+                        f.write(jpeg.tobytes())
+                    os.replace(tmp_path, LIVE_STREAM_FRAME_PATH)
             except Exception:
                 pass