diff --git a/reproject/alert.py b/reproject/alert.py
index ccc54ee..4df414e 100644
--- a/reproject/alert.py
+++ b/reproject/alert.py
@@ -1,5 +1,3 @@
-
-
 import os
 import queue
 import threading
@@ -18,11 +16,15 @@ class Alert:
         self.encode_thread = None
         self.upload_thread = None
         self.stop_event = threading.Event()
-        self.abort_event = threading.Event()  # 新增：用于超时强制中断
         self.dropped_frames = 0
+        self.accepting_frames = False
+        self.ended = False
 
     def start(self, width=1920, height=1080, fps=30):
         print(f"Starting alert with {width}x{height}")
+        self.accepting_frames = True
+        self.ended = False
+        self.stop_event.clear()
         read_fd, write_fd = os.pipe()
         self.read_pipe = os.fdopen(read_fd, "rb", buffering=0)
         self.write_pipe = os.fdopen(write_fd, "wb", buffering=0)
@@ -55,23 +57,17 @@ class Alert:
         self.stream.width = width
         self.stream.height = height
         self.stream.pix_fmt = "yuv420p"
-        self.stream.options = {"preset": "ultrafast", "tune": "zerolatency", "crf": "23"}
+        # 使用更快的编码预设
+        # self.stream.options = {"preset": "ultrafast", "crf": "23"}
         print("AV container and stream initialized")
 
         # 启动编码线程
         def _encode() -> None:
             try:
                 print("Encode thread starting")
-                # 修改循环条件：增加 abort_event 检查
                 while not self.stop_event.is_set() or not self.frame_queue.empty():
-                    if self.abort_event.is_set():
-                        print("Encode thread aborted by timeout (dropping remaining frames)")
-                        break
-                    
                     try:
                         frame = self.frame_queue.get(timeout=0.1)
-                        if frame is None:
-                            break
                         av_frame = av.VideoFrame.from_ndarray(frame, format="bgr24")
                         for packet in self.stream.encode(av_frame):
                             self.container.mux(packet)
@@ -88,6 +84,8 @@ class Alert:
         self.encode_thread.start()
 
     def provide_frame(self, frame):
+        if not self.accepting_frames or self.ended:
+            return
         try:
             self.frame_queue.put(frame, block=True, timeout=0.05)
         except queue.Full:
@@ -99,16 +97,22 @@ class Alert:
                 )
 
     def end(self):
+        if self.ended:
+            return
+        self.ended = True
+        self.accepting_frames = False
         print(
             f"Stopping alert, queued frames: {self.frame_queue.qsize()}, dropped frames: {self.dropped_frames}"
         )
-        self.frame_queue.put(None)
         self.stop_event.set()
 
-        # 等待编码线程完成（不设超时，确保所有帧都编码完成）
+        # 等待编码线程完成
         if self.encode_thread:
             self.encode_thread.join()
-            print(f"Encode thread completed with {self.frame_count} frames")
+            if self.encode_thread.is_alive():
+                print("Warning: Encode thread still running")
+            else:
+                print(f"Encode thread completed with {self.frame_count} frames")
 
         # 完成编码，flush所有待处理的数据
         try: