Fix NV12 crash issue when recreate camera object

MediaClient/media/video_decoder.cpp

@@ -575,8 +575,13 @@ void CVideoDecoder::Start() {
 }
 
 void CVideoDecoder::Stop() {
-    std::lock_guard<std::recursive_mutex> lock(_mutex);
-    m_bRunning = FALSE;
+    // Atomically signal the decoder to stop WITHOUT acquiring _mutex.
+    // decode() holds _mutex while inside avcodec_send_packet / CUDA calls
+    // that can block on the nvcuda64 SRW lock for a long time.
+    // If we waited for _mutex here, Stop() would deadlock whenever a
+    // concurrent decode() is stuck waiting for a CUDA operation held by
+    // an inference thread.
+    m_bRunning.store(FALSE, std::memory_order_release);
     log_print(HT_LOG_INFO, "%s, Video decoder stopped\r\n", __FUNCTION__);
 }