diff --git a/client/ScreenSpy.cpp b/client/ScreenSpy.cpp
index 178865d..f68c4af 100644
--- a/client/ScreenSpy.cpp
+++ b/client/ScreenSpy.cpp
@@ -145,10 +145,19 @@ CScreenSpy::~CScreenSpy()
 
 LPBYTE CScreenSpy::GetFirstScreenData(ULONG* ulFirstScreenLength)
 {
+    if (m_hTargetWnd && IsIconic(m_hTargetWnd)) {
+        *ulFirstScreenLength = 0;
+        return nullptr;
+    }
     ScanScreen(m_hFullMemDC, m_hDeskTopDC, m_ulFullWidth, m_ulFullHeight);
     m_RectBuffer[0] = TOKEN_FIRSTSCREEN;
     LPBYTE bmp = scaleBitmap(m_BmpZoomBuffer, (LPBYTE)m_BitmapData_Full);
     memcpy(m_FirstBuffer, bmp, m_BitmapInfor_Send->bmiHeader.biSizeImage);
+    // H264/AV1：不发原始位图，IDR 到达后服务端自行解锁；节省每次切窗口的流量峰值
+    if (m_bAlgorithm == ALGORITHM_H264) {
+        *ulFirstScreenLength = 0;
+        return nullptr;
+    }
     memcpy(1 + m_RectBuffer, bmp, m_BitmapInfor_Send->bmiHeader.biSizeImage);
     if (m_bAlgorithm == ALGORITHM_GRAY) {
         ToGray(1 + m_RectBuffer, 1 + m_RectBuffer, m_BitmapInfor_Send->bmiHeader.biSizeImage);
diff --git a/server/2015Remote/ScreenSpyDlg.cpp b/server/2015Remote/ScreenSpyDlg.cpp
index ef7bb8f..b143be5 100644
--- a/server/2015Remote/ScreenSpyDlg.cpp
+++ b/server/2015Remote/ScreenSpyDlg.cpp
@@ -1478,6 +1478,11 @@ VOID CScreenSpyDlg::DrawNextScreenDiff(bool keyFrame)
             if (!m_bHide) {
                 if (Decode((LPBYTE)NextScreenData, NextScreenLength)) {
                     bChange = TRUE;
+                    // 解码成功即代表 IDR 参考帧已建立（编码器首帧强制 IDR），解除门控。
+                    // 不依赖 IsAnyKeyframe：某些硬编输出格式或解码器首帧 EAGAIN 延迟会导致
+                    // 关键帧检测误判，进而让 m_bIsFirst 永久为 TRUE（"请等待"卡死）。
+                    if (m_bIsFirst)
+                        m_bIsFirst = FALSE;
                 }
             }
             // Broadcast video frame to web clients (only for Web session dialogs)