minor fixes

README.md

@@ -320,10 +320,8 @@ ncnn 目前已在腾讯多款应用中使用，如：QQ，Qzone，微信，天
   recognition (i.e., speech-to-text); also support embedded devices and provide
   mobile Apps (e.g., Android App)
 
-| Speech recognition demo (Chinese + English)| Speech recognition demo (Chinese)|
-| ------------- | ------------- |
-| ![](https://user-images.githubusercontent.com/5284924/208226257-aaa8d62f-d339-4cfa-9db7-9b0de48ac70b.mp4) | ![](https://user-images.githubusercontent.com/5284924/208226272-02b80b15-cafc-4fc1-83ea-21fec6906335.mp4) |
-
+    - Speech recognition demo (Chinese + English): https://user-images.githubusercontent.com/5284924/208226257-aaa8d62f-d339-4cfa-9db7-9b0de48ac70b.mp4
+    - Speech recognition demo (Chinese): https://user-images.githubusercontent.com/5284924/208226272-02b80b15-cafc-4fc1-83ea-21fec6906335.mp4
 
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