How to delay the ""--sout=#duplicate"???

[passionggg]

Hi,everyone
I am a freshman in the development of VLC. i use the vlc lib to read the rtsp streaming data from an IP camera.
The method is to setup a MFC project and libvlc. And then using the parameter "--sout=#duplicate{dst=file,dst=std{dst="C:\movie.avi"}}" to record the streaming video while display the IP camera streaming which using the "vmem".
But the problem is that I want to delay the recording after the streaming displaying has done 10 seconds. That is to say when the rtsp streaming from IP camera has displayed 10 seconds then start to record the video.
If anyone knows how to do, Please help me, thanks very much!!!