How to distinguish WMDRM protected files from normal ones?   

Hi there,

I wonder to know how to distinguish the WMDRM protected files from
normal wma/wmv.
I mean, how to know whether this file is protected in header.
Is there anyone know that.

Thanks in advance,
Andy

date: Wed, 17 Jun 2009 00:40:15 -0500   author:   AndyTsao