please tell me if its possible to add a video on my website without using youtube facility. i mean just let my video auto play on the open page?
of course it's possible, but how you go about it depends on the type of site you have. You wouldn't be asking this if your site was hand coded though. Then it's relatively easy. Bear in mind though the size of the video file, format, copyright etc.
I'm guessing you use either website builder, Wordpress or managed Wordpress. I wouldn't know for these applications.
If you are using a hand coded site, it will take your developer a true 10 minutes most, to do it if he/she has ready access to all needed files and site.