self hosting video

I got some questions about self hosting videos. I understand that I need the pro version.

1 Do I upload a video version for every quality that I would like to offer?

2 Can the plugin auto detect quality based on the visitor′s internet connection speed or is it manual selection only?

3 What about buffering? Can the video start playing before it′s downloaded? Will the buffering stop at a certain point when the visitor pause the video or will it continue to download until the full video is downloaded?

4 Can I use only one codec to get backward compatibility (a couple of years) and get OS independent (android, windows, Iphone, Mac)? Or do I need to upload the video in two codecs?

5. Is there by any chance a demo web page where I can test the plugin pro version?

Thanks!