Stream Video Player "captions.xml"

Is there something I should know about the captions file? I don’t have much knowledge about php, html….
Does it bother if i don’t have an HD version of the video?

Is there anything specifically I should know? (When I tried to upload I got a ‘missing folder’ message. I’ve asked the host to make a temporary so that problem is solved?!)

Greets and thanks

http://wordpress.org/extend/plugins/stream-video-player/