[Plugin: Viper's Video Quicktags] remove black bars

hi!
great plugi, searched log for it!
the only question i have is: why are there black bars in top and beneath my video? the video is 640×360 and the vimeo settings of the plugin are also 640×360 -> so how is it possible that there are the bars and how can i remove them?

http://delusions.at/

(page is under construction)
thanks and best regards
ernst

http://wordpress.org/extend/plugins/vipers-video-quicktags/