YouTube image size very large – Sento Free

I am using the free version of Sento and am including videos on my pages by pasting the URL from YouTube or Vimeo. The result is a video frame size that spans the width of the whole page and is much larger than when it plays native on those hosts.

Is this the way the theme is supposed to render video files? I would prefer to have them smaller, and have tried adjusting the frame size in Media -> Settings but that doesn’t help. Here is an example of what I’m talking about:
http://cheklich.com/blog/client-work/

Thank you in advance.