How to resize mp4 animation in top header?

How can I set width and height of an mp4 animation in a top header?
At my under-construction site, wiserworldweb.org , when we try to place an animated log in the top header, it will go in but at small size. We need it much bigger.
The primary theme is commonsinabox, which is responsive, but we also have the plugin "Responsive Add Ons."
We are using rtMedia.
The animated log has the following characteristics:
File URL: http://wiserworldweb.org/wp-content/uploads/2014/05/logo_red3_5_18_mpg4.mp4
File name: logo_red3_5_18_mpg4.mp4
File type: MP4 (video/quicktime)
File size: 679 kB
Length: 0:08
Bitrate: 695kb/s
Dimensions: 1280 × 720
The file resizes fine when played on differing screen sizes in Windows Media Player.
The WPMU plugins are as follows:
Installed WPMU DEV Plugins
Name Links Installed Version Latest Version Actions
Chat
The best stand-alone live chat WordPress plugin by a mile - does absolutely everything you could ask for, and more... Installation & Use Instructions
Configure
2.0.8.3 2.0.8.3

MarketPress eCommerce
The best premium WordPress eCommerce plugin available - packed with features and no extensions required. Installation & Use Instructions
2.9.4.3 2.9.4.4
Auto Update

Ultimate Facebook
The ultimate plugin for integrating advanced social sharing features into your WordPress site. Installation & Use Instructions
Configure
2.6.6 2.7
Auto Update

Appointments +
The most powerful, flexible and feature-rich bookings plugin available for WordPress. Appointments + does it all. Installation & Use Instructions
Configure
1.4.3.1 1.4.3.1

WPMU DEV Dashboard
Get one-click installs and upgrades of all WPMU DEV plugins and themes, immediate access to support and the community - all from the comfort of WordPress. Installation & Use Instructions
Configure
3.4.4 3.4.4

Wiki
Turn any WordPress site into a fully functional, easy to use, wiki. You can even create multiple wikis on one site. Installation & Use Instructions
Configure
1.2.5 1.2.5

Does anyone have any advice?
Thank you.
Jock