Video background in Mozilla, Opera

We're using Restaurant version of Quark template, Quick Start package. In this package, video background in a module on homepage (table booking) is not working when Quick Start site is viewed in Mozilla and Opera, regardless of whether we're using the video that comes with Quick Start package or our own (stored on server). Only black background is shown. How can we fix this problem?

Could you please provide me with a URL to your website, either here or via PM (click the “Private Message” text underneath my avatar) so that I may analyze it? It is a lot easier for us to diagnose issues when we have a live site to examine.