No Firefox support? That seems pretty arbitrary; why not show my browser the page and let it decide if it can render it?
Oh yeah, it's by a web designer...
Oh yeah, it's by a web designer...
And I think in general, letting average folk see something half finished and probably broken will totally prejudice their opinions of the final product. Irrational, but true.
AAPL and GOOG can use VIDEO tag for H.264-encoded video.
Mozilla and Opera can use VIDEO tag for Ogg Theora encoded video.
There are two distinct implementations: VIDEO/H.264 and VIDEO/Theora. Neither supports the other.
You got suckered by the "'HTML5' VIDEO" talk. Not your fault; even its proponents didn't address such video basics until it became too late.