Maximum Video Size??

Hello,

I'm working on a website design, with a main interactive video (chromakeyed).
The size of the video is 1080 (width) x 1500 (height) pixels. I've exported the video form After Effects to Flash, with the standard properties (File>Export>Adobe Flash Player(SWF)).
Now when I import the video in flash, the video plays in slow motion and not smooth at all...
Is it the size of the video that causes this problem? Is there a maximum size for video in flash?
I can't get it to play smoothly and I'm wondering if it's even possible to make this project work..
I hope one of you guys can help me with this!