If it is like more an 'animated gif' than a video (only 8 frames and low fps) than you can use an animated shader.
Ok, I didn't understand a shit from that webpage (I'm not good coder). Btw, I got the key adding thing...
^^What I did understand, that is .shader file in .pk3 file. So, can someone try to explain me how i do it, or is there any good tutorial for noobs?
And, how to add it into map?
And I think I want to make it with trigger, like someone walks near it, and it starts to play... I gonna learn that myself, maybe looking example from Paint10 (or was it 9?)