Sort of, you can find the black splash screen image here:
and change that one, but the white one I'm pretty certain you'd have to compile yerself. I don't know about getting a video to work, but if you can it's going to be much more involved than replacing a file like in retropie.
Little side note- these guys are super nice, friendly, and helpful. I'm not saying deleting their splash makes you a baddie, but you might want to think about leaving a little something that says recalbox somewhere bud. Ya know out of respect for their hard work and all.