On this note, I love the concept and the simple design but with all of that open real estate on the homepage you might consider one short explanatory blurb to greet visitors and pull them right in.
Don't take my word for it though - do A/B on your homepage with a video and with text and see which results in higher number of uploads, perhaps?
You guys have a terrific and unique service offering - one or two well-placed sentences (and perhaps a more link) will work wonders...