To display video ads, ensure that you're using one of the supported video ad formats on your site and that you've opted in to image ads. (View supported video ad formats on the Google AdSense Help Center.)
Important: Video ad inventory is limited at this time. As a result, you may not notice video ads on your site for a while until the inventory grows. In the meantime, we recommend opting in to both text and image ads to ensure you're maximizing your revenue potential.