Website video creation service, Flixpress is a groundbreaking service where you can create high-end video and animation online in your website browser, ideal for animated templates, after effects templates and photo galleries. Create unique high-end video from our animated templates in your web browser.

They offer some free templates you can use and i assume this service allows you to upload your own videos to overlay. the licensing terms are really strict and you need to look at them before using the service.