HTML5 uses a native <video> tag, and currently there's two camps supporting different codecs. Mozilla Foundation supports the Ogg Theora video codec because their licensing, and Apple/Google support H.264 encoded videos - which is a patented and licensed technology costing people that serve up, encode and whatnot sometimes up to $5 million per year. Think DVD's basically... each machine sold pays a license fee to the DVD Consortium. Hope that helps.