It won't work on all devices, but a h264 video encoded with the baseline profile should play fine on any phone or tablet sold in the past 5 years (maybe even ol

It won't work on all devices, but a h264 video encoded with the baseline profile should play fine on any phone or tablet sold in the past 5 years (maybe even older). On desktop, assuming the browser supports HTML5, it should be fine too. Just to be sure, offer at least one version of the video with VP8 just to cover weird cases where h264 isn't supported. You can also encode 480p, 720p, and 1080p versions for users on slow connections. Now, will it load on the original iPhone or IE 6? Maybe not - they'll see a link to the video file instead of a player - but not everyone needs to support legacy devices and browsers. YouTube, Vimeo, and other similar services are nice because they handle everything for you, but sometimes they become too expensive or are blocked. Depending on the type of user you have, <video> with a h264 video is cheaper and works well enough.