Last modified: 2013-09-29 14:21:34 UTC
Most mobile and tablet platforms include native, hardware-accelerated MP4/H.264 video support, and no Ogg Theora or WebM support. Transcoding all videos to MP4/H.264 would make it possible to view them on mobile web and mobile app platforms.
So this landed some time ago in TimedMediaHandler; still waiting on legal's clearance to use it on Wikimedia sites. :) (that's bug 39869)