I've done an update pass on the patch to TimedMediaHandler adding my ogv.js JavaScript Ogg Theora/Vorbis playback engine for IE 10/11 and Safari 6.1+ users:

https://phabricator.wikimedia.org/T63823

It now comes in two parts:

* https://gerrit.wikimedia.org/r/#/c/165477/ - libraries only
* https://gerrit.wikimedia.org/r/#/c/165478/ - TMH modifications for desktop only

(I wasn't happy with the mobile video overlay in the third patch and have abandoned it for now, will rewrite it soon but want to sync up with mobile web team on integration issues.)

This version should pretty much "just work" on desktops/laptops, including seeking, and the JS console spam should be gone now. If folks have strong preferences on my plugin code, do let me know and I will tweak further. :)

I have a live wiki running at http://ogvjs-testing.wmflabs.org/ -- note that thumbnail images of some videos there are broken due to some kind of InstantCommons issue but the actual video plays through.

-- brion