There seems to be a problem with reverting to previous versions of particularly big files; the one I encounter is with a 2.35 GiB Ogv file: https://commons.wikimedia.org/wiki/File:Vladimir_Putin%27s_press_conference_on_2012-12-20.ogv
After clicking on the 'revert' link in the file history box, I'm getting the following error message...
Internal error Unexpected value: ‘oldimage’=‘’. Return to Main Page.
... and nothing happens, I still cannot revert to the previous version of the file.