We know that Facebook have delayed the introduction of video ads because of concerns their users will find them disruptive and/or irritating but they are at least starting the testing process via mobile versions of the social networking site. Selected users are now seeing video ads in their news feeds. These will be silent, so less intrusive, but if the user taps the video it will go to full screen with full sound.
Facebook is limiting the testing control group to individual users and those with verified accounts. They'll only see videos from other users, not from advertisers or brands. Facebook provided a very short video to demonstrate the trial. No further information was given by the site in their blog post but as the Christmas shopping looms ever nearer, they'll want to get this feature live on the main site for all users as soon as possible.