Facebook has bought online video advert targeting firm LiveRail for reportedly between $400 and $500 million.

Founded in 2007, LiveRail currently claims the delivery of roughly 7 billion ad impressions a month with clients including Univision, PBS, Condé Nast Digital, CBS Interactive, ABC Family, Major League Baseball, A&E Networks, Gannett and Dailymotion.

“We believe that LiveRail, Facebook and the premium publishers it serves have an opportunity to make video ads better and more relevant for the hundreds of millions of people who watch digital video every month,” said Brain Boland, VP of ads product marketing and Atlas at Facebook, in a blog post.

“More relevant ads will be more interesting and engaging to people watching online video, and more effective for marketers, too.

“We’re just getting started with our partnership with LiveRail, but we’re very excited about the future for video publishers and marketers. We believe that LiveRail’s excellent product – known in the industry as a video supply-side platform or SSP – and Facebook’s expertise with relevancy, delivery and measurement will help us make video advertising much better for everyone.”