Facebook starts rolling out video ads in News Feeds

Premium Video Ads that Facebook began testing at the end of last year are being gradually integrated into accounts of its more than 1.2 billion members, product marketing manager Susan Buckner said in an online post.

"Brands now have another way of engaging people on Facebook with compelling video experiences," Buckner said.

"We'll roll out Premium Video Ads slowly and monitor how people interact with them."

The 15-second video ads play automatically when they pop-up in news feeds and are designed for advertisers who want to reach large audiences with sight, sound and motion, according to Facebook.

(Also see: Facebook begins testing auto-playing video ads on users' news feeds)

Facebook did not disclose rates, but online reports indicated daily spots aimed at wide numbers of members at prime times could cost as much as $2.5 million a day.

"Premium Video Ads are bought and measured in a way that's similar to how advertisers already buy and measure ads on TV," Buckner said.

Facebook has teamed with a company called Ace Metrix to measure such creative components of ads as watchability, meaningfulness and "emotional resonance."

Facebook said it is working with a small set of advertisers at the start to develop high-quality campaigns.

New video ads should begin appearing in Facebook members' news feeds on desktop computers and mobile devices over the course of the next few months, according to Buckner.