• by Steve Smith  @popeyesm, December 17, 2013

After months of speculation and expectation, Facebook will launch its in-stream video ad program this week. The company gave its users and advertisers the heads-up in an official announcement this morning. Beginning this week, a limited number of users will see in their desktop and mobile newsfeeds an auto-playing promoted video for the upcoming film “Divergent.” According to the announcement, the short video will start playing as it comes into view on both a desktop and mobile feed. But like other Facebook video posts from users, the audio track will not run unless the user interacts with the clip. If tapped, the video will expand and run the audio track.

The model also includes a mechanism for discovering other streaming media. When the promoted video ends, it will present a carousel of two additional videos. For mobile devices, Facebook assures users that the video clips will not unexpectedly consume precious cellular data. “On mobile devices, all videos that begin playing as they appear on the screen will have been downloaded in advance when the device was connected to WiFi -- meaning this content will not consume data plans, even if you're not connected to WiFi at the time of playback,” the announcement states.

The arrival of video ads on Facebook has been expected for months, although the timing has been unclear. Even here, Facebook seems to be committing only to an initial test run among limited audiences.

The video ad rollout comes after Facebook has made a full court press among marketers to be seen as a viable rival for TV’s levels of scale and engagement. In a leaked document reported at TechCrunch and instructing Facebook ad tech partners on how to sell video, the company argues it has a prime-time reach of 70%, exceeding most cable networks. It argues that a video ad could reach the majority of Facebook users within just a few days. Likewise, the deck takes aim at online video kingpin YouTube for weak ad targeting and more interruptive formats. Facebook argues that its video ads, while in the feed, are engaged voluntarily by users.

Facebook is expected to roll out the video ad program in full early next year.