• by Gavin O'Malley  @mp_gavin, March 24, 2015

Following Facebook's lead, Twitter is testing auto-play video ads among consumers with iPhones and other iOS-supported devices.

“We’re running a small test on a few variations on the video playback experience,” according to the micro-blogging giant.

For the time being, select Twitter users will see complete videos play in a loop, while others can expect to receive a looped six-second teaser. In each test case, the videos will be muted until users choose to tap on them, at which point the video screen will also expand.

Long a growth engine for digital advertising, video has become increasingly key to the fortunes of social giants like Facebook and Twitter. Indeed, video will drive Twitter’s advertising business in 2015, according to a recent report from the equity research team at J.P. Morgan.

The move -- first reported by Ad Age on Monday -- is part of a broader video push by Twitter.

The social network just acquired live-streaming app Periscope -- a deal that reportedly set the company back between $50 million to $100 million.

Earlier this month, Twitter also rolled out an embedded video widget for publishers. With the widget, publishers can highlight Twitter-hosted video on their sites. The new feature relies on the same JavaScript used to render Tweet buttons and embedded Tweets.

To better team up advertisers with social media influencers, Twitter also recently bought Niche, a start-up that teams up advertisers with social media influencers, and Vine influencers in particular. Launched in late 2013, Niche started working with Twitter and Vine soon after.

In addition to matching content creators with brands, Niche offers free cross-platform analytics. Financial terms of the deal were not disclosed, but reports put it at around $30 million.

In 2015, “Twitter … will likely become an increasingly important form of engagement for brands given the ability to communicate with consumers in real-time and now to utilize video more effectively on the platform,” the team at J.P. Morgan predicted.

Despite its promise, Twitter only recently introduced a video platform. Videos can be 30 seconds long and be uploaded, edited and shared directly from Twitter’s flagship platform.

At least on the surface, rivals say they welcome increased competition from Twitter and other video newcomers. At a recent industry event, Robert Kyncl, YouTube’s head of content, estimated the digital video market to be worth between $200 billion and $400 billion -- more than enough to go around, he said.

While estimating that a more modest $7.7 billion will go to digital video, this year, eMarketer suggested that 2015 is shaping up to be the year that social and video truly converge.