Micro-blogging site Twitter is trialling a new video ad format which will allow brands to extend the reach of their video content and seeks revenue opportunities from the growing video advertising market.

Promoted videos, which will be marked in the timeline by a 'promoted' banner, will appear in a similar way to Twitter’s video cards in users’ feeds. Videos do not run automatically, but are instead started by a user click.

Twitter will begin selling promoted video ads on a cost per view basis to its managed service advertisers across the globe. Marketers will also have access to analytics such as completion percentage and a breakout of organic versus paid video views. Promoted video is not currently available to small businesses.

Writing in a post on the Twitter blog, the company’s senior product manager of TV and video David Regan says prior tests of the updated organic Video Card format have shown that tweets containing native Twitter video generate better engagement and more video views than before.

Digital video advertising spend in the UK is set to increase by 107 per cent year on year to £673m in 2014, according to eMarketer, highlighting marketers’ growing appetite for the format.

As marketers increasingly turn to video advertising, the Internet Advertising Bureau is currently preparing the launch of a baseline metric to state the length of a video ad a user needs to have seen before it can qualify as an impression as the trade body looks to make buying inventory across the web more comparable with traditional media.

In May Facebook announced it was bringing its Premium Video ads format to the UK, which plays video ads automatically as users scroll through their news feeds.

Jed Hallam, head of social strategy at media agency Mindshare, says brands should be demanding a deep level of insights on the user interactions with video content, following the latest video ad format launch.

He added: "Given both Twitter and Facebook’s depth of user data, it’s really important that they both start providing brands with insights deeper than aggregate view volume and length of video watched.

"From an insights perspective, I want to know who watched the content, their other interests, their likely demographic, and other more in-depth user behaviour information. Then, from a technology point of view, I want to be able to structure video content across paid, and earned in such a way that we can truly achieve sequential storytelling."