Ad tech companies AppNexus and Unruly have announced mutual support of the industry’s first open-source header bidding solution for outstream video through open-source library and community prebid.js.

The solution enables all publishers to auction outstream video inventory with customisation and control across desktop and mobile, and optimise revenue through direct transactions with premium demand partners in a fair and transparent auction.

Unruly’s user-friendly outstream formats can be run on any publishing platform, including those that do not produce their own video content.

Its viewability-initiated players can run on desktop, mobile vertical video and in 360, and puts the user in control. AppNexus outstream formats, designed for low-latency, high-impact desktop and mobile delivery, support HTML5 and VPAID 2.0, with more than 30 publisher attributes to allow customisation for every client.

Unruly and AppNexus units can be used together in real time auctions to maximize revenue and opportunity for publishers.

Prebid.js now makes it possible to traffic outstream video using ‘renderers’ – a client-side code (a combination of JavaScript, HTML and CSS) responsible for displaying a creative on a page.

A renderer for outstream ads provides a player environment capable of playing a video creative (most commonly, a VAST XML document) with ability to support volume, pause, and play controls for the user, full screen, skippability controls, vendor-specific text, colour schemes or logos, expansion/collapse player actions, and more.

Demand partners develop their own renderers with the pre-bid framework, allowing video to be delivered to display slots.

Eric Hoffert, senior vice president of video technology at AppNexus, said header bidding for outstream inventory is good for the video ecosystem.

“It drives the video liquidity marketers need, empowers publishers of all kinds with full visibility and control over the video monetisation of their inventory, and offers an engaging, user-friendly experience,” he said.

“This results in a virtuous cycle that powers a vibrant open video internet.”

Kenneth Suh, executive vice president of global business development at Unruly, said: “By combining the transparency of header bidding with user-friendly formats like outstream, publishers are able to tackle some of their biggest challenges head on.

“With the launch of the first open-source header bidding solution for outstream, publishers should feel confident that they’re providing the best user experience while maximising their revenue potential.”

Both Unruly and AppNexus’ adapters are now available in beta on prebid.org. Additional video demand adapters are expected to become available in the second half of the year.