Unruly / Blog / What Are Video Ad-Serving Template (VAST) Tags And Wrappers? Let’s Break It Down

What Are Video Ad-Serving Template (VAST) Tags And Wrappers? Let’s Break It Down

This week we’re taking a look at the complexities of VAST technology and how multiple wrappers can operate within a chain from video file to ad file.

There are additional complications that can make this process more challenging, including when creatives get served with a VPAID wrapper, but for now, we’ll start with the basics.


What is VAST?

VAST stands for “Video Ad Serving Template” and was created by the Interactive Advertising Bureau (IAB) in 2008. Essentially it’s a uniform template that structures ad tags and metadata which are then transferred from the ad server to a video player.

This enables ad servers from different companies to use a standardized tag format across multiple publishers/video players, allowing any ad server to deliver a video ad into any compatible player.

One of the final things to happen in the video ad serving chain is a link to a VAST file being delivered to technology that can render VAST ads. This could be Unruly’s In-Stream or In-Article ad units, for example.


OK, got it. What’s a VAST wrapper?

Within the VAST file there may be several sets of tracking pixels from vendor A, B, C (and so on)’s wrappers. So vendor A (which could be the creative) will layer on its own tracking pixels, perhaps video impressions.

From there it’ll take vendor B’s wrapper (in this case, let’s say it’s a DSP) with its own tracking pixels for video completion and quartiles, for example.

And then it could move into an SSP like UnrulyX with – you guessed it – our own tracking pixels, until we finally get to the unit itself. It’s then the ad unit’s responsibility to comprehend the complexities within each wrapper and therefore fire the accompanying pixels as it plays the video unit.

An added layer of complexity comes when VPAID wrappers are embedded into VAST wrappers, but that’s a blog post for another day. Stay tuned and we’ll cover that soon.