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Video Ad Serving Via VAST

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Historically, different proprietary video players used by different publishers had quite a few technical complexities, and thereby limiting the reach of digital video advertising campaigns.

To resolve this matter, the Interactive Advertising Bureau (IAB) introduced an XML-based specification known as VAST (Video Ad Serving Template). In my opinion, it’s a disruptive innovation that transformed the video advertising landscape. VAST facilitated interoperability by having a common in-stream advertising protocol for video players. The protocol is based on an universal XML schema for serving ads to digital video players. If your video player can accept the VAST template, then it can play any ad that follows the protocol, thus reducing expensive technical barriers and encouraging advertisers to increase their video ad spend.

VAST Calls from Video Player:

Normally the video player makes an ad request to the ad server, and the ad server directly serves the VAST response. Within the VAST response, there are various elements for Ad impressions and tracking events. The video player understands these events in a standardized way and reports such events back to the ad server.

Now let’s look at another scenario; the above scenario involves only one ad server but the fact remains that there can be multiple ad servers involved in serving the video ad. In this case, the video player first interacts with the primary server, gets a wrapper response and then hits one or more secondary servers to get the actual VAST XML. Since all the servers here will be interested in receiving tracking information, the video player pings each of them with tracking requests.

The diagram below illustrates how multiple ad servers serve Video Ads on the web pages.

Here are the sample elements in a VAST wrapper XML:

<VAST> <Ad> <Wrapper> …



…</Wrapper> </Ad> </VAST>

Different Types of Ads supported by VAST:

Linear Ads are the ones that you see before the content video begins (pre-roll), in the middle of the video (mid-roll) and at the end (post-roll). Usually in YouTube ads, you would see that the user is given an option to skip an advertisement after a few seconds. With 3.0 VAST Protocol, support for the ‘skip offset attribute’ (usually the value is 00:00:05), skip event and progress event has been introduced.

Master or Companion Ads provide a more engaging experience for the user. A Companion Ad is displayed at a specific location of the same web-page while the Master Ad is being played in the video player.

Non-Linear Ads are the ads overlaid on the top of video content. Using the VPAID technology, a more engaging user experience can be built, where the main video will get paused when user engages with a Video Ad and resumes when user cancels the ad.

The IAB has also come up with new Ad Units known as “Rising Stars”. Rising Stars have been a result of sustained efforts towards greater creativity in interactive advertising, and it encourages rich user engagement. More information on Video Rising Stars is outlined here.

With VAST 3.0, support for Ad Pods has been introduced. In this case, a series of ads can be played like TV commercials. This is accomplished by assigning a “sequence” attribute to the Ad element within a VAST 3.0 XML. The ads in an Ad Pod need to be linear but the last ad can have a non-linear creative. The placement an Ad Pod within a Video is outside the scope of VAST 3.0, but this can be accomplished by using VMAP where ad breaks can be specified within the content timeline by the content owners. You can read more about VMAP at iab.net/vsuite/vmap.

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