VAST 4.1 released for public comment

The IAB Tech Lab this month released VAST 4.1 for public comment, featuring advancements to the digital video ad serving template. Critical Updates to the Digital Video Ad Serving Template Include Support for Improved Ad Verification, Ad Creative Measurement, and Server-Side Ad Insertion & Integration of Audio Advertising.

“As the video landscape has evolved and grown, so have the technical complexities in delivery, measurement, and more,” said Dennis Buchheim, Senior Vice President, Technology and Ad Operations, IAB, and General Manager, IAB Tech Lab. “Once VAST 4.1 is adopted in the marketplace, we’ll see dramatically improved digital video and audio operations for buyers, sellers, and technical teams, making way for even greater growth for video.”

IAB says that “improved verification will allow for support within non-VPAID (Video Player-Ad Interface Definition) architecture, while also permitting VAST 4.1 to align with the Open Measurement Interface Definition (OMID) to better measure viewability of video ads on web. Upgrades for server-side ad insertion and the integration of DAAST (Digital Audio Ad Serving Template) are also elements of the proposed specification.”

Here the revisions:

  • Ad Requests: VAST 4.1 takes the first steps to standardizing ad requests through the use of macros, which will help propagate context more easily, especially for server-side ad insertion and server-to-server communications. Deprecating Video Player Ad Serving
  • Interface Definition (VPAID): While VPAID will continue to be used in the near future, VAST 4.1 takes the first steps to officially deprecate its use – significantly simplifying video ad execution and improving consumer experience.
  • AdServingID: A required field has been added to simplify comparing data about a video impression across the various systems involved with the delivery and tracking of the impression, enabling better measurement and more.
  • VAST Interactive Templates: Recognizing the need for standardizing interactive ads without ad delivered executable code, especially in mobile and OTT environments, VAST 4.1 introduces the concept of interactive templates.
  • Closed Captioning: VAST 4.1 enables closed captioning by standardizing the delivery of closed captioning files.
  • Flash: With VAST 4.1, all references to Flash and Flash resources are being removed, reflecting discontinuation of Flash usage in ads. VAST 4.1 is accompanied by OMID version 1.2 that adds support for web browsers and guidance to implement it for web browsers.

The public comment period will run through July 14, 2018, after which the IAB Tech Lab Digital Video Technical Standards Working Group will evaluate the comments received, make any necessary revisions, and release a final version. Comments are being accepted via email to