VAST 4.0 Updates
The updates made in VAST 4.0 and the challenges they address are summarized here:
● Separate Video File and Interactive File: The complexity of digital video has given rise to the need to separate the linear video file from any creative interactive API
files. While the VAST media file has accepted a variety of media files in the past, interactive APIs cannot always be executed. A VAST tag that provides the video file
separate from APIs can display more successfully across platforms and devices. The Interactive File standard is expected to be Secure Interactive Media Interface
Definition (SIMID) – which is a replacement for VPAID focused on interactivity.
● Server-Side Ad Insertion Support: While client-side ad execution and tracking has been the recommended way to track ad impressions and other metrics, digital instream video and audio ads are often served to devices (clients) that cannot execute and track ads using traditional display methods. VAST 4 supports the increasingly
common “ad-stitching” method for stitching linear ads into a video or audio content stream and sending it to players with limited capabilities.
● Mezzanine File: To support advertising across video platforms that include longform content and high-resolution screens, VAST 4 features include support for the
raw, high-quality mezzanine file. The mezzanine file is very large and cannot be used for ad display, but ad-stitching services and other ad vendor use it to generate
files at appropriate quality levels for the environment in which they play.
● Ready-to-Serve Files: Along with support for including the mezzanine file, VAST 4 provides guidance on providing three ready-to-serve media files, each at different
quality levels, to ensure that a linear video/audio ad can always play. The IAB Digital Video Ad Format Guidelines offers guidance on video/audio file specifications for
● Universal Ad ID: While VAST has offered a creative identifier in the past, it has been used inconsistently. The new Universal Ad ID feature is used specifically for
including a creative identifier that is maintained across systems. The existing adId attribute for creative can still be used to log creative IDs specific to the server.
● Ad Verification and Viewability Execution: Verification vendors have been using VPAID for measurement verification instead of using it for ad interaction as VPAID
was intended. VAST 4 offers a designated space () for inserting ad verification APIs, enabling a more streamlined process for executing files strictly
intended for ad verification. Open Measurement (OM) is expected to be used for this purpose. In addition, a secondary impression element, the
element, has been added to allow publishers the option to track viewability on their inventory.
● Support for Categories: Ad categories help publishers separate competing ad creative and improve brand safety. VAST 4 ad categories support these efforts.
● Conditional Ad Declaration: In programmatic environments, a VPAID unit is sometimes used to decide whether or not to place an ad. If this “conditional ad”
never results in an ad to display, the publisher may have to forfeit any revenue from the resulting lost inventory. A declaration in VAST for a conditional ad helps
publishers prevent and reclaim any potentially lost inventory revenue in programmatic ad delivery. Note – VPAID & this element are being deprecated as of
VAST 4.1 since VPAID is being replaced by SIMID (Secure Interactive Media Interface Definition) and OMID (Open Measurement Interface Definition.
● New Error Codes: Along with support for the mezzanine file and other new features, added error codes provide additional troubleshooting support.
● Standardized Timestamp: Trackers used in VAST often include timestamp macros, but its use has not been consistent. In VAST 4, the [TIMESTAMP] macro and the
format for time has been standardized to enable more consistent time-sensitive tracking.