VAST
If a publisher wishes to serve ads to video players, it must develop distinct video ad tags based on each video player's technology. The IAB has created a standard for video advertising, VAST, which allows for scalable delivery of ads to video players from different vendors.
VAST enables ad servers to utilise a single ad response format, independent of the video player's technology. The video player must be capable of requesting and parsing XML documents. Therefore, by utilising XML, VAST serves as a universal solution for video ad serving, comparable to HTML for browser-based ad serving.
Since the initial release of VAST, online video technology has advanced, enabling more sophisticated possibilities for online video advertising. To support this evolution, VAST has been enhanced with additional features and functionality. VAST 4.0 represents the current industry standard.
Adhese fully supports VAST: we are compliant with VAST 2.0, 3.0, and 4.0 and can help you adopt its guidelines.
More info about the VAST standard can be found on IAB's website