IAB Digital Video Player-Ad Interface Definition (VPAID)
Recommended Digital Video Player-Ad Interface Definition guidelines from the Interactive Advertising Bureau (IAB). Available for free download in pdf format.
An overview, from the website:
This document establishes a Video Player-Ad API definition (VPAID) that standardizes the communication between video players and in-stream video advertising as designed by the Digital Video Committee of the Interactive Advertising Bureau (IAB). This standard intends to meet the needs of emerging in-stream ad formats such as: Non-linear video ads and Interactive video ads.
Visit IAB - Digital Video Player-Ad Interface Definition (VPAID)


