This object represents the most general type of impression. Although the term “banner” may have very specific meaning in other contexts, here it can be many things including a simple static image, an expandable ad unit, or even in-banner video (refer to the Video object in Section 3.2.7 for the more generalized and full featured video ad units). An array of Banner objects can also appear within the Video to describe optional companion ads defined in the VAST specification.

The presence of a Banner as a subordinate of the Imp object indicates that this impression is offered as a banner type impression. At the publisher’s discretion, that same impression may also be offered as video, audio, and/or native by also including as Imp subordinates objects of those types. However, any given bid for the impression must conform to one of the offered types.