VAST: video & audio

VAST - the Video Ad Serving Template - is the standard the IAB introduced to make video ad serving work across players from different vendors. It uses an XML schema to carry an ad's metadata from the ad server to the video player.

Without a shared standard, a publisher would have to build a separate ad tag for every player technology it runs. VAST removes that: the ad server returns one response format, and any player that can request and parse XML can act on it. In that sense VAST is to video ad serving what HTML is to the browser - a universal layer that everything agrees on.

How does it work

A VAST call is a plain HTTPS exchange. The video player requests an ad from the ad server using a simple URL, and Adhese answers with a VAST XML document the player knows how to read.

Example response:

<VAST version="4.0">
  <Ad id="19787">
    <InLine>
      <AdSystem>Adhese</AdSystem>
      <AdTitle>Your creative</AdTitle>
      <Impression><![CDATA[ …/impression ]]></Impression>
      <Creatives>
        <Creative>
          <Linear>
            <Duration>00:00:15</Duration>     
            <TrackingEvents>              
              <Tracking event="start"> … </Tracking>
              <Tracking event="firstQuartile"> … </Tracking>
              <Tracking event="complete"> … </Tracking>
            </TrackingEvents>
            <VideoClicks>
              <ClickThrough><![CDATA[ …/click ]]></ClickThrough>
            </VideoClicks>
            <MediaFiles>                  
              <MediaFile type="video/mp4" width="640" height="360">
                <![CDATA[ …/creative.mp4 ]]>
              </MediaFile>
            </MediaFiles>
          </Linear>
        </Creative>
      </Creatives>
    </InLine>
  </Ad>
</VAST>