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VAST: video & audio

VAST - the Video Ad Serving Template - is the standard the IAB introduced to make video and audio 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 or audio player.

More information on VAST can be found here: https://www.iab.com/guidelines/vast/

How does it workwork?

A VAST call is a plain HTTPS exchange. The 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. [insert link to ad endpoint]

This XML document itself is put together by using advar templates [insert link] which give us the VAST markup, and creatives, where we upload the material itself. The template contains the static VAST markup and - if you want to use different types of video or audio - an extra template will need to be set up for each type. 

More on advar templates: https://documentation.adhese.org/books/templating/page/advar-templates

Simplified response example

<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>

Ad formats

Video types

Linear / in-stream

The ad plays in the video stream itself - before, during, or after the content. 

Outstream

The video ad appears in non-video environments, typically embedded in text-based content such as articles or news feeds. An outstream video could for example be shown in typical display placements such as a 'medium rectangle'. 

Non-linear

The ad runs alongside the content, typically as an overlay, without interrupting playback.

Extra functionality 

Companion ads

A companion ad is a display ad shown alongside a video or audio ad, usually displayed on top of the player or on its side. It is displayed at the same time as the master ad and offers the user a spot to click. It can continue to be displayed after the master ad has finished playing. 

Ad pods

The IAB VAST 3.0 template introduced the concept of Ad Pods. Ad Pods are a way to specify multiple <ad> elements, which are to be sequenced together and played back-to-back within a single ad break. Ad Pods are configured from VAST 3.0 compliant ad networks and passed to the JWX. Additionally, it is possible to create custom, static ad pods either using in-line VAST data or wrapped ad tags.

Audio

Native audio arrived in VAST 4.1, when the separate audio spec (DAAST) was folded back into VAST — before that, audio was served through DAAST as its own template.

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