VAST tracking events / Linear
VAST midpoint tracking event
Short answer: Fires when linear playback reaches 50 percent of Duration.
When it fires
The playhead has reached half of the declared Duration. Ship it with the rest of the quartile set even when nobody reads the middle value, so reporting can split stall from skip from completion.
Where it is valid
| 2.0 | 3.0 | 4.0 | 4.1+ |
|---|---|---|---|
| Yes | Yes | Yes | Yes |
Legal containers: Linear. An event in the wrong container is not a player error. It is a URL nobody calls.
Using it in a tag
<TrackingEvents>
<Tracking event="midpoint">
<![CDATA[https://track.example.com/midpoint]]>
</Tracking>
</TrackingEvents>VAST XML fragment only. This excerpt belongs inside a complete VAST document, so standalone validation will fail until it is wrapped in a full <VAST>response.
Related vastlint rules
- VAST-2.0-linear-tracking-quartiles: <Linear> has no standard quartile tracking events — measurement system receives no signal
- VAST-4.1-tracking-event-value: Tracking event attribute not in the valid set for this VAST version
Related events
- firstQuartile: Fires when linear playback reaches 25 percent of Duration.
- thirdQuartile: Fires when linear playback reaches 75 percent of Duration.
- complete: Fires when linear playback reaches the end of Duration.
Check the XML, then confirm the beacons fire
Validate the event names and containers on the document. Test a live URL when the XML is clean and reporting is still empty.