VAST-2.0-mediafile-delivery
VAST-2.0-mediafile-delivery
<MediaFile> must have a delivery attribute
ErrorRequired fieldsIAB VAST 2.0 §2.4.1VAST 2.0 and later (all versions)
Short answer
Every <MediaFile> must declare how it is delivered via the delivery attribute. The valid values are progressive (HTTP download) and streaming (live stream protocol such as HLS/DASH).
Why this matters in production
This rule is usually a delivery blocker. Many players, SDKs, and ad servers will discard the response or skip the affected creative once this condition is hit. Required-field failures usually stop validation early because the platform cannot determine the basic shape of the ad, the creative metadata, or the mandatory tracking payload. Affected scope: VAST 2.0 and later (all versions).
How to fix
Add delivery="progressive" for HTTP-served files (MP4, WebM) or delivery="streaming" for live protocols (HLS, DASH).
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