VASTlint
DAAST-1.0-mediafile-audio-type

DAAST-1.0-mediafile-audio-type

DAAST `<MediaFile>` type is a video MIME type — DAAST creatives are audio

WarningDAASTIAB DAAST 1.0 §3.2.2DAAST 1.0 and 1.1 (all DAAST documents)

Short answer

A video MIME type (e.g., video/mp4) on a DAAST <MediaFile> suggests the wrong asset was referenced. DAAST creatives are audio-only; the expected type is an audio MIME type such as audio/mpeg or audio/mp4.

Why this matters in production

This rule is a strong risk signal. Tags with this issue often still parse, but they become brittle across SDKs, SSAI resolvers, and CTV environments. DAAST rules validate the structural and semantic requirements specific to digital audio ad serving. Audio-specific fields like Category, AdInteractions, and audio MediaFile attributes are required by the spec and are absent from standard VAST validation. Affected scope: DAAST 1.0 and 1.1 (all DAAST documents).

Invalid

<MediaFile delivery="progressive" type="video/mp4">
  <![CDATA[https://cdn.example.com/ad.mp4]]>
</MediaFile>

Valid

<MediaFile delivery="progressive" type="audio/mpeg">
  <![CDATA[https://cdn.example.com/ad.mp3]]>
</MediaFile>
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Other DAAST rules

DAAST-1.0-root-versionRoot `<DAAST>` element must have a version attributeDAAST-1.0-root-version-value`<DAAST>` version attribute must be a recognised version string (`1.0` or `1.1`)DAAST-1.0-root-has-ad-or-error`<DAAST>` must contain at least one `<Ad>` or `<Error>`DAAST-1.0-ad-has-inline-or-wrapperEach DAAST `<Ad>` must contain exactly one `<InLine>` or `<Wrapper>`DAAST-1.0-inline-adtitleDAAST `<InLine>` must contain `<AdTitle>`DAAST-1.0-inline-impressionDAAST `<InLine>` must contain at least one `<Impression>`DAAST-1.0-inline-categoryDAAST `<InLine>` must contain `<Category>` (required in DAAST, unlike VAST)DAAST-1.0-inline-creativesDAAST `<InLine>` must contain `<Creatives>` with at least one `<Creative>`