Knowledge base

Supported creative formats

Unified Auction supports mobile static display ad (HTML) and video ad (VAST) formats. This article outlines specifications and best practices for Demand Side Platform (DSP) partners.

Static display ads

Static display, display interstitial, and display ads refer to the same ad format in Unity, as these are commonly used for interstitial Placements with static graphic assets. This format typically uses an image with a hyperlink or click event to a destination URL from the advertiser. For example:

<a href=""><img src="https://ad-image.jpg"></a>

Static display ad specs

The following are requirements for display ad formats:

  • Content must be formatted as a snippet of HTML (or JS) code, not as a full HTML document or web page.
  • If the content was created with JavaScript only, it must be wrapped with <script> tags.
  • The Unity SDK renders ad markup within the webview as full-screen on mobile devices. However, the advertising partner is responsible for scaling and centering content. Unity loads content to the top-left corner by default. To avoid this, use CSS to center your content in various mobile screen sizes.

Unity highly recommends taking advantage of information available in the Unified Auction bid request to send assets that are optimized for the device, platform, and network connection represented in the request.

Example display ad

Example of HTML with hyperlink:

<style>html, body { margin: 0; padding: 0; width: 100%; height: 100%; vertical-align: middle; } html { display: table; } body { display: table-cell; vertical-align: middle; text-align: center; -webkit-text-size-adjust: none; } </style><a href=""><img src="" width="320" height="480"></a><img height="1" width="1" src="">

Example of HTML with JS script:

<script src=""><script><style>some css style</style><img src="https://impression-pixel-url">

Video ads

Video Ad Serving Template (VAST) is a universal XML schema for serving ads to digital video players. Unity supports VAST 3.0 (standards developed and maintained by the Internet Advertising Bureau (IAB)), and is backwards compatible with 2.0, with the exception of some features.

How VAST works in Unity

A typical VAST XML template contains:

  • Impression and Error URLs to track each event.
  • Information on the video length, and URLs for hosted assets.
  • Video-tracking URLs for video start, first quartile, midpoint, third quartile, and completion events.
  • Click-tracking URLs and destination URLs for video click events.
  • Optional companion ad information for the video asset, tracking, and click-through URLs.

Important: The Unity SDK parses VAST XML to retrieve video media files and fire relevant tracking URLs. Properly formatted XML with the correct media assets is critical, otherwise the SDK will fail to render the ad despite receiving the VAST bid response.

Video ad specs

The following are requirements for video ads:

  • Unity supports VAST 2.0 and 3.0 for linear video with an optional companion ad.
  • VAST InLine contains all the required elements to render a video ad.
  • VAST Wrapper points to another VAST XML, with a max wrapper depth of 5.
  • Supported video media files include:
    • MIME type only 'video/mp4' for both iOS and Android.
    • Video duration under 40 seconds. The video duration tag is required, in HH:MM:SS format.
    • Video file sizes less than 20 MB.
  • Unity supports companion ads that appear after the initial video ad completes:
    • <StaticResource> as an image/jpeg, image/jpg, image/gif, or image/png.
    • <HTMLResource> as a "snippet" of HTML code.
  • For click events, the click-through URL should be a single item, while the click-tracking URL may be multiple items.
    • Landscape dimensions are 480 x 320 pixels.
    • Portrait dimensions are 320 x 480 pixels.
  • For error reporting, Unity fires an <Error> tracking URL with an associated error code:
    • 100: XML parsing error
    • 20x: Duration or size unsupported
    • 30x: Wrapper-related errors
    • 40x: Media file-related errors
    • 60x: Companion ad-related errors
    • 90x: Any other undefined error
  • Unity does not support ad pods, non-linear ads, or industry icons from 3.0.

Best practices

  • For an example VAST XML schema, please see the example XML format below.
  • Limit VAST wrapper redirection to 2-3. Check the final URL points for the appropriate VAST XML file.
  • Include 'bitrate', 'delivery', 'type', 'width', and 'height' as tag attributes.
  • Recommended video file size is under 5 MB for users with WiFi connections, and 2 MB for users with cellular connections, with bitrates of 512 kbps or lower. The Unity SDK calculates video file size from bitrate and duration.

Open Measurement specs

Unity Ads supports Open Measurement-capable creatives. To format your creatives for OM in VAST:

  • For VAST versions 4.1 and higher, include <AdVerifications> in the VAST tag. For VAST versions 4.0 or lower, include AdVerifications> as an <Extension> under <Extensions>.
  • In the <Verification> tag, include the following:
    • Your vendor key, which is used to identify whether your verification script must receive any additional parameters.
    • Your verification script inside the <JavaScriptResource> tag.
    • <VerificationParameters> are optional.

For example:

    <Verification vendor="">
        <JavaScriptResource apiFramework="omid" browserOptional="true">
            <!CDATA[verification params key value pairs]]>

For more information, see the IAB documentation on VAST 4.1 Open Measurement support.

OM verification script guidelines

  • Register session observers, video, and ad events as soon as the script runs (this simplifies event management and ensures that all events are called in order).
  • When registering the session observer, always include a vendor key that matches the vendor='key' attribute in your <Verifications> node.
  • See this example of a simple verification script.

Common issues

If your bid response wins an auction but your creatives don’t show an impression or send tracking events, here are some possible reasons to investigate:

  • Blank XML: The returned XML from Wrapper VASTTagURI is blank or malformed.
  • XML parsing error: Missing required tag elements like <VAST>, <Duration>, or <MediaFile>.
  • Video file size too large: The available <MediaFile> in video/mp4 is over 20 MB.
  • Video duration too long: Duration exceeds 40 seconds.

Example XML formats

Example VAST Linear ad with Companion in <InLine>:

<VAST version="3.0">
    <Error id="to-track-error"><![CDATA[http://error-tracking-url]]></Error>
    <Ad id="ad_id">
            <AdTitle>ad title</AdTitle>
            <Impression id="to-track-impression"><![CDATA[http://impression-url]]></Impression>
            <Error id="to-track-error"><![CDATA[http://error-tracking-url]]></Error>
                        // start, firstQuartile, midepoint, thirdQuartile, complete, mute, unmute
                            <Tracking event='start'><![CDATA[http://tracking-url]]></Tracking>
                            <MediaFile delivery='progressive' width='16' height='9' type='video/mp4' bitrate='600' apiFramework='NONE'><![CDATA[https://media_file_site.your_file.mp4]]>
                            //  ... multiple media files per quality
                <CompanionAds>  // For end card
                    <Companion>   // Static resource asset only usually image file
                        <StaticResource creativeType="image/jpeg">
                            <![CDATA[end card url]]>
                            <Tracking event='creativeView'><![CDATA[https://endcard_tracking]]></Tracking>

Example VAST in <Wrapper>:

<VAST version="2.0">
    <Ad id="1234">
            <VASTAdTagURI><![CDATA[http://vast-ad--url]]></VASTAdTagURI>  // point to inline xml

Unity VAST error codes

Error code Description
100 XML parsing error.
101 Schema validation error.
102 Unsupported version.
200 Unsupported format.
202 The video duration is too long or is not formatted properly (HH:MM:SS).
203 The size is unsupported.
300 General wrapper error.
301 Wrapper URI timeout
302 The wrapper depth limit was reached. Unity tries a maximum of 5 routes to fetch VAST content through VASTAdTagURI.
303 No ads were found in Wrapper
400 Unable to play linear.
401 The supported video media file was not found in the media URL
402 The media file timed out.
403 The received media files are unsupported. Make sure they are 'video/mp4' type with a maximum file size of 20 MB.
404 The media file url is not supported in iOS. Make sure it uses HTTPS protocol.
499 The media file is missing a valid ClickThrough URL under <VideoClicks>.
600 The Companion Ad (end card) has a general error.
601 The Companion Ad (end card) size is unsupported. The minimum image size is 320 x 480 pixels (portrait) or 480 x 320 pixels (landscape).
602 The Companion Ad (end card) is unable to display.
603 Unable to fetch the Companion Ad (end card).
604 A valid Companion Ad (end card) resource URL was not found.
699 The Companion Ad (end card) does not contain a valid ClickThrough URL.
900 Undefined error.
901 General VPAID error.
998 Invalid URL.
999 Unknown error.
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Last updated on 22nd Oct 2021