# VAST



# VAST Video

VAST (Video Ad Serving Template) is a video ad served inside a publisher's own video player. Instead of shipping a fixed-size creative, you supply one video and the player renders it in whatever slot it has available.

That single point drives most of the specs below: because the player controls the frame, aspect ratio matters and pixel dimensions do not.

#### Two ways to supply the creative

A VAST video campaign can be set up either by uploading the video file to Eskimi, or by pointing Eskimi at a VAST tag hosted on the client's ad server.

<table border="1" id="bkmrk-option-what-you-supp" style="border-collapse: collapse; width: 100%; height: 88.2423px;"><colgroup><col style="width: 33.3582%;"></col><col style="width: 33.3582%;"></col><col style="width: 33.3582%;"></col></colgroup><thead><tr style="height: 29.4141px;"><td style="height: 29.4141px;">Option</td><td style="height: 29.4141px;">What you supply</td><td style="height: 29.4141px;">When to use it</td></tr></thead><tbody><tr style="height: 29.4141px;"><td style="height: 29.4141px;">Upload an MP4</td><td style="height: 29.4141px;">The video file itself, uploaded to Eskimi. Eskimi generates the VAST response.</td><td style="height: 29.4141px;">The default. Use it whenever you have the raw creative and no third-party ad server is involved.</td></tr><tr style="height: 29.4141px;"><td style="height: 29.4141px;">External VAST URI</td><td style="height: 29.4141px;">A remote VAST tag URL from the client's ad server (Campaign Manager, Flashtalking and similar).</td><td style="height: 29.4141px;">When the client serves and measures the creative from their own ad server, or needs to swap the creative without re-trafficking.</td></tr></tbody></table>

- The two behave differently once the campaign is live, so it is worth knowing which one you are working with:  
    The specs below apply to MP4 uploads. With an External VAST URI the creative lives on the client's ad server, so they own the file type, ratio, size and duration — Eskimi cannot validate or change it. Send them the specs before they traffic the tag.
- Skip offset is not editable on an External VAST URI. The "Skip after seconds" field only affects uploaded MP4s; with a remote tag the skip behaviour comes from the client's VAST response.
- Tag-wrapped third-party measurement is not supported on an External VAST URI. See "Third-party tracking" below.

#### Creative specifications

<table border="1" id="bkmrk-attribute-what-to-us" style="border-collapse: collapse; width: 100%; height: 205.899px;"><colgroup><col style="width: 33.3333%;"></col><col style="width: 33.3333%;"></col><col style="width: 33.3333%;"></col></colgroup><thead><tr style="height: 29.4141px;"><td style="height: 29.4141px;">Attribute</td><td style="height: 29.4141px;">What to use</td><td style="height: 29.4141px;">Required or recommended</td></tr></thead><tbody><tr style="height: 29.4141px;"><td style="height: 29.4141px;">File type</td><td style="height: 29.4141px;">MP4</td><td style="height: 29.4141px;">Required</td></tr><tr style="height: 29.4141px;"><td style="height: 29.4141px;">Aspect ratio</td><td style="height: 29.4141px;">16:9 (landscape) or 4:3</td><td style="height: 29.4141px;">Required</td></tr><tr style="height: 29.4141px;"><td style="height: 29.4141px;">Resolution</td><td style="height: 29.4141px;">720p is a good default; 1080p is fine too</td><td style="height: 29.4141px;">Recommended</td></tr><tr style="height: 29.4141px;"><td style="height: 29.4141px;">File size</td><td style="height: 29.4141px;">Up to 5 MB</td><td style="height: 29.4141px;">Recommended</td></tr><tr style="height: 29.4141px;"><td style="height: 29.4141px;">Duration</td><td style="height: 29.4141px;">From 5 sec. upwards — no fixed cap</td><td style="height: 29.4141px;">See "Video duration"</td></tr><tr style="height: 29.4141px;"><td style="height: 29.4141px;">Fixed pixel dimensions</td><td style="height: 29.4141px;">Not applicable — the player scales the creative to the placement</td><td style="height: 29.4141px;">-</td></tr></tbody></table>

The two things people get wrong:

- There is no required pixel size. Older versions of this article listed dimensions such as 320x480 or 1024x768. Ignore them — VAST creatives adapt to the placement, so only the aspect ratio needs to be correct.
- 5 MB is a recommendation, not a rule. A file above 5 MB will still run; it just loads more slowly, which can cost you impressions and completions on slower connections. Keep it under 5 MB when you can, but do not reject a creative for being larger.

##### Aspect ratio

Aspect ratio is the spec that actually needs to be right. Supply the video in one of the following:

<table border="1" id="bkmrk-aspect-ratio-typical" style="border-collapse: collapse; width: 100%;"><colgroup><col style="width: 33.3333%;"></col><col style="width: 33.3333%;"></col><col style="width: 33.3333%;"></col></colgroup><thead><tr><td>Aspect ratio</td><td>Typical placement</td><td>Notes</td></tr></thead><tbody><tr><td>16:9</td><td>Desktop and mobile in-stream, landscape players</td><td>The most widely supported ratio — use this if you only produce one version</td></tr><tr><td>4:3</td><td>Older / legacy players</td><td>Accepted, but reaches less inventory than 16:9</td></tr></tbody></table>

A creative in the different ratio is not rejected, but the player will letterbox or pillarbox it — black bars top and bottom, or down the sides. Anything important near the edges of the frame can end up cropped or visually cramped, so keep logos, legal text and the CTA well inside the safe area.

#### Video duration

There is no single maximum duration, and no length that is right for every campaign. What to use depends on the trade-off you want to make.

##### What the format supports

- Under 5 sec. — serves as a non-skippable ad.
- 5 sec. and above — serves as a skippable ad (see "Skip offset" below).
- No fixed cap. A large share of bid requests accept up to 30 sec., and a meaningful share accept 30–60 sec. Longer creatives can run, but on progressively fewer placements.

##### The trade-off

Length pushes two things in opposite directions:

- Available inventory. The shorter the video, the more placements it can serve on. A publisher that only accepts up to 30 sec. will not bid on a 45 sec. creative, so scale narrows as duration grows.
- Video completion rate (VCR). The longer the video, the smaller the share of users who watch it to the end. Internal comparisons have seen roughly 82% VCR on 10 sec. creatives against around 50% for a standard-length VAST video.  
    So a long creative is a legitimate choice when the message needs the time and the campaign is measured on something other than completions. If VCR or scale is the KPI, shorter wins. Decide the length from the KPI, not from a spec sheet.

#### Skip offset

Skippability is a lever worth using deliberately. If a video can be skipped at 5 sec., a large share of users will skip it there — and the brand message never lands. Eskimi lets you move or remove that skip point.  
Set it in the "Skip after seconds" field when you upload the MP4. Note that this field has no effect on an External VAST URI — a remote tag carries its own skip offset, set by the client's ad server.

- 5 — the default: the user can skip after 5 sec.
- 0 — no skip option at all; the ad is non-skippable.
- Up to 30 — the protocol ceiling for the skip offset itself. This is a limit on when the skip button may appear, not a limit on how long the video may be.

Pushing the skip point out protects the message but reduces the number of players willing to serve the ad, and users who cannot skip are more likely to abandon the content. Treat 0 as a deliberate choice for a short creative rather than a default.

[![image.png](https://manual.eskimi.com/uploads/images/gallery/2026-08/scaled-1680-/vFCoiorPcgbyLwsf-image.png)](https://manual.eskimi.com/uploads/images/gallery/2026-08/vFCoiorPcgbyLwsf-image.png)

#### Third-party tracking

A 1x1 tracking pixel can be added to any VAST video campaign. VAST does not support JavaScript tags, so the pixel is the standard route — but it only reports impressions to third-party platforms such as Integral Ad Science.  
To measure anything beyond impressions — viewability, brand safety, IVT — the VAST video has to be wrapped in a third-party tag.

#### VAST Examples

[![vast-example.png](https://manual.eskimi.com/uploads/images/gallery/2026-08/scaled-1680-/jVaH2z8GFVpzX2Ty-vast-example.png)](https://manual.eskimi.com/uploads/images/gallery/2026-08/jVaH2z8GFVpzX2Ty-vast-example.png)

[![vast-example-2.png](https://manual.eskimi.com/uploads/images/gallery/2026-08/scaled-1680-/3l1FCLku4Dk9CBJN-vast-example-2.png)](https://manual.eskimi.com/uploads/images/gallery/2026-08/3l1FCLku4Dk9CBJN-vast-example-2.png)

# Remote VAST URI

##### **How to upload Video Remote VAST URI:**

**Step 01:** Log in to your DSP account &gt; go to "***Creative Sets"*** &gt; and click "***Add creative set"***.

[![1.png](https://manual.eskimi.com/uploads/images/gallery/2025-06/scaled-1680-/DjlsVSBgVxJoJunU-1.png)](https://manual.eskimi.com/uploads/images/gallery/2025-06/DjlsVSBgVxJoJunU-1.png)

**Step 02:** Give the Creative set a name &gt; select the Creative Format "**Video**" &gt; select the video format as "**Video Remote VAST URI**"

[![2.png](https://manual.eskimi.com/uploads/images/gallery/2025-06/scaled-1680-/t1JHx3r1XrK0v53z-2.png)](https://manual.eskimi.com/uploads/images/gallery/2025-06/t1JHx3r1XrK0v53z-2.png)

  
**Step 03:** Paste the creative tag in the box and hit save button (*Tick Tracking if there is any*):

[![3.png](https://manual.eskimi.com/uploads/images/gallery/2025-06/scaled-1680-/HwvnRHNxjzKElwnV-3.png)](https://manual.eskimi.com/uploads/images/gallery/2025-06/HwvnRHNxjzKElwnV-3.png)

**\*\*\* N/B:** *Viewability tracking method VPAID and OMID should be automatically selected. If not, make sure to select cause it will affect the viewability tracking in the reporting.*

---

# How to upload Video ads?

**Step 1:** Log in to your DSP account, go to Creative Sets, and on the new page click "Add creative set".

[![image-1613663648296.png](https://manual.eskimi.com/uploads/images/gallery/2021-02/scaled-1680-/image-1613663648296.png)](https://manual.eskimi.com/uploads/images/gallery/2021-02/image-1613663648296.png)

[![image-1613663832858.png](https://manual.eskimi.com/uploads/images/gallery/2021-02/scaled-1680-/image-1613663832858.png)](https://manual.eskimi.com/uploads/images/gallery/2021-02/image-1613663832858.png)

**Step 2:** On the next page indicate the creative sets Title and select the format.

[![image-1705394175513.png](https://manual.eskimi.com/uploads/images/gallery/2024-01/scaled-1680-/1OIVeuDNf7BprhDD-image-1705394175513.png)](https://manual.eskimi.com/uploads/images/gallery/2024-01/1OIVeuDNf7BprhDD-image-1705394175513.png)

**Step 3:** Select the type of video (VAST + IBV, VAST, IBV).

[![image-1705394241911.png](https://manual.eskimi.com/uploads/images/gallery/2024-01/scaled-1680-/wgUFfOentcFoJSQP-image-1705394241911.png)](https://manual.eskimi.com/uploads/images/gallery/2024-01/wgUFfOentcFoJSQP-image-1705394241911.png)

**Step 4:** Choose file to use as creative

**Step 5:** Select Viewability tracking method (VPAID - for websites inventory, OMID for in-app inventory) both can be selected.

**Step 6:** if needed - update "Skip after seconds" value. For some exchanges this is a required value (i.e. DC), default is 5s.

[![image-1705394296959.png](https://manual.eskimi.com/uploads/images/gallery/2024-01/scaled-1680-/UB1YZSsrEDSvvlxj-image-1705394296959.png)](https://manual.eskimi.com/uploads/images/gallery/2024-01/UB1YZSsrEDSvvlxj-image-1705394296959.png)

**Not necessary:** Upload companion banners. Companion banner should be one from most popular sizes: 300x250px, 320x480px, or 480x320px.  
**Not necessary:** Add description and Call to action text. Default CTA is "Lear more" and this is changed only in placements, which support that. It will describe a call to action button for the destination URL.

**Step 7:** Save your video ad.

# VAST Video Wrapping, Upload & Execution

##### **Introduction**

Wrapping a VAST (Video Ad Serving Template) URI into a 3rd party VPAID (Video Player Ad-Serving Interface Definition) tag offers several advantages in the digital advertising ecosystem.

Firstly, by utilising a VPAID tag, advertisers gain access to enhanced interactivity and engagement features for their video ads. VPAID enables the inclusion of interactive elements like clickable overlays, interactive games, and surveys within the ad unit, providing a richer user experience.

Secondly, wrapping the VAST URI in a VPAID tag allows for seamless integration with various video players and ad-serving platforms, ensuring compatibility and widespread distribution across different environments.

Additionally, the VPAID tag provides a standardized API for tracking and reporting ad metrics such as viewability, ad interactions, and performance data, enabling advertisers to make data-driven optimizations and measure the effectiveness of their video ad campaigns accurately.

Overall, wrapping a VAST URI into a 3rd party VPAID tag enhances ad interactivity, facilitates widespread ad distribution, and enables comprehensive ad measurement and optimization capabilities.

---

##### **Practical implications**

To wrap a VAST (Video Ad Serving Template) URI into a 3rd party VPAID (Video Player Ad-Serving Interface Definition) tag, you need to follow a specific process.

**Retrieve the VAST URI from the ad source**, which typically represents the XML-based ad response. To retrieve the necessary URI you need to first setup your video campaign on Eskimi DSP. The VAST URI will be found in the campaign's approval page under the Creatives section. Check the screenshot below:

[![Screenshot 2023-05-19 at 16.35.14.png](https://manual.eskimi.com/uploads/images/gallery/2023-05/scaled-1680-/H2qxCbspypGlTHv5-screenshot-2023-05-19-at-16-35-14.png)](https://manual.eskimi.com/uploads/images/gallery/2023-05/H2qxCbspypGlTHv5-screenshot-2023-05-19-at-16-35-14.png)

**Remember:** If you are planning to wrap the VAST URI into the MOAT, IAS or any other 3rd party tracker, you will need to provide VAST URI until **&amp;preview=1**. Also please add in the end of the URL **&amp;vastVersion=2** this will open more available inventory later, when delivering campaign.

**Remember:** The original video campaign **can't** be deleted, expired or rejected. Leave it in pending status until the actual campaign ends.

**If you need to upload a 3rd party VPAID tag,** it is necessary to select **Remote VAST URI** as your video type and paste the VAST URI as usual. Such VPAID tags will only run on VPAID compliant environment - mostly web publishers. To know more about VPAID check our comprehensive guide: [https://manual.eskimi.com/books/creatives/page/a-comprehensive-guide-to-vpaid-web-advertising](https://manual.eskimi.com/books/creatives/page/a-comprehensive-guide-to-vpaid-web-advertising)

[![Screenshot 2023-05-19 at 16.53.17.png](https://manual.eskimi.com/uploads/images/gallery/2023-05/scaled-1680-/hm7F5YJQj7Gbf6KN-screenshot-2023-05-19-at-16-53-17.png)](https://manual.eskimi.com/uploads/images/gallery/2023-05/hm7F5YJQj7Gbf6KN-screenshot-2023-05-19-at-16-53-17.png)

**Remember:** you can select VPAID viewability tracking method which will wrap the VPAID tag into Eskimi tag. By doing so advertisers will be able to track viewability on Eskimi DSP.

It is necessary understand that such method will cause timeouts of retrieving the original video file from the tag, because of this the preview page (only) will not work, but the campaign will run as usual.

[![Screenshot 2023-05-22 at 08.42.11.png](https://manual.eskimi.com/uploads/images/gallery/2023-05/scaled-1680-/jZBB7dtc9Jikqs33-screenshot-2023-05-22-at-08-42-11.png)](https://manual.eskimi.com/uploads/images/gallery/2023-05/jZBB7dtc9Jikqs33-screenshot-2023-05-22-at-08-42-11.png)

**If you need to upload a 3rd party VAST tag (OMID tag)**, then you will need to upload the original VAST mp4 and add the OMID tag under *Verification wrapper URL.*

*[![Screenshot 2023-05-19 at 16.57.41.png](https://manual.eskimi.com/uploads/images/gallery/2023-05/scaled-1680-/Hf1aJYr4CrC0QvBM-screenshot-2023-05-19-at-16-57-41.png)](https://manual.eskimi.com/uploads/images/gallery/2023-05/Hf1aJYr4CrC0QvBM-screenshot-2023-05-19-at-16-57-41.png)*

**Remember:** You will need to change the VAST URI located in the tag to *{vast\_url\_enc}*.

**Remember:** That for such setup you can enable OMID viewability tracking method.

Afterwords, **set up the campaign** as usual.

---

#### **Troubleshooting**

Before any upload we recommend to first upload the VPAID/VAST tag into VAST video validator: [https://googleads.github.io/googleads-ima-html5/vsi/. ](https://googleads.github.io/googleads-ima-html5/vsi/)This is a universally used tool that allows to instantly see if the tag will be rendering properly, if all the metrics are being fired and receive errors.

# VAST Video placement types/tracking options.

All the options that we can track in bid request for VAST Videos are in the pictures below.

[![image-1632303032934.png](https://manual.eskimi.com/uploads/images/gallery/2021-09/scaled-1680-/RyYR2qmdZckPcFJ7-image-1632303032934.png)](https://manual.eskimi.com/uploads/images/gallery/2021-09/RyYR2qmdZckPcFJ7-image-1632303032934.png)