Authorized Buyers supports Skippable In-Stream Video Ads in both
VAST 2.0 and 3.0.

Authorized Buyers will not consider creatives to be skippable if they have skip
tracking URLs included under
`Ad/Wrapper/Extensions/Extension/CustomTracking` instead of under
`Ad/Inline/Extensions/Extension/CustomTracking`. Additionally,
because Authorized Buyers is unable to analyze the contents or functionality of a
VPAID ad, it cannot detect an ad's skip functionality if the ad is
implemented through VPAID.

Authorized Buyers supports skippable ads that use VAST 2.0 (through a custom
in-line skippable tracking element in the XML) or
[VAST 3.0](https://www.iab.net/vast)
with built-in skippable ad tracking functionality.

## How are skippable ads served?

When a skippable ad is served, the publisher player reads the VAST
response to determine if the ad has been implemented correctly as a
skippable ad and then displays a skippable button. The ad will be
displayed for at least five seconds before it can be skipped.

## Buyer requirements

OpenRTB uses `BidRequest.imp.video.maxduration` to indicate
maximum duration, and indicates skipability with a boolean
`BidRequest.imp.video.skip` field. Due to this structure, if an
impression accepts both skipable and non-skipable ads with different maximum
durations, a bid request can only represent one combination at a time. By
default, Google will use
[bid flattening](https://developers.google.com/authorized-buyers/rtb/get-started/request-guide#skippability-and-video-duration),
to indicate the different maximum durations for skipable and non-skipable ads
in separate bid requests. You can disable bid flattening by contacting your
account manager.

If bid flattening is disabled, `maxduration` would be set to
whichever value is lower between skipable and non-skipable maximum durations.

The following examples show how maximum duration for a skipable ad
opportunity is represented with and without bid flattening, assuming the
skipable maximum duration is `15` and the non-skipable maximum
duration is `60`.

| Example | `maxduration` | `skip` (true OR false) |
|---|---|---|
| Request without bid flattening | `15` | `true` |
| Flattened request #1: Non-skippable | `15` | `false` |
| Flattened request #2: Skippable | `60` | `true` |

The system periodically loads VAST tags to check whether they are skippable. In
between checks, the system assumes that the creative, uniquely identified by
`buyer_creative_id`, remains skippable or non-skippable as determined
by the previous check. Therefore, the policy is that skippable and non-skippable ads
cannot be rotated on the same `buyer_creative_id`.

> [!WARNING]
> **Warning** : Buyers found to be rotating skippable and non-skippable creatives on the same `buyer-creative_id` will face penalties up to and including account suspension.

## Requirements for VAST serving technologies

### Required new custom tracking event in VAST 2: `skip`

For Authorized Buyers to render an in-stream video creative as skippable, the VAST creative
must include at least one `Tracking` node under *Ad/Inline/Extensions/Extension/CustomTracking* ,
with the attribute `event="skip"`. The content of the node should be a
CDATA-wrapped URI that the video player will ping if the user clicks the skip button.

Here is an example:

```
<CustomTracking>
  <Tracking event="skip">
  <![CDATA[
    http://googleads.g.doubleclick.net/pageid/conversion/?ai=BYjRF3nOCTrCYG8_a-gbhkeDyAaKNvgYC6tiCpyDAjbcBsNsGEA
    IAQGyAQ93d3cueW91dHViZS5jb23IAQXaAShodHRwOi8vd3d3LnlvdXR1YmUuY29tL3ZpZGVvL3NFaHktU1hrTm8wuAIMyALS9s0eqAMBsAP
  ]]>
  </Tracking>
</CustomTracking>
```

For VAST 3, instead of a custom tracking extension, only the
`skip` event should be included.

### Optional new custom tracking event: `engagedView`

Authorized Buyers will also support `Tracking` nodes under *Ad/Inline/Extensions/Extension/CustomTracking*
with the attribute `event="engagedView"`. The content of these nodes should be a CDATA-wrapped
URI that the video player will ping when the user reaches the lesser of 30 seconds or video completion.

## Differences from TrueView

Skippable video ads on Authorized Buyers are not the same as TrueView ads and *cannot* be marketed to
your customers as such. Here are the primary differences between skippable video ads and TrueView:

- TrueView is only available through AdWords.
- TrueView is available on a Cost-per-View (CPV) basis, but Authorized Buyers skippable video ads are only available on a Cost-per-Impression (CPM) basis. Buyers may charge their customers on a CPV basis, but they will pay for the underlying skippable impressions on a CPM basis.
- TrueView ads increment the YouTube view count of the media file when users choose not to skip the ad, but Authorized Buyers skippable video ads do not, even when the media file is hosted on YouTube.
- TrueView media files must be hosted on YouTube. Authorized Buyers media files may optionally be hosted on YouTube. Contact your Technical Account Manager for more information about hosting the media files for your in-stream creatives on YouTube.
- Authorized Buyers skippable ads have a maximum length of 30 seconds.