What Are Vast Tags and How to Create Them?

April 13, 2021
What Are Vast Tags and How to Create Them?

Video ads have seen tremendous growth over the years, which can be directly attributed to publishers adopting VAST. 

In fact, ad spending in video advertising is expected to reach $35 billion by 2024 from its current amount at $26 billion. Many publishers are leveraging programmatic video advertising as a means to increase their revenue.

So what is VAST? And what are its benefits?

In this article, we will cover the definition and history of VAST Tags, and how to create them.

What Is a Video Ad Serving Template (VAST)?

Developed in 2008 by the Interactive Advertising Bureau (IAB) in response to the increase in video advertising, Video Ad Serving Template or VAST is the standard for structuring ad tags that serve ads to video players. Using eXtensible Markup Language (XML) schema, VAST transfers metadata from the master video ad slot.

Put simply, VAST is a script designed to allow video players and ad servers to communicate with each other effectively, ensuring a video ad will play in the expected manner, providing a seamless experience for the consumer.

A Video Ad Serving Template instructs video players how to retrieve an ad, when to render the ad, the ad media, along with the ad length, format, duration, tracking information, and pricing.

For digital publishers utilizing video advertising, VAST and VAST Ad Tags allow the seamless implementation of video ads. When a video player understands VAST, it is able to play third-party video ads, regardless of the publisher's ad server or ad network, thus simplifying the video ad experience.

How Does Vast Work?

VAST request Diagram

As demonstrated in the above image, VAST operates using three simple processes.

1. VAST Request

Firstly, a request is sent from the video player to the ad server to retrieve the video ad.

2. VAST Inline Response

Next, the ad server receives the request and replies with an inline response containing the media file and requisite tracking URLs.

3. Tracking URLs Pinged

Finally, once the video has been played, the video player then fires the tracking pixels to begin recording impressions for the video in question.

What Is a Vast Tag?

A VAST Tag is designed to ' work exactly like a third-party JavaScript ad tag, except it's specifically for video.'

As already noted, VAST utilizes XML markup schema, and VAST Tags are the pieces of code used in this language that allows video players to understand detailed information about the ad, such as:

  • The length of the ad
  • The ad format (i.e., mp4 format for digital videos, flv format for flash videos)
  • The destination URL for audience clicks

Below is a complete example of a VAST Tag.

VAST Tags in XML example

A small section of a VAST Tag in XML, which contains information about the type of media file, will display as follows:

<MediaFile delivery= ‘‘progressive’’ width= ‘‘200’ height=’‘30’’ type= ‘‘video/x-flv’’ bitrate= ‘‘17’’ scalable= ‘‘false’’ maintainAspectRatio= ‘‘false’’>..</MediaFile>

In the above example, we see the video player developers are delivering an ad to the video player in .flv format.

A Brief History of VAST and Video Ads

As previously mentioned, VAST Tags were created by The Interactive Advertising Bureau(IAB). VAST 1.0 was released in 2008 and has been regularly updated ever since.

Here is a brief history of the ad serving template VAST journey:

  1. VAST 1.0 was released in 2008, supporting MP4, 3GP, and .MOV video formats. It had play/stop/pause functionality and basic linear event tracking.
  2. VAST 2.0 saw a move to support an increased number of video formats, including MP4, 3GP, .MOV, Flash, and JavaScript. Along with play/stop/pause functionality, VAST 2.0 offered quartile event and player tracking (linear, non-linear, and companion ads).
  3. On release, VAST 3.0 featured the above functionality and offered advertisers the ability to display skippable ads, OBA compliance, and improved error reporting.
  4. Released in June 2018, VAST 4.0 supports several tag options for ads, including separate video and interactive files, mezzanine files, server stitching, viewability, verification, advanced reporting, and closed captioning capabilities.

Key Elements in a Vast Tag

Some elements included in the tags will vary depending on the publisher's and advertiser's individual requirements from the video player.

However, there are three main elements in every tag.

1. Media File

All VAST Tags link to a media file that contains the advertiser's ad creative. Typically, this is a web link that directs to a URL that pulls up the video ad. However, in some cases, attributes will create a link to the ad server to retrieve the video ad.

2. Video Format

VAST Tags also define the format of the ad creative. The video format may be Flv, mp4, or GIF, for example.

3. Tracking

Tracking the performance of video ads is an integral part of the video advertising process. The VAST Tag will usually contain a link to a resource file included within the ad server. This link contains a tracking pixel that registers ad impressions and other important information so the advertiser can determine the video ad unit's effectiveness.

Aside from the above three components, publishers can include several other attributes in their tags. These advanced tag options include, but are not limited to:

  • The type of ad (i.e. pre-roll or mid-roll)
  • The length of the video ads
  • The dimensions of the ad

Benefits of Vast Tags

Since their introduction in 2008, the VAST Tag protocol has dramatically improved digital publishers' ability to monetize their websites through the display of video ads.

Some of the benefits of VAST Tags include:

  • Provides a streamlined language for communication between ad servers and video players
  • A reduction in ad playback and rendering errors
  • Empowers advertisers with increased control when creating and implementing video ads
  • Saves time and money

How to Create a Vast Tag

Creating a VAST Tag is a relatively simple protocol, particularly for digital publishers and developers.

There are three ways to create a VAST Tag, and it is really up to publishers to decide which option best suits their ad type:

  • Manually
  • Through an advertiser's Ad Server (such as Google Ad Manager)
  • By utilizing Third-Party Tools

1. Manually 

For publishers who have a pre-existing knowledge of XML and the concept of pre-defined parameters, manually creating a Video Ad Serving template tag should be a relatively straightforward process.

Below is a list of the pre-defined parameters required to create a VAST Tag manually.

List of Parameters to define when creating a VAST Tag

After defining the above parameters' values, advertisers can then use the content to create an XML.

While publishers may prefer to create VAST Tags manually, AdOps engineers will use the parameters to verify the VAST Ad Tag, so there is actually little benefit to creating the ad in this manner.

2. Create a VAST Tag in Google Ad Manager

While advertisers can use any VAST compatible ad server to create an ad tag, Google is by far the most popular for advertisers wishing to create video ad content.

To generate VAST Tags in Google Ad Manager, publishers will firstly need to ensure they have a dedicated Google Ad Manager account.

It is also important to note that when creating tags using this tool, publishers must ensure the URL they use begins with "HTTPS" or "HTTP". 

Creating a Vast Tag for video ads in Ad Manager involves the following steps:

  1. Sign into Google Ad Manager using Username and Password
  2. In the table of contents, click on Inventory >> Ad Units
  3. Locate the ad unit and click on Tags
  4. Fill out the option for each section- Tag type, Tag Option, and Tag Results, clicking continue after each step
  5. Click on Copy Tag

3. Create a VAST Tag with Third-Party Tools

A range of Third-Party tools in the market aside from Google can be used to create VAST Tags. However, publishers need to ensure that their video player supports all required specifications. This will prevent any unnecessary errors in the ad display.

How to Validate Vast Tags

As VAST Tags use XML as their markup language, there is always a chance that some VAST Tags may contain a bug. However, publishers can ensure a video ad is operational by utilizing a tag validator.

The most common validators on the market are:

1. IAB's VAST Tag Validator

Developers can use the IAB developed validator to validate and test their VAST Tags. You will need to register to access this.

2. Video Suite Inspector

Developed by Google developers, the Video Suite Inspector is recommended by Ad Manager to validate VAST Tags.

3. Vast Tag Tester

Developed by Springserve, the Vast Tag Tester is also a popular choice.

Validators work by implementing and testing the code. They contact the relevant URLs to ensure the video ads are working as expected.

Final Thoughts

While no technology is perfect, VAST has come a long way since its inception, and utilizing VAST Tags will ultimately maximize video ad performance across your web pages.

Need help getting started with VAST Tags? 

At Publift, we empower digital publishers to leverage the latest technologies for optimum performance and growth. Contact our friendly team to learn more today.

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