How to Enable Prebid Video Ads with Google Ad Manager: A Practical Guide for Publishers
Video advertising continues to drive a significant share of digital revenue for publishers, but making header bidding work smoothly for video placements—especially with Google Ad Manager (GAM)—can be complex. Publishers eager to capture high CPMs from video demand need reliable, tested workflows that balance yield, user experience, and operational clarity.
This guide demystifies what’s required to show Prebid-powered instream video ads through GAM. We’ll walk you through setup, custom price buckets, caching considerations, and operational nuances. Whether you’re just starting or fine-tuning an existing integration, this article aims to make your video ad stack more robust and maximally monetized.
Setting Up the Prebid Video Ad Unit and Required Modules
Before you can show header bidding video ads through GAM, you must prepare both your Prebid.js library and your ad server setup. This foundation is essential for robust video monetization.
Building Prebid.js for Video
Compile your Prebid.js bundle with a video-enabled bidder (such as AppNexus/Xandr) and add the dfpAdServerVideo module for GAM support. This step ensures Prebid.js can handle video-specific bid flows and communicate with Google Ad Manager properly.
Proper Google Ad Manager Line Item Configuration
Your ad operations team needs to set up dedicated video line items and creatives within GAM. These line items should match the targeting structure Prebid will signal, allowing for correct delivery of winning pre-roll or mid-roll ads.
Configuring the Video Ad Unit and Price Granularity
Accurate ad unit configuration directly influences which bids can participate in your auctions and what CPMs are eligible. Missteps here can lead to missed revenue or failed ad calls.
Key Ad Unit Parameters for Video
Define instream context, specify player size, video MIME types, accepted protocols, and enable skippable ads if needed. Include the correct placement ID from your bidder partner. Precise settings ensure compatibility and maximize fill.
Custom Price Buckets for High Video CPMs
Prebid.js limits CPMs by default (often at $20). Large video campaigns can exceed this, so use the setConfig({priceGranularity: …}) API to define custom price buckets. Without this, high-value bids may be truncated or dropped, limiting revenue.
Bid Request Flow, Video Caching, and URL Generation
Initiating the bidding process for video is more intricate than banner implementations. Video players require a URL to VAST XML, which often means caching responses and constructing specialized ad server requests.
Overview of the Bid Request Process
Add your video ad unit to the Prebid queue, initiate bid requests, and handle responses within a callback. Within your bidsBackHandler, use pbjs.adServers.dfp.buildVideoUrl to craft the final ad tag for GAM.
Role and Pitfalls of Prebid Cache
Many video players expect a URI that resolves to VAST XML. Some bidders supply a direct VAST URL, but others return only VAST XML, requiring Prebid to cache the response. Always configure pbjs.setConfig({cache: {url: …}}), or risk bids being dropped. Be mindful: if Prebid Cache is missing, and only a VAST XML is returned, valid bids can be lost—directly impacting yield.
Triggering Video Playback and Managing Multi-Ad Scenarios
Once you have a final video ad URL, it’s time to load this into your player (e.g., Video.js). However, video differs from display in that winning bid tracking is not always automatic.
Triggering the Video Player
With your constructed video URL, configure the player (using plugins like videojs-vast-vpaid) to load the ad via the provided VAST URL. Confirm autoplay and muted states as necessary for user experience compliance.
Managing Multiple Video Ads Per Page
Unlike banners, Prebid.js does not auto-flag a video bid as consumed after playback. On pages with multiple video placements, explicitly call pbjs.markWinningBidAsUsed to avoid serving the same ad multiple times—a common mistake that can lead to reporting inaccuracies and poor advertiser relationships.
What this means for publishers
Getting Prebid video to work seamlessly with GAM requires careful coordination between development and ad ops. Proper configuration ensures you capture every eligible bid, prevent technical failures, and protect both revenue and user experience. Video brings higher CPMs, but also stricter technical demands than display—mistakes can cascade into measurable revenue loss or ad serving issues. For publishers aiming to scale programmatic video, mastering these flows is essential to maximize inventory value and control.
Practical takeaway
For a successful Prebid video integration with Google Ad Manager, publishers should collaborate early with both engineering and ad ops: build Prebid.js with the correct video modules, define precise ad units, set up appropriate price buckets, and ensure the GAM line items match the signals Prebid sends. Don’t overlook the critical setup of Prebid Cache—especially when working with bidders who do not provide direct VAST URLs.
Test your implementation across browsers and with multiple video placements per page. Always use pbjs.markWinningBidAsUsed for multi-ad scenarios. With a systematic approach, publishers can unlock new revenue streams from video demand partners, reduce operational headaches, and stay competitive in today’s high-stakes digital video landscape.
