In my experience debugging Heavy Ads

I want to start by saying, I went through the pain of debugging a "Heavy Ad" once and let me tell you, it was not fun or straight forward. Chances are you're here because you're facing the same issue.
Trying to workout why your ad is being blocked by Google Chrome's "Heavy Ad Intervention" can be a daunting task. But don't worry, I'm here to help you navigate through this challenge, well, hopefully - let me explain.

Finding the fault in your ad that is causing it to be classified as a Heavy Ad can be a tedious process. Let's say you have loaded your ad in browser for testing, now re-loading will probably not trigger the Heavy Ad Intervention again or will randomlly due to browser caching. So you have to clear your cache or use an incognito window to test again. This can make the debugging process slow and frustrating. So understanding common causes and knowing what your ad format and what its doing in the background might help you narrow down the issue faster. This will depend on your use case, but there are some common pitfalls that you can look out for.
"Question for you.." Are you here because of a video display ad? Then you might be in luck, because video ads are one of the most common culprits for being classified as Heavy Ads and are often easier to fix and optimize.

Start by answering these questions to help you narrow down the issue:

Is you total ad size over 4MB? How can you check this?
Use the Network panel in Chrome DevTools to see the total size of all resources loaded by your ad. Its the panel that looks like this 0.3 kB / 7,065 kB resources at the bottom of the Network tab.
If your ad size is over 4MB, find the largest resources and consider optimizing them. My guess is its your video file?? try to keep this to around 1-2MB if possible.

Is your ad a video ad? If so, what is the resolution and bitrate of the video?
Best practice for video display ads is to use 360p or under, this depends on the ad size of course.
Mp4 format using H.264 codec is widely supported and efficient for web delivery. Using Dash or HLS streaming formats are not recommended for display ads due to the high number of requests they introduce.
Make sure your video is properly compressed and encoded for web use, I,e., encoding your video with the Moov Atom at the start of the file for faster playback.
Bitrate should be optimized for web delivery, generally between 500kbps to 3000kbps for 360p video.

How long is the video duration? Is it longer than 15 - 30 seconds?
Video longer than 30 seconds will most likely be a large file size, consider trimming the video or using a shorter clip if possible. Google recommends keeping video ads to 15 seconds but I haven't had any issues with 30 second ads personally.

Hopefully by answering these questions, you can start to identify potential areas of concern and focus your debugging efforts more effectively from here.

Continue reading below for a more detailed explanation of Heavy Ad Intervention and how to fix it.

---

Understanding Heavy Ad Intervention in Google Chrome

Heavy Ad Intervention is a mechanism implemented by Google Chrome to protect users from ads that consume excessive system resources. When an ad is classified as "heavy," Chrome may block it from loading, resulting in a blank space where the ad would normally appear. This can be frustrating for advertisers and publishers, as it can lead to lost revenue and a poor user experience.

What is Heavy Ad Intervention?

Heavy Ad Intervention (HAI) is a feature implemented by Google Chrome to deal with ads that consume an excessive amount of system resources. These ads, often referred to as "heavy ads," can cause sluggish performance and consume a significant amount of network data, leading to a poor user experience.

Characteristics of Heavy Ads

Google Chrome classifies an ad as "heavy" if it meets any of the following conditions:

• Uses the main thread for more than 60 seconds in total.
• Uses the main thread for more than 15 seconds in any 30-second window.
• Uses more than 4MB of network bandwidth to load.

Why Does Heavy Ad Intervention Happen?

Heavy Ad Intervention occurs when Google Chrome detects an ad using excessive system resources. This feature is designed to protect users from ads that can drain battery life, consume excessive data, and slow down the browsing experience.

Factors That Contribute to Heavy Ads

Several factors can contribute to an ad being classified as "heavy." These include:

• High-resolution images or video content.
• Excessive or inefficient JavaScript.
• Bloated or poorly optimized ad code.
• Network latency or slow server response times.

How to Fix Heavy Ad Intervention Issues in Google Chrome

Fixing Heavy Ad Intervention issues involves identifying the elements of your ad that are consuming excessive resources and optimizing them. The following are steps you can take to resolve these issues:

Step 1: Identify the Problem

The first step in fixing a heavy ad is identifying the problem. Chrome's Developer Tools can be instrumental in this process. The Performance panel can help you identify resource-hungry elements, and the Network panel can help you see which resources are consuming the most bandwidth.

Step 2: Optimize Images and Videos

High-resolution images and videos can consume a significant amount of bandwidth. Compressing these elements without compromising quality can reduce their impact on system resources.

Step 3: Optimize JavaScript

JavaScript can significantly impact performance. Ensure your JavaScript code is efficient and doesn't block the main thread for extended periods.

Step 4: Minimize and Optimize Ad Code

Bloated or poorly optimized ad code can also contribute to heavy ads. Minimize and optimize your ad code to reduce its impact on system resources.

Best Practices to Avoid Heavy Ad Intervention

Here are some best practices you can adopt to avoid encountering heavy ad intervention issues in the future:

Keep Your Ad Lightweight

One of the simplest ways to avoid heavy ad intervention is to keep your ad lightweight. This means using optimized images and videos, efficient JavaScript, and minimal ad code.

Monitor Ad Performance

Regularly monitoring your ad's performance can help you identify potential issues before they become a problem. Tools like Google's Lighthouse can provide insights into your ad's performance and offer suggestions for improvement. I use this tool often to audit my ads. Lighthouse Metrics.

Test in Multiple Environments

Testing your ad in various environments, such as different devices and network conditions, can help you identify potential performance issues.

Future Trends in Ad Tech

As technology advances and user expectations evolve, the ad tech industry will continue to change. One expected trend is a continued emphasis on user experience, including the optimization of ads to avoid heavy ad intervention. Another trend is the increased use of AI and machine learning in ad optimization, which could help advertisers automatically optimize their ads for best performance.

Conclusion

Heavy Ad Intervention in Google Chrome can significantly impact your online ads' performance. However, by understanding why it happens and how to fix it, you can ensure your ads remain effective and deliver a positive user experience. By adopting best practices and staying aware of future trends, you can stay ahead of the curve and ensure your ads continue to perform well in an ever-evolving digital landscape.