YouTube's New Anti-Ad Blocker Tactic: "Fake Buffering" Delays Videos by 10+ Seconds

Last week, some users had observed YouTube seemingly throttling video speeds server-side as a countermeasure against ad blockers. Once an ad blocker is activated, the video stream’s loading speed plummets, often to the point of unwatchability. YouTube then presents users with a playback issue warning, which, upon further inspection, suggests that the use of ad blockers may be impairing normal video playback.

Though initially speculative, developer @LOOPS has now published an analysis indicating that YouTube is indeed experimenting with a “fake buffering” technique. This method is currently being deployed via A/B testing to gather feedback from different user groups, meaning not all users will encounter the artificial delay.

Fake buffering is a deliberate latency mechanism developed by YouTube. When an ad blocker is detected—whether it’s a browser extension or a built-in feature—the platform artificially delays the initial loading of the video.

This lag is not due to the actual content failing to load; rather, it is a manufactured delay introduced through technical means. Notably, the buffering occurs only at the beginning of playback and typically mirrors about 80% of the original ad duration.

For example, if an ad was meant to be 15 seconds long, the resulting delay might be approximately 12 seconds. In cases where an unskippable 6-second and 15-second ad are combined, the delay may stretch to 16.8 seconds—an intentional deterrent targeting users who block advertisements.

YouTube employs its internal API and the GVS (Google Video Streaming) infrastructure to enforce fake buffering. When a user clicks on a video, YouTube’s backend provides a video stream link embedded with delay instructions, forcing the player to pause before beginning playback.

Strikingly, Google’s A/B testing is indifferent to ad-blocking status—everyone in the test group may experience the delay. However, for users who don’t block ads, the delay is negligible and barely perceptible. For those who do, it becomes significantly longer and detrimental to the viewing experience.

Importantly, rumors circulating online that YouTube artificially increases CPU usage to damage users’ hardware are completely unfounded. The fake buffering is a player-level instruction and requires no additional CPU load.

The technical community has identified partial workarounds to bypass fake buffering while continuing to block ads. By modifying specific parameters in the YouTube player, users can eliminate the artificial delay.

The key lies in setting the isInlinePlaybackNoAd parameter to true, a field found in YouTube’s internal API (InnerTube API). Technologists uncovered this attribute by analyzing YouTube’s front-end JavaScript and underlying protocols.

Specifically, ad blockers like uBlock Origin can insert custom filtering rules to dynamically alter outgoing JSON requests from the client, appending the isInlinePlaybackNoAd: true field to prevent ad loading and, by extension, fake buffering.

However, this method only applies to “hot navigation”—clicking from one video to another within the YouTube interface. If a user arrives at a specific video via an external link, the playback data is embedded server-side at page load and cannot be modified by the client.

In retaliation, YouTube has begun deploying a script-locking mechanism that sets certain global objects as non-writable, thereby preventing ad blockers from proxying and modifying request data. This script is typically injected at the top of the HTML head and executed as the page’s first element.

While Firefox users can circumvent this issue using HTML-based filters, those on Chromium-based browsers face limitations due to extension API constraints. As a result, the technical community continues to explore alternative methods of resistance.

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