YouTube Experiments with Embedding Ads Directly Into Video Streams
YouTube developers are experimenting with embedding ads directly into the video stream, making it harder for ad blockers to filter them out. This change was first noticed by the creators of the open-source browser extension SponsorBlock, which collects information about which parts of a video contain sponsored content so users can skip them.
The SponsorBlock team warned that server-side ad insertion disrupts the extension’s functionality, and they are already working on a solution. Additionally, embedding ads into the video stream affects the effectiveness of other ad blockers that people use on YouTube.
How YouTube Ads Work Now
Currently, YouTube uses client-side ad insertion, where JavaScript scripts and the video player on the user’s device load and display ads. This means the video stream and ads are separate, and the player is programmed to pause the content and play ads at specific points.
Most ad blockers disable YouTube ads by blocking the JavaScript scripts used to insert ads into the video stream. SponsorBlock works a bit differently: it uses crowdsourcing to gather information about various video segments and allows users to skip sponsored integrations.
What’s Changing with Server-Side Ad Insertion
Server-side ad insertion allows ads to be embedded directly into the video stream before the content is delivered to the viewer. As a result, users receive a continuous stream with ads already integrated.
SponsorBlock explains that YouTube streams videos using a series of small segments that are “stitched” together to create a continuous video stream. The playback order of these segments is determined by a manifest file, and when a user opens a video, the YouTube server sends them a playlist that includes both content and ad segments.
This approach complicates SponsorBlock’s work because it shifts the timestamps for sponsored content, and the amount of shift depends on the length of the ads. It also creates challenges for other ad blockers, which have a harder time detecting ads that are part of the video stream (as opposed to easily detectable client-side injections).
The SponsorBlock developers say that, for now, they have to block reports from browsers where server-side ad insertion is happening to prevent data corruption. However, if YouTube moves to server-side ad insertion on a larger scale, this approach will become ineffective.
In the future, the tool may be able to calculate ad durations using various metadata and YouTube’s user interface elements, but the system isn’t ready for that yet.
Future of Ad Blocking on YouTube
As for other ad blocker developers, over time they may develop more sophisticated detection algorithms, use metadata analysis, and advanced pattern recognition to identify abrupt changes in audio and video that could indicate the presence of ads.
Journalists from Bleeping Computer received the following comment from Google representatives regarding the situation:
“YouTube is working to improve the performance and reliability of both organic and ad video content. This update may result in suboptimal viewing experiences for users of ad blockers. Ad blockers violate YouTube’s Terms of Service, and we have long encouraged users to support their favorite creators by allowing ads on YouTube or trying YouTube Premium for an ad-free experience.”
It’s worth noting that Google gave a nearly identical vague comment to journalists at the end of May 2024, when ad blocker users discovered that, in some cases, YouTube videos would automatically skip to the end or have their audio muted, making it impossible to watch the videos.