YouTube is experimenting with server-side ad injection, where ads are added directly into the video stream. This approach disrupts ad blocker tools like SponsorBlock, a crowdsourced extension designed to skip sponsored segments, by offsetting all timestamps with ad times. The developer of SponsorBlock has set up a server to reject submissions from browsers experiencing this issue to prevent incorrect data entries.
Server-side ad injection makes ads indistinguishable from the video, countering traditional ad blockers that intercept ads delivered separately. This method is part of YouTube's ongoing efforts to combat ad-blocking tools, including targeting third-party clients popular on mobile devices. Users are encouraged to subscribe to YouTube Premium as an alternative.
Currently, this feature is in the testing phase and not widely implemented. Some users have already encountered the issue, but YouTube has not provided detailed information on the technical changes made to its ad-serving infrastructure.