There was another thread with a paywalled article, but here’s the actual study that found that smart TVs use “automatic content recognition” to build an ad profile for you based on what’s on your screen… including HDMI content streamed from a laptop, game console, etc. Yikes.
At a high level, ACR works by periodically capturing the content displayed on a TV’s screen and matching it against a content library to detect the content being viewed on the TV. It is essentially a Shazam-like technology for audio/video content on the smart TV [38]. ACR is implemented by all major smart TV manufacturers, including Samsung [9] and LG [55 ].
Our findings indicate that (1) ACR operates even when it is used as a “dumb” display via HDMI; (2) opt-out mecha- nisms stop ACR traffic; (3) ACR works differently in the UK as com- pared to the US.
So it seems like you’re opted-in by default, but you can stop ACR traffic by simply configuring six different options on Samsung, or eleven different options on LG.
Oh, and this doesn’t seem to happen when you’re using native streaming apps like Netflix or Disney+, because hey, they wouldn’t want to infringe on those companies’ rights by spying on them, right?
Lot of people saying they don’t give internet access to their TVs.
Fine, but that doesn’t work for cord-cutters who opted out of cable to go with streaming. And if you keep your TV away from internet but have a cable box, it will be doing all the tracking in this paper (and worse) then sending it to the cable provider.
So short of sticking with DVD/Bluray (unconnected) or over-the-air broadcast TV, there’s no way to stop from getting tracked.
The paper also lists domains where the data is being sent. You could always try blocking the destination addresses at the router level.
AFAICT, keeping the TV offline (i.e. not connected to any wifi) and plugging in a laptop/Chromecast/etc. via HDMI would eliminate both sides of the problem. You can still use streaming services on the laptop, but the TV would be unable to phone home.
There’s always the yar har option as well, which is also effectively implemented with a laptop.
