Adam Breeden/ZDNET
Follow ZDNET: Add us as a preferred source on Google.
It's been something of an open secret over the last decade or so that your TV and other devices monitor your streaming activity in order to serve you personalized ads or content suggestions.
Also: How to disable ACR on your TV - and why it makes such a big difference doing so
But did you know that most smart TVs also analyze things you watch on devices connected via HDMI? A modern smart TV is just as capable of mining a 20-year-old DVD for advertising data as it is your Netflix queue. Thankfully, we've found a few ways to help keep your TV-viewing experience as private as possible.
How HDMI content tracking works
A smart TV will use two methods to track your viewing habits through media played on HDMI-connected devices:
HDMI-CEC Metadata: This is a very technical term for an HDMI device's ID. When you connect a game console, Blu-Ray player, or other playback device, it sends "device ID" data to your TV, primarily to allow a single remote to control your TV and any connected devices. However, it does also track how long you use that device (ex, "Profile A used Input 1 [PlayStation 5] for X hours).
This is a very technical term for an HDMI device's ID. When you connect a game console, Blu-Ray player, or other playback device, it sends "device ID" data to your TV, primarily to allow a single remote to control your TV and any connected devices. However, it does also track how long you use that device (ex, "Profile A used Input 1 [PlayStation 5] for X hours). Automatic Content Recognition (ACR): This method feels much more "spy-like" given how much data it tracks. The TV will take tiny "fingerprint screenshots" of each pixel on the screen, regardless of the source, and then feed that data into an algorithm to identify exactly what movie, show, or video game you are playing on an HDMI-connected device.
"One of the most significant findings is that ACR tracking occurs even when the TV is used as a 'dumb' display," according to researchers at the University of California, Davis. This is very general data that companies refine with the next method.
... continue reading