Automatic content recognition (ACR)

Automatic content recognition works like a song-recognition app built into the TV. Software on the set takes compact fingerprints of the image or audio at short intervals and sends them to a server, which matches them against a library of programs and ads. Because the fingerprint comes from what is displayed, ACR can identify content from broadcast channels, streaming apps and devices plugged into the HDMI inputs, not only from the TV’s own apps. The resulting viewing log is a form of telemetry about the household rather than the device.

Manufacturers use ACR data for recommendations, audience measurement and targeted advertising, which makes it one of the clearest privacy trade-offs in the smart home. It is normally switched on through a consent screen during setup and can be switched off in the TV’s privacy settings, under names that differ by brand. Questions to ask are who receives the data, how long it is kept under the maker’s data retention policy, and whether turning it off deletes what was already collected. The smart home guide covers privacy across connected devices more broadly.

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