Does Turning Off TV Tracking Work? New Study Says Not Always

Turning off smart TV ACR tracking may not stop some televisions from sending data that looks like tracking, according to a new study from researchers at Northeastern University in Boston. The paper, published Oct. 19, 2026, found that Samsung and Vizio TVs kept sending traffic consistent with automatic content recognition, or ACR, to their makers’ servers after owners opted out.

ACR works a bit like Shazam for your screen. The TV captures snippets of what is playing, either images or audio, and matches them against a database so companies can measure viewing and target ads. The study, “Watching the Watchers: Privacy Analysis of U.S. Smart TV Automatic Content Recognition,” drew wide coverage from Ars Technica and SamMobile this week.

What the Northeastern Researchers Tested

The team examined 12 smart TVs from 10 manufacturers: Amazon, Hisense, LG, Roku, Samsung, Sony, Supersonic, TCL, Vizio and Westinghouse. Those sets run eight different TV operating systems that, according to lead author Ilgar Mammadov, a research assistant at Northeastern, together cover about 95% of the operating systems used on U.S. smart TVs.

The researchers ran 5,943 controlled experiments, Ars Technica reported. They played content through several inputs, including built-in streaming apps, an over-the-air antenna feed simulated with a radio frequency modulator, HDMI from an external device, and third-party apps, both with ACR turned on and with it turned off. They captured each TV’s network traffic using the Mon(IoT)r and SPHERE research infrastructure and identified which internet address on each platform receives ACR data.

For Samsung’s Tizen system, that endpoint was acr-us-prd.samsungcloud.tv. For LG’s webOS it was a server run by Alphonso, the ACR company LG acquired. For Sony’s Google TV set, the researchers traced a candidate endpoint to Samba TV.

Samsung and Vizio Results After Opt-Out

With ACR switched off, Samsung TVs still sent traffic consistent with ACR in:

30 of 30 tests using Samsung’s own streaming service
41 of 60 antenna tests with moving video
18 of 30 HDMI tests
6 of 30 tests in the Tubi app

On Vizio’s operating system, the researchers said a content-linked endpoint hosted on Amazon Kinesis kept receiving traffic in 100% of opted-out scenarios, including when the TV was idle. “The opt-out setting has no observable effect on the traffic sent to this endpoint,” the paper says.

Roku TVs also kept sending ACR-like traffic, but only while using The Roku Channel, which Roku discloses in its terms. Opt-outs appeared to work on LG, Sony, Amazon Fire TV and Hisense’s VIDAA sets in the researchers’ measurements.

There is an important caveat. The traffic was encrypted, so the researchers could not see what it contained. “These behaviors indicate potential privacy violations; however, we cannot know for certain without access to payload content,” the report says. Mammadov told Ars Technica that a bug or data that is sent and then discarded are possible explanations, but that discarding it would be an inefficient way to honor an opt-out. Ars said it had asked Samsung and Vizio for comment.

Why It Matters: Past Settlements and Market Share

Samsung accounts for about 34% of U.S. smart TVs, SamMobile reported, so the findings touch millions of living rooms. Texas Attorney General Ken Paxton sued Samsung, Hisense, LG, Sony and TCL over ACR data collection, and Samsung settled by agreeing to collect ACR data only with informed consent, according to SamMobile and Ars Technica.

Vizio has faced this before. In 2017, the Federal Trade Commission said Vizio used ACR to collect viewing data without consent, and the company paid $2.2 million to settle.

How to Limit Smart TV Tracking

The researchers suggest a few steps for owners:

Keep ACR turned off in settings. On several platforms the opt-out worked in testing.
Disconnect the TV from Wi-Fi and use an external streaming device that does not perform ACR.
Use the block list of ACR domains and addresses the team published on its project site, which can be added to a home router or network filter without affecting picture quality.

The team also asks manufacturers to list every input ACR watches, such as antenna, HDMI, apps and screen mirroring, in their privacy policies, and to authenticate and encrypt all ACR traffic.

Questions about what devices share in the background keep coming up. This week Spotify started requiring a QR code check for Family plan members, and our guide to what’s leaving Netflix in November 2026 covers what TV viewers lose next month.

Sources

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Smart TV ACR Tracking: Northeastern Study Finds Samsung, Vizio Data After Opt-Out