Smart TV Tracking: Turning ACR Off May Not Stop It, Study Finds

ExplainedUpdated 26 Oct 2026

Smart TV tracking is back in the spotlight after a Northeastern University study found that some TVs keep sending traffic to their viewing-recognition servers even after you switch the feature off. The short answer: on LG, Fire TV, Sony's Google TV and VIDAA sets the opt-out worked in the researchers' tests, but on Samsung and Vizio TVs it did not fully stop the traffic, and the only sure fix is to take the TV offline or block the tracking servers. If you have already cleaned up Google's new ad personalisation settings, your TV is the next device worth checking.

At a glance

What it is: Automatic content recognition (ACR): the TV fingerprints what is on screen and sends it to a server that identifies the show or advert
Who it's for: Anyone with an internet-connected TV, especially Samsung, Vizio and Roku owners
Cost: Free to switch off; an external streaming stick costs extra
Available in Saudi Arabia: Partly: the study tested US models only, and we could not confirm how Saudi-market firmware behaves

Key points

Researchers ran 5,943 automated experiments on 12 smart TVs from 10 brands, covering operating systems used on about 95% of US smart TVs.
The ACR opt-out fully worked on four systems: LG webOS, Google TV on Sony, VIDAA and Amazon Fire TV.
On Samsung Tizen and Vizio, traffic consistent with ACR continued after opting out, although the researchers could not read the encrypted data.

Why smart TV tracking is trending

The study, titled "Watching the Watchers: Privacy Analysis of US Smart TV Automatic Content Recognition", was published on 19 October and reported by Ars Technica two days later. Consumer sites followed, and the topic then spread on X. Using X's post-count tool, we counted about 57 posts on 21 October that paired "smart TV" or "Samsung TV" with words such as tracking, ACR or privacy. That jumped to 885 on 22 October and reached 1,473 on 25 October, and X's news panel ran a story on cheap smart TVs funding themselves with viewing data.

The reason it struck a nerve is simple. Most people assume a switch that says "off" means off. This study is one of the first large, repeatable tests of whether that is true for TVs, and for two of the biggest platforms the answer looks like "not quite".

How ACR works, in plain English

Automatic content recognition is software built into the TV's operating system. Every few moments it takes a tiny sample of what is playing, either a frame of video or a snippet of audio, turns it into a compact "fingerprint" and sends that over the internet. A server compares it with a huge library of shows, films and adverts, and works out exactly what you are watching. The researchers say that viewing history can then be used for targeted ads and shared with or sold to other companies.

What surprises most owners is how wide the net is. ACR does not care whether the picture comes from a built-in app, an aerial, a games console or a cable box plugged into HDMI. In the study, broadcast TV received through an antenna was tracked on every operating system the team could analyse, while Netflix and YouTube were not tracked on any of them. The team also found that Samsung's system recognises content by picture, while LG's relies on sound.

What the study found, brand by brand

The team built an automated "living room" in which control scripts played the same content on every TV, through antenna, HDMI, apps and screen mirroring. Each scenario ran 30 times with tracking on and 30 times after opting out in the TV's own settings, while all network traffic was recorded.

Samsung (Tizen)

Tizen is the biggest smart TV system in the US, with about 34% of the market according to the study. After opting out, traffic consistent with ACR still appeared in all 30 runs of Samsung's own streaming service, 41 of 60 antenna runs and 18 of 30 HDMI runs. Ars Technica said it had asked Samsung for an explanation.

Vizio

Vizio's result was the starkest. Traffic to the endpoint the researchers linked to ACR continued in every opted-out scenario with no drop at all, and with tracking switched on the TV sent ACR-pattern traffic even while it sat idle on its home screen. Separately, Vizio's free WatchFree+ service put programme names into unencrypted web lookups, which anyone on the network path could read.

Roku, VIDAA and the brands that passed

Roku's opt-out covers antenna viewing but not Roku's own streaming service, something Roku discloses in its terms. VIDAA's opt-out worked, yet its ACR messages were sent unencrypted, and the server behind them exposed more than 57 million detection results before VIDAA added a login after being told. LG webOS, Google TV on Sony and Fire TV were the clean passes.

Our analysis: what this does and does not prove

It is important to be precise. Because the traffic was encrypted, the researchers could not see what Samsung and Vizio actually sent. They describe the continued traffic as "suspicious" and consistent with tracking, not as proof. Lead author Ilgar Mammadov told Ars Technica that even if it were a bug, the outcome for users is the same: their choice is not reflected in what the TV does.

History makes the concern hard to dismiss. In 2017 Vizio paid $2.2 million to settle US Federal Trade Commission charges that it collected viewing data without consent, and in 2025 the Texas attorney general sued Samsung, LG, Sony, Hisense and TCL over ACR. Ars reports that Samsung settled by agreeing to explain ACR more clearly. Our view: the business model of cheap TVs now leans on advertising, so owners should treat privacy settings as a starting point, not a guarantee.

How to turn off smart TV tracking: step by step

Samsung: press Home, open Settings, then All Settings, General & Privacy, Terms & Privacy (called Privacy Choices on some models). Turn off Viewing Information Services and Interest-Based Advertising.
LG: open Settings, All Settings, General, System, Additional Settings and turn off Live Plus, LG's name for ACR. Then switch on Limit Ad Tracking in the advertising settings.
Other brands: look for wording such as "viewing information", "viewing data" or "smart interactivity" in the privacy menu and turn it off. Menu names change by model year.
For certainty: disconnect the TV from Wi-Fi and Ethernet and watch through an external streaming device. A TV with no connection has nowhere to send fingerprints.
Advanced: if you run a network-wide blocker such as Pi-hole or AdGuard Home, add the researchers' published ACR blocklist. In their lab tests, blocking those servers did not break viewing.

Pros and cons

Pros of switching ACR off

Less viewing data shared for advertising
On LG, Fire TV, Sony and VIDAA sets the switch worked in testing
No effect on picture quality or normal streaming

Cons and limits

On Samsung and Vizio the setting may not stop all traffic
You lose "recommended for you" features
Taking the TV offline means relying on a separate streaming box

Privacy and safety tips

Treat the TV like any other connected device. Turn off voice recognition you do not use, keep the firmware updated, and consider putting smart home gadgets on a separate guest network so they cannot see your phones and laptops. If you suspect a device has been tampered with, our guide to the signs your phone is hacked covers the same habits that protect every screen in the house.

How we checked this

We read the research team's project page and the Ars Technica and Techlicious reports on 26 October 2026, took menu paths from Consumer Reports and Tom's Guide, and measured interest with X's post-count tool. We did not test a TV ourselves, and results apply to the US models and firmware the researchers used.

Bottom line

If you own an LG, Sony Google TV or Fire TV set, switching ACR off in settings is worth the two minutes and appears to work. If you own a Samsung or Vizio, switch it off anyway, but if privacy really matters, disconnect the TV from the internet or block its tracking servers at the router.

FAQ

Is my smart TV listening to my conversations?

The study measured content recognition of whatever is playing on screen; it did not test microphones. LG's system identified programmes by their soundtrack, and Samsung's by the picture.

Does turning off ACR affect Netflix or YouTube?

No. Normal streaming still works, and in the study neither Netflix nor YouTube was tracked by ACR on any TV.

Does this apply to TVs sold in Saudi Arabia?

The tests used US models. Menus are similar worldwide, but we could not confirm how Saudi-market firmware behaves, so switching ACR off is still sensible.

Is a streaming stick safer?

Fire TV software passed the opt-out test, but the researchers tested TVs running it, not the sticks themselves.

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