https://www.ftc.gov/business-guidance/blog/2017/02/what-vizi...

"Starting in 2014, Vizio made TVs that automatically tracked what consumers were watching and transmitted that data back to its servers. Vizio even retrofitted older models by installing its tracking software remotely. All of this, the FTC and AG allege, was done without clearly telling consumers or getting their consent.

...

"Vizio collected a selection of pixels on the screen that it matched to a database of TV, movie, and commercial content

https://arxiv.org/pdf/2409.06203 shows LG and Samsung doing something similar