I bought a 8 series Samsung TV on Tizen with Apple TV app.
I tried to stream videos from my mac using quicktime and apple TV app on my mac. Quicktime does nothing and apple TV app says "This video is in a format that can’t be streamed to this TV." on any videos i have, even those i made with an iPhone X (however it works by streaming it from the phone itself). Even when I made the "Apple TV version" via Apple TV app it still shows the same message on the converted video. All those videos can be played by the tv using the USB stick.
BTW screen mirroring from mac works