I'm facing this long time issue with my QN49Q60RAGXZD Smart TV.
The issue: The TV works fine in all functions but I can't stream through AirPlay directly from those specific apps: TV.app and QuickTime Player.app.
When trying to stream from QuickTime.app the app just freezes and no video is shown on the TV, when trying from TV.app no video is shown on the TV and this message is displayed on my macOS:
"This video is in a format that can't be streamed to this TV."
What works: Screen mirrorring and "use as separate screen" from macOS works fine (sometimes laggy), screen mirrorring and Music.app stream also works fine (both from iPad and iPhone). Videos streamed directly from Apple TV+ (through TV.app also works).
What I checked:
My devices are fully updated (macOS Catalina 10.15.4, iOS/iPadOS 13.4.1);
I've tried LOTS OF mp4/m4v variants encoded by MANY different softwares - DIDN'T WORK;
Tried stream camera videos (recorded a video, transferred to my MacBook (MOV file) then opened in both QuickTime.app and TV.app) - DIDN'T WORK;
Tried factory reset the TV - DIDN'T WORK;
I just don't know what else to do. I purchased this TV ONLY because this function (since I don't watch TV or use Netflix and others).