Apple TV 4K White Flashes

When I installed iOS 11.2 on Apple TV and turned on options "Match Dynamic Range" and "Match Frame Rate" (https://9to5mac.com/2017/12/04/tvos-11-2/) the flashes became history. They are gone now.

I also have this problem on an LG OLED55C7P. I talked to Apple and was given this workaround. In Settings, in Video and Audio, try turning Dolby Vision off and use 4K HDR instead. It seems to work. I only hope that this problem will eventually be resolved. Generally, Dolby Vision is considered better than HDR.

This could be an issue with the handshaking between the source, the AVR, and the display device. I have the same problem, when I by-passed the AVR (any brand), the problem went away.

Hope this helps

Ed

For my Samsung TV, I have one HDMI input that is 'UHD' compliant. Apple TV works in UHD on the other HDMI ports - but with the flashes and black out issues... I swapped Apple TV 4K to this port and all seems OK now. The only problem is that my UHD Blue-Ray is now plugged into a non-UHD HDMI port.

So it may be time to upgrade to a TV that has more than one UHD HDMI port.

I have a Sony KD-55xe9005 directly connected to Apple TV 4k with the recommended HDMI cable from Belkin (48 gb) I and used to see the white flashes when setting video quality to HDR. The flashes appears to be gone after changing the video settings to ”Match framerate” and ”Match dynamic range” as mentioned earlier in this thread.

Hey Fred, can you check to see if the useable port is HDCP2.2a compatible? And the other ones are not?

if should say on the port itself or the manual.

I have a Sony XBR 4K as well. As I recall, to display UHD, I had to go into the manual and change the ports to UHD 60Hz 4.4.4. Give it a go.

Apple told me that a workaround for this problem is to turn Dolby Vision off. I hope Apple will fix it soon.

Yes, the frame flashing stopped when I switched the Apple TV 4K from Dolby Vision mode to HDR mode. But that's a lousy workaround because it deprives us of a feature we paid for. Hoping for a fix soon.

Update: After switching my HDMI cable to input 2 on the LG OLED tv, the flickering/flashing seems to have stopped in Dolby Vision mode. (Even though HDMI 1 input on the LG tv purportedly supports Dolby Vision HDR.)

It might be a handshaking issue... however i have switched from 4K HDR to 4K SDR resolution and the problem is now gone, i am still running through my AVR.

So I believe it is a problem Apple has to look into because i would really like to use HDR.

Doing a full restore/reset seems to have cleared up the issue for now... but we’ll see if it lasts. Seems like the issue returns for most people. Still think it’s a TV OS issue (not just a 4k apple tv issue) with 4k TVs.

Scott, I have found that most receivers are the problem of passing 4K to the display. Try by-passing the receiver and go directly from the ATV4K to the display.

Also check your cables are 4K compatible.

hope this helps,

Ed