Samsung Q90R with AppleTV 4K blinks, disconnects after a while

[psychotoddler]

I’ve been searching for threads on this but its hard to describe so I never seem to find the right match. I have 14 month old Samsung Q90R 65” connected to a Samsung Q80R soundbar. To enable Dolby Atmos I have an AppleTV 4K connected through the sound bar with a pass through back to the TV. All cables are rated for 4K ultraHDR (Cable from Apple to sound bar and from sound bar to breakout box from TV. AND

Everthing works great for a while, great picture, great sound, but after about 45 minutes the TV “blinks”—picture goes black, sound plays, and after a second, picture comes back. I can’t tell if the resolution changes. Usually it will play for a while and then recur. Then it blinks out for longer and I will lose sound. Then I get the ”spinning dots” reconnect sign and it reconnects. Very soon it just repeats and is unwatchable. The only thing that fixes it is holding down the power on the remote to the TV until the TV restarts (samsung QLED symbol) and then I can watch for a while.

To some degree this went on since I got the TV but was usually rare and I’d only get the picture blink and no intervention. Lately it‘s more often and at least once an hour. Last few days it’s increasingly more frequent.

I’ve unplugged and replugged all the cables.

It does NOT seem to happen when watching apps on the TV itself, so it must have something to do with the AppleTV, the soundbar, or the connections.

Not sure why it’s becoming more and more frequent.

 

[next010]

What level of chroma subsampling is the ATV set on 444 or 420 ?

If its on 444 select 420 and see if that stabilizes it.

Also manually set the output to 4K 60hz SDR and turn on match range, refresh rate so it switches to 24Hz for HDR output on movies and such.

 

[psychotoddler]

Will try but I should mention that it happens with non HDR content like Babylon 5 on HBOMax.

 

[chopples]

Will try but I should mention that it happens with non HDR content like Babylon 5 on HBOMax.

Hi mate

the Apple TV doesn't use chroma 4:4:4 for HDR it uses 4:2:2 (and cannot be changed) SDR uses either chroma 4:4:4 or 4:2:0

It does sound like a HDMI lead issue tbh, as @next010 try chroma 4:2:0 and make sure frame rate matching is enabled. This will reduce the bandwidth going through the cable

I have the n850 soundbar and a while ago I started having issues with my ATV4K and signal blanking. Over time the hdmi port on the bar became somewhat loose, I think this is because I used a regular hdmi cable and due to the ports being on a right angle caused some stress on the port. I resolved it by slotting a razer blade in and bending the port back into shape. the q80r bar is the same in this regard so it may also be worth checking the hdmi port isn't loose.

 

[psychotoddler]

What level of chroma subsampling is the ATV set on 444 or 420 ?

If its on 444 select 420 and see if that stabilizes it.

Also manually set the output to 4K 60hz SDR and turn on match range, refresh rate so it switches to 24Hz for HDR output on movies and such.

Will setting output to sdr prevent me from watching in HDR or will it switch when appropriate?

 

[psychotoddler]

Changing chroma to 4:2:0 made it happen much less frequently and less severely so I think it’s an HDMI bandwidth issue. Can someone recommend good specs for ARC and HDR through the sound bar? I see lot of confusing equipment out there. Is 18gb enough?