Dolby vision on Apple TV 4K blacking out

I should have made clear that I'm seeing the problem on the latest AppleTV 4K (2021), even with tvOS 15, although it may be somewhat better. The firmware in my C1 was just updated, and may have helped a bit but hasn't totally fixed the problem.

I did find that switching the AppleTV to 4K HDR from 4K Dolby Vision helped a bit.

Thanks for indicating that the problem isn't specific to LG devices!

I think we're talking about 2 different phenomena. I do have an 8K cable and don't experience drops. What I **do** experience is a 10-second or so delay soon after turning on the AppleTV, during which the screen blacks out (can happen after merely displaying the AppleTV app icons), then "Dolby Vision" appears in the upper right-hand corner, and then the regular TV image is back.

I think this happens only once after the AppleTV is turned on.

I have been having the same issue as everyone else here and I found my fix. When I connected my Lg C1 I also added a Lg SP2 sound bar with an optical able and atv 4K. I then switched out the optical cable for a hdmi cable as my sound bar has a hdmi arc port and that’s when my tv started flashing to a black screen and coming back with Dolby or HDR in the corner. Like everyone else I changed every cable and setting except the hdmi cable from the sound bar. I just switched my hdmi cable back to the optical cable and have not had a issue since. I’ve tested every stream app Netflix, sling, hbo, STARZ Disney Plus and Prime all without the black screen flashing.

I'm not sure what changed, but I had the same issue as well. Ironically, selecting 4k HDR output on the Apple TV corrected the problem. I was worried that this change would no longer allow Dolby Vision content to play in HDR, but my TV says it's displaying Dolby Vision even though the Apple TV doesn't have Dolby Vision selected. I'm assuming this is a bug and will be fixed. One would think the way to view Dolby Vision content would be to enable Dolby Vision.

Equipment: Apply TV 4k (new), LG 77C9, Marantz SR6014, HDMI 2.1 cables

I'm having the same issues with Dolby Vision constantly blacking out. It has nothing to do with LG in my case as I have a Sony Z series TV. I have also verified that Dolby Vision works perfectly fine when coming from alternate sources (Xbox Series X, PS5, FireTV Cube) which all play Dolby Vision flawlessly.

My Apple TV 4K is the 5th Gen. 32GB model and it is running the latest tvOS.

It is also worth noting that this issue has been occurring during the past 2 or 3 tvOS updates as I have been having this issue for the past couple of years off and on. I keep hoping for a fix.

I also considered upgrading to the newest Apple TV 4K model in hopes it was a hardware issue.

Any help would be much appreciated as it is very distracting and annoying to fiddle with constantly.

Hey there Troiano27,

Based on your post it sounds like you're having trouble watching content in Dolby Vision on the Apple TV 4K.

Does this seems to occur with different Dolby Vision supported shows and movies on the Apple TV 4K?

Knowing this can help isolate the issue to the content itself.

Does restarting the Apple TV help at all?

Restart Apple TV

If this impacts all of the Dolby Vision content on the Apple TV 4K you can check your settings and cables if need be. You should also make sure tvOS is fully updated. Take a look at all the steps listed below.

About 4K, HDR, and Dolby Vision on your Apple TV 4K

Cheers!

Unfortunately, none of the above recommendations helped out. To keep this somewhat clean I'll bullet point and use terms that are searchable

• Tried restart/resets on the three devices - lg cx, apple tv 4k 2nd gen, denon x3600h
• Tried the same tv settings with other devices connected to the same port on the receiver( avr ) and those work - xbox, roku ultra, PC desktop
• Tried apple tv 4k (atv) in DV, HDR, SDR, YCBCR, RGB High, Match content On/Off, Match Dynamic Range On/Off None of this fixed it
• Connected atv to LG CX directly on HDMI port 1 with same cable everything works fine

This is awfully frustrating not being able to have the atv on the receiver. Something similar happens with my MacBook pro but i wont muddy the thread. Same blanking behavior though

Correct, it isn't rigorous enough. The 4k cable might pass but you might be in a situation where it's choking at the traditional 18gbps cable and that's where the full bandwidth of the 48 comes into play.

• handshake
• colorspace
• audio
• chroma
• resolution
• cec

My strong suspicion is that any hiccup in the transmission of any of those will cause the handshake to stutter and drop signal.

Ideally, it would've stopped by lowering the resolution and sending less data to the tv but not sure the software is not checking to see what the display is capable of.

Trust me, i hate the idea of buying yet more cables but these were cheap amazonbasics 8k / 2.1 HDMI cables (just make sure it's 48gbps) 6ft.

Have been testing all day today and went from drops several drops an hour to no drops all day

edit: and i'm on the most recent update of tvos 15.1

@anniemcd59 glad to hear!!

@odysseus9021 ah yes we are talking about different issues. I was able to benefit from resolving that issue as well with the cables but this might be a YMMV situation. Not sure if you're connecting directly to the TV or not. If you are then good start with the 8k cable, if it's making a hop through a receiver just confirm both cables are 8k.

• Try connecting the ATV to a different HDMI port other than ARC (traditionally HDMI 2)

This is not the ATV 4K nor is it related to cables, etc.

The issue is with the LG C9 firmware. Around the time your problem started LG updated the firmware to version 05.10.04. Any DV capable device connected through an AVR, such as your Marantz, and then to the LG experiences the problem. I have the same exact issue.

LG is well aware of the problem and is testing/perhaps rolling out a fix already. It MAY be 05.10.15. Best bet is to wait for the update and use HDR as you are doing. I'm doing the same.

Here is a thread that has information in a number of posts. The user "HiFi4Vision" is credible.

https://www.avsforum.com/threads/official-2019-lg-c9-consolidated-info-faq-troubleshooting-firmware-more.3075344/page-80

Suggest you start with post #1583 and read thru.

This is the LG link (assuming you are in the US) where you can see what the current firmware is. You might want to consider turning off automatic updates. I wish I has not turned mine back on.

https://www.lg.com/us/support/product/lg-OLED65C9PUA.AUS

There is also discussion that your AVR might require an update. Oddly enough my Denon got an update a day or two after the initial occurrence. They didn't say what it was for. You may want to check for AVR updates.

Hope this helps. It's complex and difficult to tell what is creating the issue. I was lucky - the LG wanted to do an update - I let it - and immediately after I played a show that was in DV and got the blanking/blacking.

Version 05.10.25 has been released in South Korea. This likely corrects all the issues. See this post:

https://www.avsforum.com/threads/official-2019-lg-c9-consolidated-info-faq-troubleshooting-firmware-more.3075344/post-60948311

I have a Sony XBR65X900F, a Pioneer VSX-LX103 HT with Dolby atoms, Dolby Vision 4K 2.2 HCPT ACT pass through, with Monster high speed cables 2.2 ect. My 2018 ATV 4K with Dolby Vision shuts off and on constantly. I have updated to 15.01 and did several reboots. Along with shutting off matching and everything else recommended in the forums. Watching Disney+ UHD movie, All it did was cut out. So I switched over to ROKU Ultra. Nothing cut out. Sound and picture were great. Sooooo… what do I do now?

I am heavy into the Apple walled garden. I have even considered buying the 2021 4KATV. However, my 2019 4KAVT should still be working? I am at a loss. I have just “cut the cord” to go to total streaming. 🤷🏼‍♀️

I am on LG C8 as mentioned above. My issue happened only on Apple TV 4K and finally this problem was completely resolved after disabling the Dolby Atmos sound option, switched to surround sound. My visuals are still set to 4K Dolby Vision. Haven’t had a single issue in the last 2 weeks and I watch lots of shows.

Previous attempts of upgrading hsmi cable, TV firmware upgrades, switching to HDR content did not help. I think the problem is sound related. I use optical headset from Sennheiser which didn’t require Dolby atmos but the option was enabled for me in the menu in sound options.

So I think this is most likely a software bug on the Apple side and they need to patch it on their TVOS. Not hardware related. It's a confusing bug too, because it's a sound related bug that causes visual glitches and it leads people to look for solutions in unrelated areas. On top of the sporadic annoyances on a nightly basis since mid summer on my new Apple TV 4K, I also bought an expensive HDMI cable from Apple Store to just try to fix this out... Wish they would addressed this quickly in the summer..

I have a wireless Sennheiser headset, the base transmitter is connected optically to the LG C8 TV. Enable Dolby Atmos to replicate bug please. Happens on many shows on Netflix, Amazon Prime, Apple TV+ especially on the show "See", you can trigger it quickly multiple times per show..

@alexhus thanks for coming back to drop that comment from your last post in July. This did not work for me but what you did got me thinking (and so far it did work)

Everyone: it is and isn't the HDMI cables. - SOLVED

What might be happening is that 4k cable gets swapped for a 4k cable and bandwidth is still not met on the cable. I bought the amazonbasics 8K 48gbps cables. The 48gbps is the most important thing to focus.

If you're connecting directly to the tv then you only need one cable

If you're connecting the ATV to an AVR you need two cables - one from the atv to the avr / the other from the avr to the tv

Please report back and let me know if it worked. Figuring this out was so great (in my case now i can use my DIY ambilight set up)