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SnippetySnip

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Original poster
Jan 10, 2022
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I have the latest gen 64Gb ATV 4K box hooked up directly to my Panasonic GX800 TV which is Dolby Vision certified. I use a certified HDMI cable which passes all the A/V tests and everything works really well, except for Dolby Vision content.
All Apple TV+, Netflix and Disney+ 4K content in Dolby Vision suffer from incredible black crush, with lots of near-black flashing, posterisation and visible artefacting, particularly on dark scenes. If I play the same content via the TV's apps with exactly the same Dolby Vision picture settings, it plays back flawlessly in Dolby Vision and looks much better than via the ATV. What am I doing wrong?
I have tried tweaking every setting I can find on both the TV and the ATV 4K box but can't find a way to improve things. Does anyone have any suggestions or do I have a faulty box? I can play Dolby Vision content from other sources perfectly fine on the TV - I have a 4K Firestick which works fine, and a 4K BluRay player which also exhibits none of the problems with Dolby Vision encoded discs.

My ATV settings are:
Format: 4K SDR
HDMI Output: YCbCr
Chroma: 4:4:4
Match Content: Range & Frame Rate

Everything switches properly in terms of frame rate and dynamic range. SDR & HDR10 content looks great, it's just Dolby Vision that gives me these issues.
Any suggestions much appreciated.
 
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w5jck

macrumors 65816
Nov 9, 2013
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I'm not sure about your specific issue, but my Sony Bravia is connected to my ATV 4K 2017 and a Fire TV Cube 2nd gen plus has AndroidTV 9.x apps, and DV looks the same on all of them. Maybe you have either a bad HDMI cable connecting the ATV 4K or one that is not designed for the proper bandwidths required.

I think my ATV 4K settings are similar to yours but I’m not around the TV to double check. I do have Format set to 4K HDR and Match set to Range and Frame Rate. I can't remember what HDMI Output and Chroma are set to. Regardless, your settings look fine. It could also be a TV setting that is causing the issue. Also, verify that the specific HDMI port on your TV that is used to connect to the ATV 4K is DV capable.

Also, is the ATV 4K connected to a standard HDMI port on the TV or is it connected to the HDMI-CEC port. It shouldn't matter, but just for the sake of analyzing the issue...
 
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SnippetySnip

macrumors newbie
Original poster
Jan 10, 2022
22
3
I'm not sure about your specific issue, but my Sony Bravia is connected to my ATV 4K 2017 and a Fire TV Cube 2nd gen plus has AndroidTV 9.x apps, and DV looks the same on all of them. Maybe you have either a bad HDMI cable connecting the ATV 4K or one that is not designed for the proper bandwidths required.

I think my ATV 4K settings are similar to yours but I’m not around the TV to double check. I do have Format set to 4K HDR and Match set to Range and Frame Rate. I can't remember what HDMI Output and Chroma are set to. Regardless, your settings look fine. It could also be a TV setting that is causing the issue. Also, verify that the specific HDMI port on your TV that is used to connect to the ATV 4K is DV capable.

Also, is the ATV 4K connected to a standard HDMI port on the TV or is it connected to the HDMI-CEC port. It shouldn't matter, but just for the sake of analyzing the issue...
Thanks for the reply.
It's very odd - I've tried two different HDMI cables, both high speed, 2.1 certified and the ATV 4K has tested them both as being fully capable. I've also tried the high speed Belkin cable that Apple always recommend and it produces the same results.
I've also tried different HDMI ports on the TV, avoiding the ARC port, but the image always ends up the same. I've tweaked every setting I can think of on the TV, including the 4K direct option which bypasses all picture processing, and I've made sure that it's switched to Mode 2 which allows for full bandwidth UHD to be received, but no improvement.
I might take it up with Panasonic and see what they say. It's very odd. I keep wanting to blame the TV but why does the 4K Firestick produce perfect Dolby Vision on the same HDMI port with the same settings?
 

w5jck

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Nov 9, 2013
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I suspect it is some TV setting. I know nothing about Panasonic TVs though. I know it works fine on my Sony Bravia.
 
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priitv8

macrumors 68040
Jan 13, 2011
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I suspect it is some TV setting. I know nothing about Panasonic TVs though. I know it works fine on my Sony Bravia.
Could be that Bravia is a player-led DoVi (LLDV) display and Pana is expecting TV-led DoVi.
I am not sure how appleTV handles TV-led DoVi output.
 

BellsWhistles

macrumors member
Aug 17, 2009
70
42
California
I have the latest gen 64Gb ATV 4K box hooked up directly to my Panasonic GX800 TV which is Dolby Vision certified. I use a certified HDMI cable which passes all the A/V tests and everything works really well, except for Dolby Vision content.
All Apple TV+, Netflix and Disney+ 4K content in Dolby Vision suffer from incredible black crush, with lots of near-black flashing, posterisation and visible artefacting, particularly on dark scenes. If I play the same content via the TV's apps with exactly the same Dolby Vision picture settings, it plays back flawlessly in Dolby Vision and looks much better than via the ATV. What am I doing wrong?
I have tried tweaking every setting I can find on both the TV and the ATV 4K box but can't find a way to improve things. Does anyone have any suggestions or do I have a faulty box? I can play Dolby Vision content from other sources perfectly fine on the TV - I have a 4K Firestick which works fine, and a 4K BluRay player which also exhibits none of the problems with Dolby Vision encoded discs.

My ATV settings are:
Format: 4K SDR
HDMI Output: YCbCr
Chroma: 4:4:4
Match Content: Range & Frame Rate

Everything switches properly in terms of frame rate and dynamic range. SDR & HDR10 content looks great, it's just Dolby Vision that gives me these issues.
Any suggestions much appreciated.

I think if your AppleTV does not display Format 4K HDR, it will not be possible to view dolby vision. It could be the age of the equipment and some disparity with protocols. Once you get the AppleTV to select 4K HDR and run the self test at selection time, it should probably work after a successful link.
 

DenisK

macrumors regular
Nov 6, 2008
173
28
Well, if any help, I do have very similar issues with *some* content in Dolby Vision from ATV4K, and it is fine on some other, and I haven't been able to find predictors yet. The only thing that remedies this for me so far is to switch ATV4K to the 4KHDR output and then its all fine. My TV is the latest Xiaomi TV Q1E 55, which supports Dolby Vision.
 

Prorege1

macrumors regular
Jun 21, 2020
224
319
We have a new Hisense 4K TV which is able to play Dolby Vision. On our ATV 2021 I change the video format to Dolby Vision (not SDR/HDR) and it just works.

We also have a 2018 Samsung 4K TV which can't play Dolby Vision, on this TV the ATV 2021 only gives the option for SDR/HDR, not Dolby Vision.

Is the Dolby Vision option available on your ATV?
 

George Dawes

Contributor
Jul 17, 2014
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I didn’t realise Panasonic TVs supported Dolby vision, I know the last gen didn’t , might be the problem ?
 

w5jck

macrumors 65816
Nov 9, 2013
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We have a new Hisense 4K TV which is able to play Dolby Vision. On our ATV 2021 I change the video format to Dolby Vision (not SDR/HDR) and it just works.

We also have a 2018 Samsung 4K TV which can't play Dolby Vision, on this TV the ATV 2021 only gives the option for SDR/HDR, not Dolby Vision.

Is the Dolby Vision option available on your ATV?
Both ATV 4K 2017 and 2021 have the DV option, but that is a really sucky option since it keeps DV on all the time thereby overriding all other formats and it makes the menus way too bright. You are experiencing 90+% of the programming being presented in a format it was not created in by FORCING everything into a simulated DV.
 
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w5jck

macrumors 65816
Nov 9, 2013
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I didn’t realise Panasonic TVs supported Dolby vision, I know the last gen didn’t , might be the problem ?
Indeed. The two people complaining about this issue have have lesser popular brands of TVs, which makes me wonder if those off-brands simply don't support DV properly.
 
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SnippetySnip

macrumors newbie
Original poster
Jan 10, 2022
22
3
Thanks for all the responses. I suspect it is a Panasonic thing. The TV is fully Dolby Vision capable and plays DV from other sources absolutely fine. This is the model I have:

https://www.panasonic.com/uk/support/discontinued-products/televisions/tx-50gx800b.html

It's a 2019 model so not exactly ancient. The Dolby Vision flag is triggered when I play DV content from the ATV and the TV switches into Dolby Vision Dark/Bright/Vivid mode automatically, it's just that it seems to give a very poor image quality in comparison to the same content from other sources.
DV from my 4K Firestick looks fine. DV from my 4K BluRay player looks fine.

Could be that Bravia is a player-led DoVi (LLDV) display and Pana is expecting TV-led DoVi.
I am not sure how appleTV handles TV-led DoVi output.

I think this could be something to do with it. Is there a way to switch between player-led and tv-led Dolby Vision?
 
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ahsia

macrumors newbie
Oct 30, 2020
26
16
Hi there op. There’s no way to dictate player or tv led dv priority. I noticed that you listed your chroma settings as 4:4:4. Unless you are using the panny as a computer monitor, you should set it to 4:2:2 or even 4:2:0. All it does is help sharpen text for computer graphics and all material these days are sent as 4:2:0. Basically wasting whatever bandwidth you have. On the at4k side be sure to enable dv and match frame rate. Are you in Europe?
 

SnippetySnip

macrumors newbie
Original poster
Jan 10, 2022
22
3
Hi there op. There’s no way to dictate player or tv led dv priority. I noticed that you listed your chroma settings as 4:4:4. Unless you are using the panny as a computer monitor, you should set it to 4:2:2 or even 4:2:0. All it does is help sharpen text for computer graphics and all material these days are sent as 4:2:0. Basically wasting whatever bandwidth you have. On the at4k side be sure to enable dv and match frame rate. Are you in Europe?
I am in Europe, yes.
It’s very odd, I’ve tried 4:2:0 for the chroma output and let the ATV recheck the connection but the Netflix DV output is still the same.
I’ve also tried RGB High & Low with no change.
It’s like there’s a ton of extra unwanted picture processing added and all dark areas of the frame just disappear in a distracting mush of near-black artefacting. The final episode of Midnight Mass for example is particularly bad. The same scenes on the Netflix app on the TV look infinitely better - the dark areas have detail with no artefacts. The Dolby Vision Dark settings are the same for both.
I’ve checked the HDMI settings on the TV, I’ve tried different ports, and no change, so I’m out of ideas.
It’s a shame because everything else on the AT4K box looks great - DV on Disney+ doesn’t exhibit the same problem, it just seems specific to Netflix.
Perhaps it’s just a quirk of the ATV Netflix app with my TV?
 
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JBGoode

macrumors 65816
Jun 16, 2018
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Both ATV 4K 2017 and 2021 have the DV option, but that is a really sucky option since it keeps DV on all the time thereby overriding all other formats and it makes the menus way too bright. You are experiencing 90+% of the programming being presented in a format it was not created in by FORCING everything into a simulated DV.
You know you can just set the ATV to 4k SDR and enable match dynamic range to prevent this right? Then only DV content will display DV and everything else will be SDR including your menus.
 
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Meuti

macrumors regular
Dec 8, 2019
118
68
I have nothing technical to add to this conversation or to guide you. But try one of the movies that has the muddy dark scenes while setting your TV (not the ATV) to Sports Mode (or something sounding similar in the settings). The goal is to turn motion smoothing on.

I have my TV set to Cinema Mode which basically disables any interpolation by the TV while watching a movie. Now sometimes I have movies in which the same dark, muddy shadows come up and it's a pain to watch them. If I turn off the cinema mode and let the TV do it's "magic" the movie gets a lot more "lightened up" and everything looks fine. I only turn it on when I have movies with the described problem, after that I always go back to Cinema Mode, because I like it a lot better.

Here's an article describing the whole thing (even though it has nothing to do with your actual problem, I think there might be a connection somehow :D) Just give it a shot.
 

HDFan

Contributor
Jun 30, 2007
4,526
1,683
I've tried two different HDMI cables, both high speed, 2.1 certified

What is the certification authority? If they were self-certified (by the manufacturer) then it can't be trusted. You want something certified by HDMI.org.

For HDMI 2.0 you would look for:

Screen Shot 2022-01-15 at 11.46.14 PM.png



For HDMI 2.1 (8K) certified cable you would be looking for:

Screen Shot 2022-01-15 at 11.42.33 PM.png


It's a long shot but the HDMI cable is the weakest link in the chain.
 
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SnippetySnip

macrumors newbie
Original poster
Jan 10, 2022
22
3
What is the certification authority? If they were self-certified (by the manufacturer) then it can't be trusted. You want something certified by HDMI.org.

For HDMI 2.0 you would look for:

View attachment 1944943


For HDMI 2.1 (8K) certified cable you would be looking for:

View attachment 1944942

It's a long shot but the HDMI cable is the weakest link in the chain.

Yup, both cables I’ve tried were HDMI.org certified, checked via the app and QR codes.
No changing of picture modes, cables or HDMI input settings on the TV seem to make a difference, so I guess I’ll carry on using the TV Netflix app rather than the ATV box. Shame.
 

coso

macrumors 6502a
Feb 9, 2012
862
491
DV content seems darker on my Sony X900H too than native apps on my 2021 ATV 4K. I read it's because Sony implements a "low latency" DV profile, which require external processing, but all external boxes pass the DV signal as it is for processing, thus the light levels are wrong.

There was an hardware problem on all first generation 4K ATVs though, that crushed blacks especially noticeably on OLED panels. Reddit and avsforums have lots of content on this

Still not sure though, I'm really liking the ATV but this is a bummer
 

priitv8

macrumors 68040
Jan 13, 2011
3,956
601
Estonia
Not exactly correct because appleTV 4K was the first commercially available external box to implement Sony-compatible low-latency Dolby Vision (LLDV).
Sony”s own DV capable (also Sony LLDV compatible) bluray player UBP-X700 appeared only in 2018.
 
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SnippetySnip

macrumors newbie
Original poster
Jan 10, 2022
22
3
Check if you need to enable deep colour on your HDMI port. Also save up for a OLED tv so you can get true blacks ;)
Oh yes, I am indeed intending on switching to an OLED as soon as funds allow!
I've checked the HDMI port on the TV - it's set to Mode 2 (Panasonic's version of deep colour) which allows the full bandwidth of UHD/HDR content to be received. No change.
It's definitely something to do with how the TV receives HDR & Dolby Vision via HDMI. I've tried turning HDR off on the TV settings and reset the HDMI handshake between it and the ATV box so that the ATV only outputs an SDR signal. Netflix reverts to 4K SDR and looks much better - much more like the Dolby Vision version I get via the TV app. Blacks are blacker, there is detail in the near-black areas of the frame, no artefacting or crushing. The image is just overall sharper and more pleasing to the eye. Very strange.
I'm going to get in touch with Panasonic and see if this is something they are aware of.
 

muddy250

macrumors newbie
Jan 21, 2022
2
1
Have exactly the same issues with the same TV using a new ATV 4k here. Interested to know what Panasonic have to say about it if you do contact them.
 
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SnippetySnip

macrumors newbie
Original poster
Jan 10, 2022
22
3
Have exactly the same issues with the same TV using a new ATV 4k here. Interested to know what Panasonic have to say about it if you do contact them.
I have contacted them so I'll let you know when/if I hear back from them.
 
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