Black clips at 85 for Dolby Vision output only **SOLVED**

**This issue has now been solved - details start here:
http://forum.zidoo.tv/index.php?threads/black-clips-at-85-for-dolby-vision-output-only-solved.94541/page-5#post-179701 **

oOo

I open a new thread to discuss a problem with the Realtek SOC RTD1619DR



About 1 month ago a problem was pointed out by the member ''Sekology'' on the Zidoo forum concerning concerning a problem of Black clips at 85 for Dolby Vision output only, thanks to him.

http://forum.zidoo.tv/index.php?thr...o-x-neo-s-neo-alpha.94137/page-13#post-177246

Zidoo has been made aware of the problem and has notified the company Realtek which produces the RTD1619DR to inform them of this problem, we are in the month of October and unfortunately Zidoo has apparently no news from them on this subject.

Let's underline Zidoo's reactivity, and let's be clear that the problem comes from the Realtek SOC, and therefore Zidoo has no control on the possible resolution of this problem or not and
it also means that all multimedia boxes using RTD1619DR are affected by this problem.


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What is (black) clipping ?

Clipping occurs when certain areas of an image contain no information.

When an area contains no information, it is either pure black (shadows cut off) and the reverse is also true... purely white (cut highlights).

Clipping is a result of processing an image where the intensity in a certain area falls outside the minimum and maximum intensity which can be represented.



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For a few days I have been exchanging with different people on different forums about the Black clips at 85 for Dolby Vision output only with the Realtek SOC.

And comparisons have been made with the following devices: Zidoo/Dune HD/ Zappiti RTD1619DR, Shield TV PRO, Apple TV 4K, Oppo and Sony X700 with Dolby Vision test patterns.

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For Dolby Vision only...

The Dune HD, Zappiti and Zidoo 1619DR boxes all clip at 85 which is roughly 2.4%. This means that there are 21 levels of grey missing between black and the clip point at 85.

The Oppo 203 clips at 78 (1.6%) and the Sony X700 UHD BluRay player clips at 77 (1.6%) for the same Dolby Vision signal.

The Apple TV and Nvidia Shield have been observed to clip correctly at 64 (0%).

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Most people I've talked to agree that the problem is mostly visible with test patterns and less discernible in normal viewing conditions.

Unfortunately, other more sensitive users can see the difference and use their Shield TV or other devices for the moment, preferring to wait for a fix to be proposed by Realtek

Here is an example GIF of 2 images (shared by the member Sekology, with his Zidoo and his Shield TV PRO) of 5 seconds each and which shows you an example of what is the loss of information in the shadow zone with the Realtek SOC



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They are sure that some users can live with it... but anyway, there is a problem with the Realtek RTD1619DR concerning this precise point in Dolby Vision (black clips at 85 in Dolby Vision only).

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Hopefully, Zidoo will do its best to get Realtek to fix this problem.

OlivierQC


​

 

I forgot to specify to leave a small message to show Zidoo that we attach importance to this concern otherwise this thread will disappear in the flood of messages that receives the forum every day

See you soon​

 

@OlivierQC
Great work, shining a light on this issue, for me personally, it is a BIG issue because I bought the z9x specifictly for playback of Dolby Vision content, and this is a crippling issue for videophiles like myself, especially because correct Dolby Vision was the sole purpose of buying the z9x, and adding it to my home theater setup
Well let's hope that Zidoo and Realtek can come up with a solution and a fix for the problem, let's see what happens
I any more info or anything else is needed to clarify and shed light on the subject, I will do what I can to help and provide information and documentation

Cheers....
Dennis

 

Not sure if even Realtek can do something about. I assume Dolby has to fix it….
The Roku Ultra uses the RTD1319 which I assume has the same issue. If they have a public forum it might be a good idea to post it there as well.

 

It's also interesting that other "big name" boxes have the same problem - my Sony BD player for example, the Oppo BD players (which also use VS10).

As it says above, the only devices I've seen so far that hit black at 64 are the Apple TV and Shield - it'd be interesting to get feedback for other devices.

I don't actually think it's as huge a deal as it seems because of the way PQ gamma works, but obviously it'd be nice if it was right!

 

Well it would be safe to assume that the problem lies with Realtek, since other devices based on other chipsets are able to display Dolby Vision the correct way without black clipping....
It is definitely not a Dolby Vision issue that Dolby can solve since the issue is not on their end....

 

I will be happy to test with the Spears and Munsil UHD HDR Benchmark blu-ray on my Xbox Series X and Panasonic DP-UB450 and see where they clip the picture?

 

That won't work - that disc is HDR10 only so it will clip correctly at 64 or thereabouts.

You need a Dolby Vision test pattern.

 

I was pretty sure that there were some Dolby Vision tests on this disc, but it's probably just me not remembering correctly, sorry about that....
This is the disc I currently have:
https://www.avforums.com/reviews/spears-munsil-uhd-hdr-benchmark-4k-blu-ray-review.16440/

 

Good point. But I still wouldn’t rule either way out.
Several devices are not able to do so. Output between Panasonic UB9000 and Oppo 203 is different. Raised blacks on AppleTV to name a few.
We don’t know what Dolby SDK they are using and what versions are offered to them.

 

No DV on them. They are still working on a new 3 disc set which includes DV.

 

There are a couple of Dolby Vision demo sequences but no test patterns.

 

My guess, sometime in 2030.

 

That's a good point

 

They found several bugs in encoders and authoring software that needed to be fixed. But yes, it’s been a long time

 

Just popped the disc in my Panasonic and you're absolutely right, I stand corrected

 

It's been a ridiculous amount of time. Diversified Video came out with theirs a couple of years ago..

And why they're fannying around with SDR, HDR10 and Dolby Vision I have no idea!

 

Hello Sledge,

Give me a link and I will do it if necessary

 

This looks like a good place:
https://community.roku.com/t5/Playback-Issues-Audio-Video-Power/bd-p/audio-video

 

Thanks, I'll do it tomorrow and I'll maybe modify the thread a bit for this forum

Just to be sure we are talking about the soc rtd1319 and not the new D version with this roku?