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

Thanks Olivier!
Yes, “just” the RTD1319.

 

Thank you for putting together this post. This is exactly the issue I'm seeing in real life content, not just test patterns. I had mentioned this issue before to Mark.

Unfortunately, I'm one of those people that are sensitive to this issue, which means for me I can't watch DV content on my Zidoo.

Let's hope the issue gets fixed soon by Realtek.

.

 

You are not alone mate, for me in a darkened home theater, this makes my z9x useless on my ISF calibrated display

You are not alone mate, the issue makes my newly bought z9x useless for dolby vision playback on my ISF calibrated display in a darkened home theater, unfortunately

 

If this issue cannot be resolved via firmware update it may fast track a
new Realtek chipset sooner rather than later.
Which is well been overdue.

So the 1319D is not effected then ?

 

Well, let's hope Realtek fix the issue, as I'm not sure I would buy an "upgrade" after shelling out for my Z1000pro only to find DV content is borked.

 

The Zidoo release new models every two years normally and we were due it in June / July this year
and many would of upgraded if the newer spec ticked there box etc

But there has been a delay …….

So you so called Z1000 Pro model is nearly 2.5 Years Old already.
Fingers cossed it gets resolved .

 

I can not help but notice this in real life content. The device is just sitting on the shelf and collecting dust. You have prepared everything for illustration very nicely. If this bug is something that Realtek really intends to fix, it is just enough if they take a look at your screenshots. The proof is out there. I was hoping that this would get fixed with the new firmware but unfortunately, it still persists despite having this reported long time ago..

 

Yes this really needs to be fixed. Obvious in a lot of real world content.

 

Hello,

For those who want to see for themselves here is a Dolby Vision compatible test pattern

Dolby vision pattern test FREE

Thanks to the person who shared this DV test pattern.

They're based on Mehanik HDR10 patterns which are freeware with an RPU slapped on the side.

MKV:
https://mega.nz/file/5awBkb6L#fI3HZE28l90-JxPY-7xU0m1LAHiYXFTK2Wwo_mXmXNo

MP4:
https://mega.nz/file/ZP42iTxK#9wIBmkEqEy4o8ZszDn4NhriARe0qYRpEEH_wzjGHRSI

See you soon​

 

These patterns aren't as good as the Spears & Munsil patterns since they don't resolve to individual 10-bit quantisation levels, they're at 4 level intervals, but you can see the cut off between 88 and 84.

Bear in mind that your display and ambient light may affect perception so to negate the effects of display calibration and see the effect of source playback only, a trick is to turn black level (Brightness) up to max on the display.

 

Thank you for these important clarifications my friend,

 

dumb question here but does this clipping also occur with TV-LED?

 

Yes.

 

I can feel a whole raft of black clip tests in all Realtek and VS10 modes coming on...

This will not be to expose any shortcomings of the 1619 but hopefully (depending on the results! - have to put that caveat in ) more to put things into perspective.

It used to be easy in the good old days of 8-bit video and SDR - you had 256 quantisation levels with 219 used and we were happy with that. There was one mode, one colour gamut, simple linear gamma and we were happy with that.

Now we have 1024 levels, we use 876 of them, there are multiple modes, multiple colour gamuts, variable PQ gamma - hell we even have IPT which operates completely differently to anything else!

We have big name UHD players that exhibit the same sort of clipping and as I've said, because of how PQ works, such clipping isn't anything like as dramatic as it would be if say Power gamma clipped in 8-bit at 21 (which is the equivalent of 85 at 8-bit).

No-one even noticed this before Spears and Munsil released a true DV black clip test pattern with individual quantisation levels.

I'm not saying this doesn't need fixing, but I am saying we need a bit of perspective.

The Oppo has been out since medieval times, uses VS10, and has the same clipping issue - no-one ever moaned about that - in fact most people (very wrongly!) think it's a reference player (it really isn't!).

Or Sony.

Just sticking my oar in an wiggling it a bit

 

I had noticed the clipping but wasn’t sure of the reason before the test pattern. Also the Oppo doesn’t clip as high so probably isn’t as noticeable in real world content on that.

 

Hi Mark, first of all thank you so much for all the info you have shared with us on the forum, personally I learnt a lot from you. I just compared (GOT S08E1 around 20 min. mark)between Oppo 203 and Zidoo Z10 Pro and there is no clipping with Oppo 203.

 

Can you run the S&M shadow pattern through the Oppo - we got a report that it clipped at 78.

 

I can turn my brightness up to 100, and you cannot see any other bars beyond the hard clip for DV. Normal SDR and HDR are fine.

Just sticking my oar in and wiggling it a bit

 

Hi Mark, unfortunately, I don't have this test pattern. I have tried to check it with the pattern in this thread, used tsmuxer to save the file as .ts but no luck. It felt back to HDR. I assume that 78 is correct. Regardless of that, maybe it would be enough for Zidoo to go to 78 level and we wouldn't experience any issues with black clipping in real content.

 

I have an older JVC projector and follow Mark's .PDF to the letter for setup of my Z9X for LDDV, including his custom gamma for JVC projectors. I have felt that my overall image has been a tad darker under this setup, but, in my completely blacked out dedicated room, the resulting image is simply stunning. I have no complaints as I am quite happy with what I'm seeing in terms of colour rendition, contrast and shadow detail.

Last night, after watching a beautifully rendered UHD rip of the movie CHRISTINE (HDR10 > LDDV via VS10), I decided to test out the clip uploaded by OLIVIER. The file was recognized as DOLBYVISION and exhibited the expected black crush well above the absolute absolute black level (between 88 and 84).... I then remembered that I had paid for some DV patterns a few months ago from a link over on AVS. They are in an MP4 container and are from a guy name R. Masciola (I may have the spelling wrong).

When I tried the black clipping pattern from that file, it shows that the display is in fact blinking well below the absolute black level. It was very late and I don't remember how far below the level it was, but it was significant enough that, under other circumstances, I would be inclined to lower my BRIGHTNESS level to achieve what I've known in the past to be a proper setting with such patterns. Knowing what I've read here, and trusting what my eyes generally see with actual titles, I can only assume that the pattern is off. It is definitely recognized natively as a DOLBYVISION title according to the Zidoo popup in the top right corner upon startup.

I obviously can't link the files here as I believe they are copyrighted(?). Has anyone else had experience with these paid for patterns?