Emulating the JVC X-Series with the JVC NZ Series

Edit 27 Aug 2023 – Updated the SDR section with a more balanced approach after more testing. I will update the HDR section once I had the chance to run more testing on that. It is a bit difficult to come up with a balanced approach with on-board only settings.

Edit 29 Aug 2023 – Added alternative suggestion for HDR

Edit 30 Aug 2023 – Added preface

Preface

This article isn’t talking about “reference” but more about “preference”. However, we could argue that there’s nothing “reference” about projection, especially when we are trying to emulate flat-screens.

Ultimately, there are two schools of thought for reference rendering – at least in the world HDR…

1. Anything the display cannot render should be cut
2. Anything the display cannot render should be tone-mapped

I’m somewhere in-between with this. However, while highlight tone-mapping has received a lot of attention, and research, near-black rendering has not and is in fact a bit of a mess, frankly.

So this article is just giving you levers you can pull to emulate the X series, however imperfect they are. If this topic is popular, and with time permitting, I might publish a more in-depth article on creating custom curves to do such a thing more precisely.

Introduction

I don’t generally subscribe to the camp that loves to see into every nook and cranny of dark scenes. If you do, you might want to skip this article!

On a high-contrast display, you will be able to see all the detail, but it isn’t meant to be so bright that it jumps out at you. I strongly believe that this actually reduces the contrast perception and why I actually think Sony’s approach to tone mapping is the right one – minus them falling over to the other side of the horse and cutting black detail altogether, which can also result in the same: reduced contrast perception due to big blotches of hollow screen areas.

In my review of NZ8, I lamented its contrast performance with regards to the X-series units. While it is true when simply running AutoCal, this isn’t really the full truth and it isn’t really the whole story.

The contrast differences between the two series are there, however, this isn’t really the main cause of why the NZ series can look worse with content at times, at least in my opinion.

After all, the RS20 / HD950 only had around 15,000:1 on/off contrast with the iris fully open (50,000:1 with it fully closed), but it still looked high contrast. Yes, a higher light output will perceptually lift that black floor, but again, you can go twice as bright with the NZ8 without lifting the black floor as the NZ8 has 26,000:1 of on/off at the minimum, and really around 40,000:1 in real-world usage scenarios for SDR. So ultimately, we need to hunt further as to why…

Is It the Brightness Setting (aka. Black Level)?

Some have theorised that it is the lifted digital black floor in the default state and that by bringing down the brightness slider a step (or a couple of steps), this can be remedied.

While this can help some, we need to realise that the black level on the NZ units is set correctly from factory by JVC. How do we know? Well, when measured at the lens, brightness 0 and brightness -1 measure the same: that is, there is no lifting of the black floor at 0. When you up the brightness to 1, however, there is a lifting of the black floor and a difference in brightness measurements, as expected.

The Real Reason

So if it isn’t the brightness, then what is it?

It is actually how near-black gamma is handled on the X series and the NX / NP / NZ series is the real culprit here. While the X series (and the HD series before it) came out of black very slowly, similarly to an OLED, the NZ (NP and NX) series units come out of black a lot quicker, even with all things being equal, e.g. running AutoCal correctly. (See here if you don’t know how to run AutoCal.)

I can only theorise why this is. There were numerous complaints of the X series units crushing shadow detail, and near black gamma being too aggressive. It certainly was out of the box, but Autocal helped greatly. Maybe JVC is shooting for something closer to BT.1886 – which in my opinion is a misguided standard that only works for correctly authored content – so in dreamland.

Why do I say that? Well, while this lifting of near-black gamma improves shadow detail, it is actually to the detriment of a lot of content. This is because content has somewhat variable black floor unless it is digitally checked and aligned during mastering. The truth is, it isn’t most of the time. So while this content will look correct when viewed on a high-brightness display (such as a flat panel or a mastering monitor), an OLED or a previous-generation JVC, it will not look correct if the near-black gamma is lifted, even with the correct digital black level setting.

This is why a lot of content can look a little murky and lacking in contrast from the NX series onwards – as the black floor isn’t quite black in lots of actual content.

Solution for SDR

Edit – 27 Aug 2023 – A more balanced solution is offered at the end of this section

I may give the manual calibration steps in another article for those that want to mess with 100-step gamma, but this is Simple Home Cinema after all, so I need to give you something that doesn’t require a degree in calibration and is workable. Thankfully, we do have the second best thing, at least for SDR content: the on-board custom gamma sliders.

So I went ahead, set up the X7000 and NZ8 with the same content: Alien and Aliens, and I went to match them. For the NZ8 after a just completed quality gamma autocal, it looked as follows: dark level at -2. While the below image has a 2.4 gamma, the gamma will vary between 2.3 or 2.4 dependent on your unit and your viewing environment.

After this, I checked out a lot of other content and ultimately settled on 2.4 gamma with -2 dark level for my viewing conditions. The main thing is the dark level setting, though. While this isn’t a perfect way to tackle near-black detail, it is better than leaving the lifted near-black detail in my opinion, and removes a lot of the low-level “haze” that is present on these units.

If I had to recommend a setting that will work on all units without crushing shadow detail, it’d be 2.3 gamma with -2 Dark Level – as long as you are in a pitch black room.

Now with regards to the other units, I would recommend the following:

JVC Model	Brightness	Gamma	Dark Level
NP5 / NZ7	0	2.3	-1 or -2*
NZ8	0	2.3. or 2.4	-2
NZ9	0	2.3. or 2.4	-2
NX5	-1**	2.3	-1 or -2*
NX7/NX9	-1**	2.3 or 2.4	-1 or -2*

SDR – A More Balanced Solution

After doing more testing, and without doing a custom gamma import, I think a more balanced solution for most units is as follows:

• Brightness: -2
• Gamma: 2.3
• Gamma Dark Level: -1

The issue with messing with dark level too much is that it is affecting the gamma higher up than desirable of course, not just under 2% where the issue is.

While the black level seems to be set correctly, there’s room to lower it to -2 without cutting much content as low-end gamma is lifted enough that you wouldn’t be able to see much around there anyway. It actually takes down to -3 to start cutting the level above black even though the black floor isn’t lowered. It’s a bit of a bizarre behaviour – at least on my unit.

Based on the above, it is likely that HDR will land around -3 brightness and backing off on the Tone Curve (black) adjustment by a touch as well, but will do more testing.

Solution for Frame Adapt HDR / DTM

Edit – 29 Aug 2023 – Added option 2B.

This is where JVC’s insistence that we don’t manually alter the gamma for Frame Adapt HDR comes to bite us in the @$$. There is no way to perform the same trick for the on-board tone-mapping. So we have only partial and non-ideal solutions. However, the solutions from best to worst are as follows:

1. If you are using external tone-mapping then map to an SDR gamma and do the same trick as above in the JVC. This is pretty much a perfect solution as long as the external tone-mapping is playing ball.
2. If you are using Frame-Adapt HDR and you have a player that can change the low-end near black gamma (such as a Panasonic UHD Blu Ray player), then configure the near-black gamma in the player by bringing it down a few steps.
3. If you are using HDR with streaming primarily or you have a Blu Ray player without gamma controls, then the only solution is the big bad hammer called the Brightness control.

Option 2A. Panasonic UHD Player Settings

Since option 1 is clear enough, let’s cover option 2. On Panasonic UHD Players, there’s a setting in the options menu under Luminance / Color Adjustment called Tone Curve (Black). This needs to be pulled down 2 to 4 clicks dependent on the JVC unit you have, and your preference for shadow detail. -3 seems to be a good compromise on my unit.

While this setting looks a visual match to the X-series at -3 on my NZ8, let me include some recommendations per unit again. Please consider that I didn’t test this on all units, I am just exercising judgement based on the unit’s expected black floor and contrast performance. You should test your unit with these settings – preferably after a gamma AutoCal.

JVC Model	Tone Curve (Black) Setting
NP5 / NX5 / NZ7	-2 to -3
NZ8	-3 to -4
NZ9	-3 to -4
NX7/NX9	-3 to -4

Option 2B. Panasonic UHD Player Settings – Alternative hybrid option

I had another look at this and a hybrid option is also possible here – and even preferable – whereby both brightness control and the tone curve are amended.

Again, the black level is set correctly for HDR on the NZ8, however, there is room to lower it to -2, which gets us into Dolby Pulsar black floor territory. The Dolby Pulsar is admittedly a great mastering monitor for Dolby Vision so trying to emulate that here isn’t the end of the World.

I would argue that anything below that level isn’t quite easy to distinguish on the NZ8 since it doesn’t have the black floor to do so. But in the strictest sense, it is cutting content off near black.

Now when this is combined with adjustment of the tone curve for the Panasonic Blu Ray player, then we get something approaching an X Series in terms of looks while still resolving HEAPs more shadow detail compared to an Epson or a Sony. So ultimately, this is still excellent.

One advantage of doing this hybrid approach is also that both streaming and disc media benefits without having to have two memory slots.

JVC Model	Brightness (Black Level)	Tone Curve (Black) Setting
NP5 / NX5 / NZ7	-2	-1 to -2
NZ8	-2	-1 to -2
NZ9	-2	-1 to -2
NX7/NX9	-2 to -3	-1 to -2

Option 3. Brightness Control

Now let’s cover option 3. I am not necessarily endorsing this approach as it is a very blunt instrument and it messes up other things, but here we go.

If you need to use the brightness control, you will have to pull it down to around -10 to provide something approaching a visual match to the X series. This will cut quite a bit of content off for HDR that has correctly mastered black levels and the grading sticks to it religiously. So to provide a better compromise, you may want to settle somewhere between -5 and -3 for brightness.

While this doesn’t provide a visual match, it still provides enough shadow detail, while blunting the massively lifted blacks in a lot of HDR titles. However, of course you will crush some near-black detail. There’s simply no way around this. So you need to pick your poison: have lifted blacks and too bright near-black detail or crush near-black detail in some content.

Solution for Static HDR (for Gaming for example)

Some people use Frame Adapt HDR for gaming, while others will opt to use static HDR for gaming due to latency. To get static HDR to look adequate, I would recommend to use the HDR10 mode, choose HDR (PQ) Gamma and then set up the gamma sliders under it as follows:

• Picture Tone: +5
• Dark Level: -2 to -4
• Bright Level: +7

This will provide a 400nit cut-off but a bright enough HDR for gaming. Since the consoles – and Windows – can be configured for whatever display brightness, this should provide a brighter HDR without clipping while also addressing the near-black gamma issue.

Below is also a less aggressive version with around 500nit cut-off:

• Picture Tone: +3
• Dark Level: -2 to -4
• Bright Level: +6

Request to JVC

The first request I have to JVC is to allow manipulation of the gamma that is used for Frame Adapt HDR. I just feel that relying on the onboard gamma is not really adequate, especially since the same is applied to the NP5 as to the NZ9. I am not sure this is adequate, when the high-end units have a lot more dynamic range near black.

If that is not possible, then I think it would be beneficial to allow for the black floor to be dynamically mapped to a particular Black Level level using an additional control called the HDR Black Level. For example, if I were to pull down the HDR Black Level to -7, which corresponds to -7 on the brightness slider, then the DTM algorithm would check if the current frame had information above this (so between -7 and 0). If it did, then it would map the black floor to the pixel with the lowest luminance in the scene. If it didn’t, then the black floor would stay at -7.

This kind of change to the DTM algorithm would in fact be useful for the external tone mapping solutions as well. The current way of mapping black level for HDR content is found lacking for projectors so a change would be welcome from both JVC and the other vendors.

To go all out, JVC could split the dark level gamma setting into Near Black Gamma and Dark Level, to aid in even more granular configuration of this.

Conclusion

Anyway, I’ll leave it there. I hope this will help some people who have been struggling with content not looking as good on the NZ series and wondering why.

The above settings, especially for SDR, close the gap between the X and NZ series to a much more narrow margin, and to a point where I feel content looks incredibly similar – if not equal – to the X series with regards to contrast. In fact, watching Alien or Star Wars with these settings, I could have sworn I was watching the X series in the darkest of scenes, and it looks like a closer visual match to the OLED as well.

Black Haze Be Gone! ^TM