Official JVC RS600 / RS500 (X950R / X750R - X9000 / X7000) Owners Thread - Page 694 - AVS Forum | Home Theater Discussions And Reviews
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post #20791 of 31987 Old 02-13-2017, 08:04 PM
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Originally Posted by mbw23air View Post
Hey Guys,

ChadB just left a little while go after calibrating my RS600 and all I can say is WOW! He did a fantastic job. He calibrated for SDR bluray and SDR & HDR UHD bluray and after seeing results I will only be watching UHD in HDR and he agreed. He and Manni both been to the secret sauce store. Black level is now fantastic in both HDR and SDR but HDR looks superb with high lamp and Iris open. I also didn't realize how bad I was crushing shadow detail until now.

A big thanks to Kevin for posting how good ChadB did with his JVC. All my auto calibration days are over. Anybody on the fence or thinking about getting ChadB to calibrate their JVC should definitely do it. ChadB's website: http://www.hdtvbychadb.com/home-1.html

Best money ever spent on my home theater!

Time to watch movies now!

Mike
Very good to know. He will be in my home the first part of March. I want 3 settings: BR, SDR/WCG, HDR. I am not a fan of high lamp due to how close the JVC is to my ears so it will be interesting how this works out.
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post #20792 of 31987 Old 02-13-2017, 08:13 PM
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Originally Posted by stanger89 View Post
...
First, we know that SDR is mastered for 100 nits peak white, and in general we calibrate our projectors for about 50 nits peak white. Now SDR uses a relative curve, so everything scales well.

Now, for HDR, we have ST.2084 which is an absolute curve. We know that HDR is intended to be roughly the same (brightness wise) as SDR, up to 100 nits, with the range above that being for highlights.

So the question is, why do we not want to use a 2x multiplier in Calman for calibrating HDR? That would make content 100 nits equal to 50 nits on screen, which would seem to be exactly what we're looking for . Then for a custom curve, wouldn't you calibrate it "linear" all the way up to the 100 nit point, and then apply the roll off between 100 nits (is that ~50%?) and 4000 nits or so?

It seems to me that 4, 5, 6x multipliers are far too large, for example if I tell Calman to apply a 5x multiplier, and then calibrate everything "perfectly", content that's supposed to be 100 nits (per the PQ curve) will only be 20 nits, which is less than half as bright as we want (50 nits). ...
Not Manni: but I asked a similar question a few days ago, and from Manni's reply, (if I understood him correctly) I believe the answer is he is not changing the curve before about the 75% point, which corresponds to ~1000 NITS, and by scaling by a factor of 5, he gets a real peak of 200 NITS @ 1000NIT input. But for 50% video (100 NIT input), he is still getting near 100 NIT output.

As far as gamma D (or any gamma) curve in the JVC RS500/600, it's a relative curve. This is because the peak lumens out (at 100% video) depends on how far you are from the screen, how big the picture is, and what your screen gain is.

Now what I think JVC should do, is have the user input his peak NIT output on screen. This could be either as measured from a meter, or estimated by the user. (JVC could provide a table of lumens out vs the ratio picture_width/throw_distance. The table would include both power settings and several bulb ages. This should be accurate to 20-40%. Then the user can calculate peak NIT on screen = 3.4*screen_gain* lumens /( (picture width**2) *9/16) ) , picture width in meters).

With the max NIT output on screen, the "gamma" curve becomes absolute. Then JVC should provide a proper PQ curve with some user controls (e.g when to start to deviate from the PQ curve). Of course I would not hold my breath, JVC has moved on from the RS600.

BT.2390 defines how to map PQ to a display of lesser peak output than 10k NITS, and who knows whether it looks good or not. Manni01 has suggested, that it starts to early for his taste. But FYI, when using the equations in BT.2390, for a maxLUM of 100NITs, at 100 NIT input you get 50 NIT output.
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post #20793 of 31987 Old 02-13-2017, 08:16 PM
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Originally Posted by wse View Post
This thread is so technical that it's hard to follow, I know I stated this before but I wished they had a Calibration for dummies like me
Although the information posted here could seem intimidating, just remember you don't have to know EVERYTHING that's discussed. I certainly don't! If you just focus on a couple of items you will be at a great starting point;
1) learn the auto-cal procedure which, in practice, is not all that bad and
2) import one or two of Manni's custom gamma curves to your JVC.

The rest will come in time. Of course, hiring someone like ChadB will solve all your problems
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post #20794 of 31987 Old 02-13-2017, 08:19 PM
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Originally Posted by audioguy View Post
Very good to know. He will be in my home the first part of March. I want 3 settings: BR, SDR/WCG, HDR. I am not a fan of high lamp due to how close the JVC is to my ears so it will be interesting how this works out.
He told me he can do HDR at low or high lamp but he says he gets better results at high lamp so I had him do HDR in high lamp. Im sure it will look great either way you choose.

Mike
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post #20795 of 31987 Old 02-13-2017, 08:22 PM
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Originally Posted by stanger89 View Post
OK, now I just blazed through the last few pages, so forgive me if I missed something, but I've been thinking about this....

First, we know that SDR is mastered for 100 nits peak white, and in general we calibrate our projectors for about 50 nits peak white. Now SDR uses a relative curve, so everything scales well.

Now, for HDR, we have ST.2084 which is an absolute curve. We know that HDR is intended to be roughly the same (brightness wise) as SDR, up to 100 nits, with the range above that being for highlights.

So the question is, why do we not want to use a 2x multiplier in Calman for calibrating HDR? That would make content 100 nits equal to 50 nits on screen, which would seem to be exactly what we're looking for . Then for a custom curve, wouldn't you calibrate it "linear" all the way up to the 100 nit point, and then apply the roll off between 100 nits (is that ~50%?) and 4000 nits or so?

It seems to me that 4, 5, 6x multipliers are far too large, for example if I tell Calman to apply a 5x multiplier, and then calibrate everything "perfectly", content that's supposed to be 100 nits (per the PQ curve) will only be 20 nits, which is less than half as bright as we want (50 nits). This is actually what I found myself when I was playing around with the multiplier in Calman, I attempted to calibrate with a very high multiplier (like 10x) because I had calibrated to a peak white of under 100 nits (iris was somewhat closed), the result was everything was way too dark, much darker than if I had my Pansonic do DRC and output SDR.

I do intend to try and make my own custom PQ/Gamma curve when I get some time to play with it. I really want to try a 2x multiplier. If I understand how that works in Calman, that should be the HDR equivalent of how we calibrate SDR.

Of course the trick is, that curve will be unique to each particular setup (screen size, aperture, lamp, throw, etc).

I'm not criticizing at all, bravo for all the great work and information you've provided. Just trying to understand and hopefully help get to the bottom of this.

Thanks to the great info here and with Calman, it's invaluable.
I actually agree with this. It doesn't leave a lot of headroom but it is likely the only way to ensure tone-mapping that's kind of faithful to the original. I mean by this analogy we should really map 100nits to 100nits straight and then tail off the rest of the curve to allow for some highlights. It likely wouldn't work very well, though, in creating the illusion of HDR. It would just be SDR with not much dynamic range in the highlights. Dolby Vision, where are you? :-/
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post #20796 of 31987 Old 02-13-2017, 09:17 PM
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Is it recommended to do another AutoCal run after import the new custom Gamma curves? I just did an AutoCal a few weeks ago, but before Manni released those.
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post #20797 of 31987 Old 02-13-2017, 09:22 PM
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Originally Posted by audioguy View Post
Very good to know. He will be in my home the first part of March. I want 3 settings: BR, SDR/WCG, HDR. I am not a fan of high lamp due to how close the JVC is to my ears so it will be interesting how this works out.
Chad and I exchanged a few text messages today after reading about his findings in regards to a custom Gamma setting. He was just at my place two weeks ago, so I wanted to see if he would need to make adjustments on my system.

Based on my screen type, screen size and not wanting to have high lamp mode engaged he still thinks the SDR 2020 will be the better option for me. My projector is too close to me to have high lamp mode engaged.
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post #20798 of 31987 Old 02-13-2017, 09:30 PM
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Originally Posted by danbez View Post
Is it recommended to do another AutoCal run after import the new custom Gamma curves? I just did an AutoCal a few weeks ago, but before Manni released those.
it's not necessary as it calibrates all gamma modes, try importing the curve and running the A/B comparison between Gamma D and custom 3, it won't be hard to know which one is which.

for those with the Panasonic UB900, if you pause for extended periods of time I have seen the JVC switch back to Gamma D. keep an eye on this during testing.
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post #20799 of 31987 Old 02-13-2017, 09:36 PM
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Originally Posted by zombie10k View Post
it's not necessary as it calibrates all gamma modes, try importing the curve and running the A/B comparison between Gamma D and custom 3, it won't be hard to know which one is which.

for those with the Panasonic UB900, if you pause for extended periods of time I have seen the JVC switch back to Gamma D. keep an eye on this during testing.
Thanks! I will try it tomorrow night and report back. My setup is a 107 diagonal screen, 1.1 gain.
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post #20800 of 31987 Old 02-13-2017, 10:07 PM
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I imported two low lamp gammas; 140-1000-4000 and 140-1000-1000.

140-1000-4000 worked really well for the 4000 nit Fury Road. Two other 4000 nit discs; Jupiter and Pacific Rim, while better than I could previously get in HDR, were still darker than I would like. Just as Manni had suggested we would find if we had a larger screen than his.

After using both the black and the white clipping patters for the 140-1000-1000 gamma, I preferred it over the 4000 nit gamma when viewing 1000 nit discs. I got just a bit more brightness with it. It worked really well with Lucy. A darker 1000 nit disc, John Wick, was still darker than I would like, as I expected.
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post #20801 of 31987 Old 02-13-2017, 10:28 PM
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my 2.8HP @ 142" has a big impact on the overall HDR presentation. brightness wasn't the issue in my setup, it was the terrible overall tone of Gamma D. overcooked highlights, weak mid-range, poor shadow details. so many attempts to get it right but Gamma D was the bottleneck.

now the tone is much more even across the image and bright enough where i can clamp the iris down quite a bit in high lamp or run low close to wide open.
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post #20802 of 31987 Old 02-13-2017, 10:50 PM
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Do any dealers or reviewers following this thread know the best way for JVC to understand these (hopefully) simple change requests and consider providing them in the interest of very much improved customer satisfaction and continued brand loyalty? These changes will help all of their RS4x0/5x0/6x0 customer base that used HDR.

I say dealers and reviewers because I don't think JVC Japan is going to listen to end customer requests, but might listen to folks with a little more influence to their bottom line.
Someone at AVS should establish a conduit to JVC Japan. An influential site such as this, would be a perfect sounding board for JVC to keep an eye/ear on as to the wish list of their core customers.

Satisfy this demanding bunches wants or most of the wants anyway and the rest of the consumers needs will be surely sated.
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post #20803 of 31987 Old 02-13-2017, 11:25 PM
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That's exactly what I was thinking. AVS along with other JVC dealers and reviewers that definitely read this thread (you know who your are).

These are the folk that can get the ear of JVC better than our rants/wishes in this thread. Manni's list is pretty much complete, but I'd settle for no. 1 (working DI fade2black in HDR) and either no. 3 (allow selective Gamma choice setting for HDR instead of GammaD default) or no. 4 (individual IR codes for Gamma settings). If we got no. 3, we wouldn't even need no. 4 really. No. 2 is a nice to have improvement for GammaD, but with custom gamma curves, is no longer that important IMHO. No. 1 and no. 3 would be good enough for me.
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post #20804 of 31987 Old 02-14-2017, 02:24 AM
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Quote:
Originally Posted by stanger89 View Post
OK, now I just blazed through the last few pages, so forgive me if I missed something, but I've been thinking about this....

First, we know that SDR is mastered for 100 nits peak white, and in general we calibrate our projectors for about 50 nits peak white. Now SDR uses a relative curve, so everything scales well.

Now, for HDR, we have ST.2084 which is an absolute curve. We know that HDR is intended to be roughly the same (brightness wise) as SDR, up to 100 nits, with the range above that being for highlights.

So the question is, why do we not want to use a 2x multiplier in Calman for calibrating HDR? That would make content 100 nits equal to 50 nits on screen, which would seem to be exactly what we're looking for . Then for a custom curve, wouldn't you calibrate it "linear" all the way up to the 100 nit point, and then apply the roll off between 100 nits (is that ~50%?) and 4000 nits or so?

It seems to me that 4, 5, 6x multipliers are far too large, for example if I tell Calman to apply a 5x multiplier, and then calibrate everything "perfectly", content that's supposed to be 100 nits (per the PQ curve) will only be 20 nits, which is less than half as bright as we want (50 nits). This is actually what I found myself when I was playing around with the multiplier in Calman, I attempted to calibrate with a very high multiplier (like 10x) because I had calibrated to a peak white of under 100 nits (iris was somewhat closed), the result was everything was way too dark, much darker than if I had my Pansonic do DRC and output SDR.

I do intend to try and make my own custom PQ/Gamma curve when I get some time to play with it. I really want to try a 2x multiplier. If I understand how that works in Calman, that should be the HDR equivalent of how we calibrate SDR.

Of course the trick is, that curve will be unique to each particular setup (screen size, aperture, lamp, throw, etc).

I'm not criticizing at all, bravo for all the great work and information you've provided. Just trying to understand and hopefully help get to the bottom of this.

Thanks to the great info here and with Calman, it's invaluable.
As I said, the multiplier is related to the peak brightness you use. If you use high lamp, you can use a lower multiplier than in low lamp.

For example, to target 1000nits, I use a multiplier of 5 in high lamp and of 7 in low lamp. I would never use a multiplier of 10 in high lamp (or even in low lamp), it would be way too dark.

Next, if you have a peak white of less than 100nits, you would indeed get much better results in SDR BT2020. This is something I've talked about already. In my opinion, if you get less than 100nits peak, you should simply forget about HDR, get your DI back and play everything in SDR BT2020 targeting your peak white (not 50nits as we used to).

One of the reasons for this is that as I explained earlier, there is no free lunch. As you lower the multiplier, the curve gets steeper. Yes, it gets you more brightness, but it desaturates the picture. If you had a x2 multiplier, you would have a brighter picture, but it would be black and white, which I'm sure negates a bit the point of HDR

Also one of the downsides of this is that you would have to start the roll-off super early, because you would be clipping at 200nits with a x2 multiplier (again using your 100nits actual peakY example), so you would have to start rolling off way before 50%. This is what the BT2390 curve does, to accommodate people with very dim set-ups (as low as 100nits peakY I guess), but that would produce and unwatchable picture and you would be leaving a lot of contrast on the table compared to an HDR picture. Your highlights would be super compressed.

Another downside is that the steeper the curve, the less control you have over shaping it because it's almost vertical. It means crunched blacks (unless you raise them out of target) and clipped highlights (unless you start rolling off very early, which means very little contrast in the part of the picture we want. We have less levels to play with, and I suspect we'd get a lot of banding. It would also be harder to see the data in Calman and make precise changes. With just a few control points to use for the curve itself (5 vs 9 as you would have to use at least 40% for the roll-off), your curve will be nothing like a PQ gamma curve. We only have 9 control points to start with anyway as there is nothing above 4000nits (90%), so both 90% and 95% are maxed out. This leaves us 5-80% to play with, but only 5-50% when clipping at 200nits (60% is 240nits, so will be maxed out too). 9 control points isn't much but works fine. 5 Control points isn't good enough to shape a precise enough curve.

I think the range to use is 800-1100nits for the target, maybe down to 600nits but lower than that I expect it to be pointless as it would be too desaturated.

All this is because unlike HD/Bluray which is mastered to 100nits peak white, we are dealing with content which is mastered to 1000nits-4000nits peak white.

What you suggest would therefore work great if we could get the Dolby Cinema version of the content. Mastered to 100nits (a perfect peak white for us in a dedicated room), it could use a x2 multplier and it would look AMAZING. Until people accept that the way the content is mastered makes a big difference with the way we can adapt it to our dedicated room, this misunderstsanding will remain.

Of course if you try a x2 multiplier and I'm wrong, please let us know, I'd like to hear how you can get good results with such a low multiplier.

Again, I reckon that if you can get around 100nits peak white or below, you should watch SDR BT2020. The picture will look much better: more contrast (a LOT more), better saturation, better black levels, etc. I target 100nits for my SDR BT2020 mode and it looks amazing, not blinding at all, like bluray does if I target 100nits. I do set the SDR conversion slider to -6 to resolve up to 1200nits (with the Panny contrast set to -2) though, which explains why. With the slider to the 0 default, I couldn't be able to do this, but the the panny clips content above 600nits, which is a bit too low to my taste.

There is a point for HDR displayed as HDR, but IMHO only if you can shoot up significantly above 100nits, at least with a custom curve such as the one we can produce today.

Quote:
Originally Posted by rak306 View Post
What a fantastic contribution to this thread!!!

THANK YOU Manni01!!!!


Out of curiosity, has anyone measured the gamma D curve with the JVC recommended settings, and compared to the PQ curve to see how they differ. (Yes I know, each situation is different, screen size, gain, throw.)

But it would be very informative for anyone who has done this to publish their results in either the form of "nits out vs nits in" or "nits out vs % video in".
You're welcome, I have posted these screenshots at the very beginning. I showed how pushing contrast in the JVC to raise brightness hurts the PQ curve, creating a bump in the high end which produces the harsh, over-contrasty picture that we should try to avoid at all cost

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Originally Posted by wse View Post
This thread is so technical that it's hard to follow, I know I stated this before but I wished they had a Calibration for dummies like me
It's called AV Science

You shouldn't embark in this if you don't have the underlying knowledge, and you don't have to. You can simply follow my recommendations for Gamma D, or you can hire a calibrator. Believe me, you don't want to spend the time learning this. I wish I hadn't .

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Originally Posted by rak306 View Post
Not Manni: but I asked a similar question a few days ago, and from Manni's reply, (if I understood him correctly) I believe the answer is he is not changing the curve before about the 75% point, which corresponds to ~1000 NITS, and by scaling by a factor of 5, he gets a real peak of 200 NITS @ 1000NIT input. But for 50% video (100 NIT input), he is still getting near 100 NIT output.

As far as gamma D (or any gamma) curve in the JVC RS500/600, it's a relative curve. This is because the peak lumens out (at 100% video) depends on how far you are from the screen, how big the picture is, and what your screen gain is.

Now what I think JVC should do, is have the user input his peak NIT output on screen. This could be either as measured from a meter, or estimated by the user. (JVC could provide a table of lumens out vs the ratio picture_width/throw_distance. The table would include both power settings and several bulb ages. This should be accurate to 20-40%. Then the user can calculate peak NIT on screen = 3.4*screen_gain* lumens /( (picture width**2) *9/16) ) , picture width in meters).

With the max NIT output on screen, the "gamma" curve becomes absolute. Then JVC should provide a proper PQ curve with some user controls (e.g when to start to deviate from the PQ curve). Of course I would not hold my breath, JVC has moved on from the RS600.

BT.2390 defines how to map PQ to a display of lesser peak output than 10k NITS, and who knows whether it looks good or not. Manni01 has suggested, that it starts to early for his taste. But FYI, when using the equations in BT.2390, for a maxLUM of 100NITs, at 100 NIT input you get 50 NIT output.
You got it right and your recommendations for the future are spot on. I kept mine realistic, because I want JVC to act on this for our models.

I don't NEED to roll off earlier, so I don't WANT to. I would leave a LOT of contrast on the table. Why would I want to do that?

Of course, others with dimmer set-ups should make their own curves to tune it to their needs, or get someonme to do it for them.

Quote:
Originally Posted by atabea View Post
Although the information posted here could seem intimidating, just remember you don't have to know EVERYTHING that's discussed. I certainly don't! If you just focus on a couple of items you will be at a great starting point;
1) learn the auto-cal procedure which, in practice, is not all that bad and
2) import one or two of Manni's custom gamma curves to your JVC.

The rest will come in time. Of course, hiring someone like ChadB will solve all your problems
Yes, that's a good compromise I highly recommend hiring someone like Chad B if one is not able to follow the discussion above. If one is, I wrote this and shared my curves to make it possible for some with compatible set-ups to get great results in their room. But my goal is not to deprive hard working, competent calibrators from getting paid to to the work they have learnt to do. Chad is a wonderful example, he is really dedicated to the JVCs, and he knows them inside out. He started using the JVC Autocal right away when he saw the potential instead of poo-pooing it because of the use of the Spyder, was on the multiplier as soon as he saw the potential. This is wonderful, I wish all calibrators were like him, and he deserves to reap the rewards for all this hard work

Quote:
Originally Posted by mbw23air View Post
He told me he can do HDR at low or high lamp but he says he gets better results at high lamp so I had him do HDR in high lamp. Im sure it will look great either way you choose.

Mike
I did more tests late last night and I do also prefer high lamp, for the reasons I mentioned earlier. You get better results and more control over the curve. The low end looks better, and you have more headroom for the highlights. I would use low lamp if I could, but with this custom curve I'd say got for max brightness (high lamp, iris fully open) if you can, and shape the curve from that if you can bear the fan noise/heat.

Quote:
Originally Posted by rollon1980 View Post
I actually agree with this. It doesn't leave a lot of headroom but it is likely the only way to ensure tone-mapping that's kind of faithful to the original. I mean by this analogy we should really map 100nits to 100nits straight and then tail off the rest of the curve to allow for some highlights. It likely wouldn't work very well, though, in creating the illusion of HDR. It would just be SDR with not much dynamic range in the highlights. Dolby Vision, where are you? :-/
Yes, Dolby Vision (or rather studios), where are you with content mastered to 100nits peak white, as for cinema... I honestly can't blame the industry for this choice. UHD Bluray is such a niche, we got lucky to have it at all with the rise of streaming. They couldn't have targetted our niche of a niche, they had to optimize for flat panels in a living room. We just have to make the most out of this non-optimized content. Playing with this, I also understand why DV might never happen for projectors (with consumer content) until we reach a
higher peak white. Too much compression of the dynamic range, too much desaturation. It looks great if we tune the curve to each set-up, but they need manufacturers to give them the means to achieve this reliably and consistently (i.e internal meter to measure actual peak white of the specific setup in an optimized, locked out mode).

Quote:
Originally Posted by danbez View Post
Is it recommended to do another AutoCal run after import the new custom Gamma curves? I just did an AutoCal a few weeks ago, but before Manni released those.
Not needed, just import the custom curve that better fits your needs.

Quote:
Originally Posted by COACH2369 View Post
Chad and I exchanged a few text messages today after reading about his findings in regards to a custom Gamma setting. He was just at my place two weeks ago, so I wanted to see if he would need to make adjustments on my system.

Based on my screen type, screen size and not wanting to have high lamp mode engaged he still thinks the SDR 2020 will be the better option for me. My projector is too close to me to have high lamp mode engaged.
I second this. If you can bear the fan noise and heat, high lamp is preferable, just like with 3D.

Quote:
Originally Posted by zombie10k View Post
it's not necessary as it calibrates all gamma modes, try importing the curve and running the A/B comparison between Gamma D and custom 3, it won't be hard to know which one is which.

for those with the Panasonic UB900, if you pause for extended periods of time I have seen the JVC switch back to Gamma D. keep an eye on this during testing.
Yes I had mentioned this earlier, a long pause causes a return to Gamma D. That's why I would like to be able to find a working IP code for custom gamma. I want to program iRule to send the custom1 gamma code before or after I press play on my UHD Bluray screen.

Quote:
Originally Posted by claw View Post
I imported two low lamp gammas; 140-1000-4000 and 140-1000-1000.

140-1000-4000 worked really well for the 4000 nit Fury Road. Two other 4000 nit discs; Jupiter and Pacific Rim, while better than I could previously get in HDR, were still darker than I would like. Just as Manni had suggested we would find if we had a larger screen than his.

After using both the black and the white clipping patters for the 140-1000-1000 gamma, I preferred it over the 4000 nit gamma when viewing 1000 nit discs. I got just a bit more brightness with it. It worked really well with Lucy. A darker 1000 nit disc, John Wick, was still darker than I would like, as I expected.
This is why I released the no roll-off versions, with warning, so people can select them to eek more perf out of titles mastered to 1000nits. The downside is the clipping of the details with 4000nits titles (or even the 1100nits titles), so I wouldn't use that curve on its own.

If this is still too dark (which isn't only a function of the screen size, the gain also plays a large part, see the good results Zombie10K gets on his 142" diag screen with a 2.8 gain), you need a custom curve with a lower multiplier, or you need to replace your screen with a smaller/higher gain one. This is to be expected.

Quote:
Originally Posted by zombie10k View Post
my 2.8HP @ 142" has a big impact on the overall HDR presentation. brightness wasn't the issue in my setup, it was the terrible overall tone of Gamma D. overcooked highlights, weak mid-range, poor shadow details. so many attempts to get it right but Gamma D was the bottleneck.

now the tone is much more even across the image and bright enough where i can clamp the iris down quite a bit in high lamp or run low close to wide open.
Glad the new curves also work for you

Quote:
Originally Posted by stevenjw View Post
That's exactly what I was thinking. AVS along with other JVC dealers and reviewers that definitely read this thread (you know who your are).

These are the folk that can get the ear of JVC better than our rants/wishes in this thread. Manni's list is pretty much complete, but I'd settle for no. 1 (working DI fade2black in HDR) and either no. 3 (allow selective Gamma choice setting for HDR instead of GammaD default) or no. 4 (individual IR codes for Gamma settings). If we got no. 3, we wouldn't even need no. 4 really. No. 2 is a nice to have improvement for GammaD, but with custom gamma curves, is no longer that important IMHO. No. 1 and no. 3 would be good enough for me.
We would still need #4 because it's not's OK to not have working IP codes for custom gamma. They are in the control guide, they just don't work. We need to know why and fix this, not only for us, for all the future models. Also it would be nice for geeks to have a 4000nits, 1100nits and 1000nits button in iRule to select the optimized curve for each title and eek the last bit of performance from the PJ. It's not necessary (the 4000nits curves are not significantly dimmer overall) but it's a nice way to get the best contrast/brightness you can get for each title if you can live with the hassle.

#3 is the most immediate, most needed change. It would be very easy to implement, so no excuse for them not to deliver this at a minimum to make up for #2 , which really should also be corrected. It's a HUGE bug. Not everyone can make their own curve or hire a calibrator to make one for them. We should be able to approximate it with Gamma D without killing our on/off. Gamma D is a bit more saturated that custom curves, so some might prefer that option as long as it doesn't raise the black floor and can resolve the low end.
mbw23air, stevenjw, Chad B and 1 others like this.

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I need some advise on setting up my PJ for calibration with CalMan.
From what I see in the menu system of the projector, only 2-point color temperature calibraion is possible. Is there any way to calibrate for 10 or more points?
Does CalMan support JVC internal pattern generator? I saw that it is possible for other model in their guide, but our models are not mentioned.
Any other adivse on CalMan calibration?
I have C6 meter and Enthusiast license. My projector is 7000 model.

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post #20806 of 31987 Old 02-14-2017, 04:55 AM
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Quote:
Originally Posted by wse View Post
This thread is so technical that it's hard to follow, I know I stated this before but I wished they had a Calibration for dummies like me
There's this one:
http://www.curtpalme.com/forum/viewtopic.php?t=10457

Quote:
Originally Posted by Manni01 View Post
As I said, the multiplier is related to the peak brightness you use. If you use high lamp, you can use a lower multiplier than in low lamp.

For example, to target 1000nits, I use a multiplier of 5 in high lamp and of 7 in low lamp. I would never use a multiplier of 10 in high lamp (or even in low lamp), it would be way too dark.
But if you use a multiplier of 5, everything will be 1/5 as bright as it should be, 100 nits will end up being 20 nits, 50 nits -> 5, etc, etc.

With an SDR (think Blu-ray), 100 nit content in the source will be 50 nits on screen. 50 nits -> 25 etc.

Quote:
Next, if you have a peak white of less than 100nits, you would indeed get much better results in SDR BT2020. This is something I've talked about already. In my opinion, if you get less than 100nits peak, you should simply forget about HDR, get your DI back and play everything in SDR BT2020 targeting your peak white (not 50nits as we used to).
FWIW, I've got headroom to open my iris and get over 100nits, I just didn't mess with that in the limited time I had.

Quote:
One of the reasons for this is that as I explained earlier, there is no free lunch. As you lower the multiplier, the curve gets steeper. Yes, it gets you more brightness, but it desaturates the picture. If you had a x2 multiplier, you would have a brighter picture, but it would be black and white, which I'm sure negates a bit the point of HDR

Also one of the downsides of this is that you would have to start the roll-off super early, because you would be clipping at 200nits with a x2 multiplier (again using your 100nits actual peakY example), so you would have to start rolling off way before 50%. This is what the BT2390 curve does, to accommodate people with very dim set-ups (as low as 100nits peakY I guess), but that would produce and unwatchable picture and you would be leaving a lot of contrast on the table compared to an HDR picture. Your highlights would be super compressed.

Another downside is that the steeper the curve, the less control you have over shaping it because it's almost vertical. It means crunched blacks (unless you raise them out of target) and clipped highlights (unless you start rolling off very early, which means very little contrast in the part of the picture we want. We have less levels to play with, and I suspect we'd get a lot of banding. It would also be harder to see the data in Calman and make precise changes. With just a few control points to use for the curve itself (5 vs 9 as you would have to use at least 40% for the roll-off), your curve will be nothing like a PQ gamma curve. We only have 9 control points to start with anyway as there is nothing above 4000nits (90%), so both 90% and 95% are maxed out. This leaves us 5-80% to play with, but only 5-50% when clipping at 200nits (60% is 240nits, so will be maxed out too). 9 control points isn't much but works fine. 5 Control points isn't good enough to shape a precise enough curve.

I think the range to use is 800-1100nits for the target, maybe down to 600nits but lower than that I expect it to be pointless as it would be too desaturated.

All this is because unlike HD/Bluray which is mastered to 100nits peak white, we are dealing with content which is mastered to 1000nits-4000nits peak white.

What you suggest would therefore work great if we could get the Dolby Cinema version of the content. Mastered to 100nits (a perfect peak white for us in a dedicated room), it could use a x2 multplier and it would look AMAZING. Until people accept that the way the content is mastered makes a big difference with the way we can adapt it to our dedicated room, this misunderstsanding will remain.

Of course if you try a x2 multiplier and I'm wrong, please let us know, I'd like to hear how you can get good results with such a low multiplier.
I'll definitely give it a shot, because while I trust your experience, I just can't correlate what you're saying with what I'm thinking of. Specifically, I'm thinking that if we target a 50% baseline, we've got 0-50nits for all the normal content, which should work/look fine, and then all of 50-100 nits for rolling off the highlights.

Even then, I think feeding raw HDR to my RS600 is dead to me, when I was messing around the other night I threw in ST Beyond, and the black level is something like 100x higher in HDR mode than SDR WCG mode (which I have calibrated to like 25fL). But I'm curious if I can get a good "PQ" curve setup, first just to see if it's possible, and second for those sources that don't support HDR->SDR Dynamic Range Conversion well, or at all (like Amazon/Netflix). I hate to leave quality on the table.

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post #20807 of 31987 Old 02-14-2017, 05:16 AM
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Explanation of PQ Gamma

Quote:
Originally Posted by stanger89 View Post
There's this one:
http://www.curtpalme.com/forum/viewtopic.php?t=10457



But if you use a multiplier of 5, everything will be 1/5 as bright as it should be, 100 nits will end up being 20 nits, 50 nits -> 5, etc, etc.

With an SDR (think Blu-ray), 100 nit content in the source will be 50 nits on screen. 50 nits -> 25 etc.



FWIW, I've got headroom to open my iris and get over 100nits, I just didn't mess with that in the limited time I had.



I'll definitely give it a shot, because while I trust your experience, I just can't correlate what you're saying with what I'm thinking of. Even then, I think feeding raw HDR to my RS600 is dead to me, when I was messing around the other night I threw in ST Beyond, and the black level is something like 100x higher in HDR mode than SDR WCG mode (which I have calibrated to like 25fL). But I'm curious if I can get a good "PQ" curve setup, first just to see if it's possible, and second for those sources that don't support HDR->SDR Dynamic Range Conversion well, or at all (like Amazon/Netflix). I hate to leave quality on the table.
The PQ curve isn't linear. I use a multiplier of 5 or 6 in high lamp because I have 200nits to play with and targeting around 1000-1200nits gives the best results in my setup. I never said people with dimmer setups should use such multipliers, I just simply wouldn't recommend targeting significantly lower than 600-800nits, for all the reasons I indicated above.

When using a multiplier of 5 in high lamp targeting 1000nits, when content is at 100nits (50% stim in PQ) it is displayed at 100nits (50% of 200nits, which is my actual peakY). You just don't understand how PQ scales, that's why your logic doesn't work with PQ.

You are confusing the multiplier, which is the way we scale the data in the software so it becomes readable, with the way to convert nits in PQ to actual nits. Because PQ isn't linear, you can't simply divide the nits in content by the multiplier to get the output nits.

You need to look at the nits in content ("in" stim), the % in PQ it corresponds to in the non-linear PQ curve ("PQ Stim", and divide the actual peakY by this PQ stim to see how much nits you are actually outputting ("out" stim).

In PQ, 50% stim is 100nits, 60% is 240nits, 70% is around 800nits, 75% is 1000nits, 80% is around 1200nits, 90% is 4000nits.

If you clip below 800nits (70%), you lose the 70% control point. and have to start rolling off at 60% (240nits).

If you clip below 240nits (60%), you lose the 60% control point and you have to start rolling off at 50% (100nits). This is why you will either clip a lot of content or LOSE contrast on the part of the picture that matters most, i.e. 0-100nits. You don't want to clip anything there.

Hence my recommendation not to target less than 800nits or so if at all possible, so that you don't lose the 70% point.

An in any case, do not target below 240nits, or you will lost the 60% control point. The closer to 240nits, the more compressed your highlights will be, so you'll have very for levels to show the gradations.

Yes, you'll get HDR as bright as SDR, but you'll have no highlights, so again, what the point exactly? Plus the picture will be completely undersaturated, as the more you raise brightness that way, the more you lose saturation. This is why if you can, a curve with a target of 1000-1100nits is best.

You need to understand this to understand why your plan won't work. Please re-read my explanation above with this in mind, you will understand why an almost vertical curve clipping at 200nits forcing you to start rolling off at 40% or less, hence below 100nits will lead to an unwatchable picture, completely desaturated, with a lot less contrast in the most important range (0-100nits).

Again, I haven't tried, so please try and post your results here if they are good. I could absolutely be wrong

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post #20808 of 31987 Old 02-14-2017, 05:58 AM
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JVC recommends 4K HDR Gammas at PT12. End of.

Quote:
Originally Posted by Manni01 View Post
Whatever you ask them, please do not tell them that we need different curves for different titles, this is not true and will confuse them, which will slow down progress. It's the target that counts, not the roll-off.

You can have a curve that is as bright for all titles and plays them all without any clipping.

The brightness used to calibrate the curve doesn't matter either. I'll explain more later today, but the curve I created in low lamp (peakY 140nits) is LESS bright than the curve I created in high lamp (peakY200nits), because the target is higher (1100nits vs 1000nits).

So what you need to make the curve brighter is a lower multiplier, NOT a lower clipping point. That's taken of by the roll-off, which is separate from the target.

I'll explain more later today and if you download the new curves and try them you'll see the difference and you will understand that the two are not connected.

All your curves are based on Spectral's flat panel EOTF, not a projector EOTF. That's why PT=5 for MCust1 ... flat panel HDR TV's don't need the JVC brighter Gamma of PT12 ... flat panels have plenty of light so the PT is much lower (PT5). The flat panels are high luminance displays ... beyond the reach our of our projector bulbs ... unless one has a tweaked rig ... meaning those with a screen that is the size of a postage stamp or a larger HP screen with a gain of 2.4++. These tweaked out projector rigs are really flat panel rigs and these rigs can use the flat panel EOTF ... this is not what 95% of us have ... we have normal projector rigs.


The good news is JVC understands HDR projector gammas! Great news! JVC want's their projectors to be at PT12. Even flat panel projector rigs can benefit. This is Carbon's ETOF curve @ PT12+, based on your GammaD ETOF sweep. Can you help me to perfect it? This new Carbon Curve can be wave shaped verified to my existing GammaD Bright Curve at PT12 or any other PT value to confirm enough/too_much brightness at MTO and Specular levels. This curve should be good for 100nit rigs.



Pic1. 4K HDR Projector ETOF @ PT12 Gamma Brightness. cfp 021417
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post #20809 of 31987 Old 02-14-2017, 06:01 AM
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Quote:
Originally Posted by Manni01 View Post
The PQ curve isn't linear. I use a multiplier of 5 or 6 in high lamp because I have 200nits to play with and targeting around 1000-1200nits gives the best results in my setup. I never said people with dimmer setups should use such multipliers, I just simply wouldn't recommend targeting significantly lower than 600-800nits, for all the reasons I indicated above.

When using a multiplier of 5 in high lamp targeting 1000nits, when content is at 100nits (50% stim in PQ) it is displayed at 100nits (50% of 200nits, which is my actual peakY). You just don't understand how PQ scales, that's why your logic doesn't work with PQ.

You are confusing the multiplier, which is the way we scale the data in the software so it becomes readable, with the way to convert nits in PQ to actual nits. Because PQ isn't linear, you can't simply divide the nits in content by the multiplier to get the output nits.

You need to look at the nits in content ("in" stim), the % in PQ it corresponds to in the non-linear PQ curve ("PQ Stim", and divide the actual peakY by this PQ stim to see how much nits you are actually outputting ("out" stim).

In PQ, 50% stim is 100nits, 60% is 240nits, 70% is around 800nits, 75% is 1000nits, 80% is around 1200nits, 90% is 4000nits.
Yup, understood... However...

So you put up the 50% pattern in Calman, that represents 100 nit content, Calman thus expects your meter to read 100 nits. If you use a 5x multiplier, and adjust the projector's curve so that Calman shows 100 nits, that means that the meter is actually reading 100/5 or 20 nits.

Quote:
If you clip below 800nits (70%), you lose the 70% control point. and have to start rolling off at 60% (240nits).

If you clip below 240nits (60%), you lose the 60% control point and you have to start rolling off at 50% (100nits). This is why you will either clip a lot of content or LOSE contrast on the part of the picture that matters most, i.e. 0-100nits. You don't want to clip anything there.

Hence my recommendation not to target less than 800nits or so if at all possible, so that you don't lose the 70% point.
I'm not talking about clipping below 1200 nits.

With a normal PQ curve you should have this (if I put the formula into excel correctly):
10% - 0.32 nits
20% - 2.43 nits
30% - 10.0 nits
40% - 32.5 nits
50% - 92.3 nits
60% - 224 nits
70% - 621 nits
80% - 1555 nits
90% - 3905 nits
100% - 10000 nits

What I'm picturing is something more like this:
10% - 0.16 nits
20% - 1.21 nits
30% - 5.02 nits
40% - 16.2 nits
50% - 46.1 nits
60% - 65 nits - start the roll of (these are just made up)
70% - 80 nits
80% - 90 nits
90% - 95 nits
100% - 100 nits



Here's a comparison (non logarithmic) of a 2x vs 5x multiplier:



Quote:
An in any case, do not target below 240nits, or you will lost the 60% control point. The closer to 240nits, the more compressed your highlights will be, so you'll have very for levels to show the gradations.

Yes, you'll get HDR as bright as SDR, but you'll have no highlights, so again, what the point exactly? Plus the picture will be completely undersaturated, as the more you raise brightness that way, the more you lose saturation. This is why if you can, a curve with a target of 1000-1100nits is best.

You need to understand this to understand why your plan won't work. Please re-read my explanation above with this in mind, you will understand why an almost vertical curve clipping at 200nits forcing you to start rolling off at 40% or less, hence below 100nits will lead to an unwatchable picture, completely desaturated, with a lot less contrast in the most important range (0-100nits).

Again, I haven't tried, so please try and post your results here if they are good. I could absolutely be wrong
I haven't either, nor have I had a chance to try your custom curve, but I do plan to do both


-edit

I've added examples of 5x multiplier to the graphs.
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Last edited by stanger89; 02-14-2017 at 06:48 AM. Reason: Added pictures for 5x multiplier
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Quote:
Originally Posted by Carbon Ft Print View Post
All your curves are based on Spectral's flat panel EOTF, not a projector EOTF. The flat panel EOTF is based on very high luminance displays ... beyond the reach our of our projector bulbs ... unless one has a tweaked rig ... those with a screen that is the size of a postage stamp or a larger HP screen with a gain of 2.4++. These tweaked out projector rigs are really flat panel rigs, not what 95% of use have. We have projector rigs.


The good news is JVC understands HDR projector gammas! Great news! JVC want's their projectors to be at PT12. Even flat panel projector rigs can benefit. This is Carbon's ETOF curve @ PT12+, based on your GammaD gamma sweep, to be used for 4K HDR JVC projectors. Can you help me to perfect it? This new Carbon Curve can be wave shaped verified to my existing GammaD Bright Curve at PT12 or any other PT value to confirm enough/too_much brightness at MTO and Specular levels.



Pic1. 4K HDR Projector ETOF @ PT12 Gamma Brightness. cfp 021417
You don't undestand the use of the multiplier. It is because Calman's EOTF is made for flat panels that we have to use a multiplier to use the workflows, tricking them into thinking we are calibrating a flat panel (600-1100nits). We wouldn't need a multiplier otherwise, but on the other hand they have no idea which peakY each setup reaches, so they can't provide a PJ workflow, they have no idea what the EOTF should be for projector setups because there is too much variations and each manufacturer is doing their own thing.

You are trying to get JVC to priviledge setups which make little to no benefit from HDR so that it fits YOUR needs better, it makes no sense whatsoever. There is no perfect EOTF curve. There is one for you, with your crazy contrast settings, but that's not the ideal one for anyone else. If you want an ideal gamma curve, just follow my procedure and make it instead of trying to get the world to revolve around your setup, which doesn't have enough brightness to benefit from HDR and should be running in SDR BT2020.

Anyway, I'm done trying to explain this, I'll leave it there for others to use, debate and discuss.

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post #20811 of 31987 Old 02-14-2017, 06:32 AM
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Quote:
Originally Posted by Manni01 View Post
You don't undestand the use of the multiplier. It is because Calman's EOTF is made for flat panels that we have to use a multiplier to use the workflows, tricking them into thinking we are calibrating a flat panel (600-1100nits). We wouldn't need a multiplier otherwise, but on the other hand they have no idea which peakY each setup reaches, so they can't provide a PJ workflow, they have no idea what the EOTF should be for projector setups because there is too much variations and each manufacturer is doing their own thing.

You are trying to get JVC to priviledge setups which make little to no benefit from HDR so that it fits YOUR needs better, it makes no sense whatsoever. There is no perfect EOTF curve. There is one for you, with your crazy contrast settings, but that's not the ideal one for anyone else. If you want an ideal gamma curve, just follow my procedure and make it instead of trying to get the world to revolve around your setup, which doesn't have enough brightness to benefit from HDR and should be running in SDR BT2020.

Anyway, I'm done trying to explain this, I'll leave it there for others to use, debate and discuss.


This multiplier should be brightening the gamma curve ... shifting the curve to the left. MCust1's HDR gamma was too low (PT5). If there is a new gamma to try out, I'll do a profile run and tell you how close to PT12 the curve is ... it should be around JVC's PT12 recommendation ... higher would be better for 100nit rigs.


Edit: Brightening the JVC projector picture should be done by both decreasing gamma and increasing CR. JVC knows this and it is reflected in their PT12 recommendation for 100" screens. JVC recommends using higher PT values (which decreases gamma ... and by doing so increases the brightness of the picture) for larger screens. This Y screen multiplier (x,y, Y) seems to be just a CR curve adjustment ... which just makes the GammaD slope steeper (increasing CR of the curve makes the gamma slope steeper). If the screen multiplier does decrease gamma (like going from 2.4 to 2.2 in SDR), this will be noted by a slight gamma shift to the left. I'll do a profile run on your next curve to confirm; otherwise, we'll need to shift the flat panel EOTF curve up in calMAN to decrease gamma which will make the picture brighter. That' my plan.


Edit2: In fact, any significant roll off may decrease brightness below Y50% ... the MTO levels ... because the upper half of the curve (specular portion) is being weakened by the roll off. I've seen this happen with my custom gamma curves. I'll check your next custom GammaD curve for before and after Y10%, Y20%, Y30%, Y40% and Y50% nit readings to see if this area of the curve is being brightened with roll off. Hopefully so. Remember, the most important part of the curve to get right is the MTO levels for projects... those luminance levels under 50% ... that's where all the dark issues are at ... the specular levels are fine ... so avoid weakening the specular levels.

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Originally Posted by zombie10k View Post

for those with the Panasonic UB900, if you pause for extended periods of time I have seen the JVC switch back to Gamma D. keep an eye on this during testing.
I have seen this happen with the Oppo too, so might be a JVC thing. Either way, Gamma should always the last thing we check before watching a movie.
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post #20813 of 31987 Old 02-14-2017, 07:22 AM
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My initial results with the custom gamma curve were positive but certainly not as dramatic as others have described. However, I am new at this and still have a lot to learn. Furthermore, my HDR source is a streaming box (nVidia Shield), not a UHD player. The shield plays certain Netflix and Amazon Video shows in HDR (e.g. Marco Polo, Daredevil, etc.) and can also play the Masciola patterns. I have a 100" 0.9 gain screen in a dark room and I am using wide open iris on low lamp.

Mostly I am looking to improve the shadow detail which is quite inadequate with Gamma D. What I experience after importing the gamma curve is a slight improvement in that shadow detail with less impact on the black floor. In my case I need to adjust BR to +18 in the JVC (the player offers no BR adjustment) to barely resolve two bars above reference black in the Masciola pattern. Even at that point there is certainly a visually detectable raising of the black floor when I put on a 0% pattern and compare that with Hide button. As a comparison, with Gamma D (+10/+5/+5) I also need to raise BR to +18 however the floor seems raised more when doing on/off than with the custom curve.

The shadow detail seems slightly improved with the custom gamma, but I wouldn't use the word dramatic to describe it. I understand that this may be due to my setup and I am willing to spend some time and money to get better, or at least learn something in the process, and perhaps my results may also help someone else.

So here are some questions I have for next steps:

1. Sounds like measuring Ypeak may help to see if the curve may or may not be applicable for my setup. Currently I have a Spyder 5 that I have used for autocal. Can I measure my Ypeak using the Spyder 5 or do I need to get a light meter to measure that?

2. I am considering getting CalMAN and learning how to create a curve for my use trying different multipliers. I don't want to spend thousands on Ultimate--can this be done with CalMAN Enthusiast? (I also need a new probe, see next question)

3. Is the i1Display PRO an adequate meter for this? I would like to spend no more than $300 or so on a meter at this time.
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post #20814 of 31987 Old 02-14-2017, 07:33 AM
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Originally Posted by Manni01 View Post
Yes, that's a good compromise I highly recommend hiring someone like Chad B if one is not able to follow the discussion above. If one is, I wrote this and shared my curves to make it possible for some with compatible set-ups to get great results in their room. But my goal is not to deprive hard working, competent calibrators from getting paid to to the work they have learnt to do. Chad is a wonderful example, he is really dedicated to the JVCs, and he knows them inside out. He started using the JVC Autocal right away when he saw the potential instead of poo-pooing it because of the use of the Spyder, was on the multiplier as soon as he saw the potential. This is wonderful, I wish all calibrators were like him, and he deserves to reap the rewards for all this hard work
.....And that is why ChadB is unique among calibrators. I reached out to two well-known calibrators up here in Canada and asked if they would do a custom (multiplier) curve using the JVC software. One flat out refused saying it would be a waste of time, while the other admitted he didn't know anything about this concept, but was willing to learn more about it. He did ultimately say that I should stick with Gamma D though. So, for now, am sticking with Manni's custom curves while I figure out how to do one for myself.......Or, ChadB could do a really long road trip
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post #20815 of 31987 Old 02-14-2017, 07:57 AM
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Originally Posted by stanger89 View Post
Yup, understood... However...

So you put up the 50% pattern in Calman, that represents 100 nit content, Calman thus expects your meter to read 100 nits. If you use a 5x multiplier, and adjust the projector's curve so that Calman shows 100 nits, that means that the meter is actually reading 100/5 or 20 nits.

I'm not talking about clipping below 1200 nits.

With a normal PQ curve you should have this (if I put the formula into excel correctly):
10% - 0.32 nits
20% - 2.43 nits
30% - 10.0 nits
40% - 32.5 nits
50% - 92.3 nits
60% - 224 nits
70% - 621 nits
80% - 1555 nits
90% - 3905 nits
100% - 10000 nits

What I'm picturing is something more like this:
10% - 0.16 nits
20% - 1.21 nits
30% - 5.02 nits
40% - 16.2 nits
50% - 46.1 nits
60% - 65 nits - start the roll of (these are just made up)
70% - 80 nits
80% - 90 nits
90% - 95 nits
100% - 100 nits



Here's a comparison (non logarithmic) of a 2x vs 5x multiplier:



I haven't either, nor have I had a chance to try your custom curve, but I do plan to do both


-edit

I've added examples of 5x multiplier to the graphs.
Quote:
Originally Posted by Carbon Ft Print View Post
This multiplier should be brightening the gamma curve ... shifting the curve to the left. MCust1's HDR gamma was too low (PT5). If there is a new gamma to try out, I'll do a profile run and tell you how close to PT12 the curve is ... it should be around JVC's PT12 recommendation ... higher would be better for 100nit rigs.


Edit: Brightening the JVC projector picture should be done by both decreasing gamma and increasing CR. JVC knows this and it is reflected in their PT12 recommendation for 100" screens. JVC recommends using higher PT values (which decreases gamma ... and by doing so increases the brightness of the picture) for larger screens. This Y screen multiplier (x,y, Y) seems to be just a CR curve adjustment ... which just makes the GammaD slope steeper (increasing CR of the curve makes the gamma slope steeper). If the screen multiplier does decrease gamma (like going from 2.4 to 2.2 in SDR), this will be noted by a slight gamma shift to the left. I'll do a profile run on your next curve to confirm; otherwise, we'll need to shift the flat panel EOTF curve up in calMAN to decrease gamma which will make the picture brighter. That' my plan.


Edit2: In fact, any significant roll off may decrease brightness below Y50% ... the MTO levels ... because the upper half of the curve (specular portion) is being weakened by the roll off. I've seen this happen with my custom gamma curves. I'll check your next custom GammaD curve for before and after Y10%, Y20%, Y30%, Y40% and Y50% nit readings to see if this area of the curve is being brightened with roll off. Hopefully so. Remember, the most important part of the curve to get right is the MTO levels for projects... those luminance levels under 50% ... that's where all the dark issues are at ... the specular levels are fine ... so avoid weakening the specular levels.
Guys, do me a favor, get your fingers out, and follow the method to do your own curve.

When you have, let's see and discuss your results.

Carbon, I really do not see why I should pay any attention to the way you measure my curve in your setup. You have a different player, different brightness/contrast settings, a different screen with different gain, and not enough brightness to play HDR.

Why on earth should the way you measure MY curves made for MY setup be any useful? Yes, my curves do not fit your needs. That's because I make them for myself and share them as well as the method so you can make your own.

At least make your own curve (I would strongly suggest resetting all these brightness and contradt settings in both the player and the PJ when doing so) and THEN tell us what you measure.

I still recommend targeting no lower than 600-800nits following the Calman workflow and my procedure.

Feel free to contribute with your curves and procedure once you have something that works.

But please stop bugging me to provide curves that works better for people who shouldn't be using HDR anyway because they have the wrong screen...

Until you guys come up with your own curves and share them for others to try (and I'm sure that if they work for you they will help others), I'm not discussing this further.
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post #20816 of 31987 Old 02-14-2017, 08:05 AM
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Originally Posted by atabea View Post
.....And that is why ChadB is unique among calibrators. I reached out to two well-known calibrators up here in Canada and asked if they would do a custom (multiplier) curve using the JVC software. One flat out refused saying it would be a waste of time, while the other admitted he didn't know anything about this concept, but was willing to learn more about it. He did ultimately say that I should stick with Gamma D though. So, for now, am sticking with Manni's custom curves while I figure out how to do one for myself.......Or, ChadB could do a really long road trip

That is another thing I have always respected about Chad having been my calibrator since 2005 going back to my former RPTV days. He doesn't have a big ego that interferes with the truth and latest information. He stays atop of everything to give the best result for the customer and will spend however much time is required on that display/projector.
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post #20817 of 31987 Old 02-14-2017, 09:14 AM
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Originally Posted by Manni01 View Post
Guys, do me a favor, get your fingers out, and follow the method to do your own curve.

...

At least make your own curve (I would strongly suggest resetting all these brightness and contradt settings in both the player and the PJ when doing so) and THEN tell us what you measure.

...

Feel free to contribute with your curves and procedure once you have something that works.

But please stop bugging me to provide curves that works better for people who shouldn't be using HDR anyway because they have the wrong screen...
I absolutely will make my own curve, I just haven't had the free time to do it yet. And also I'm not asking you to make a curve for me, I am simply discussing the theory of making such curves. Specifically what the target of that curve should be.

Taking a step back from the practical limitations that may exist in the JVC projectors. Do you disagree that an "ideal" mapping of HDR for a projection setup (which can nit 100nits+) should have 100 nit content displayed at 50 nits or so? And if so, what should it be and why?
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post #20818 of 31987 Old 02-14-2017, 09:29 AM
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Originally Posted by Mojito View Post
I need some advise on setting up my PJ for calibration with CalMan.
From what I see in the menu system of the projector, only 2-point color temperature calibraion is possible. Is there any way to calibrate for 10 or more points?
Does CalMan support JVC internal pattern generator? I saw that it is possible for other model in their guide, but our models are not mentioned.
Any other adivse on CalMan calibration?
I have C6 meter and Enthusiast license. My projector is 7000 model.
I have the same meter and software. It doesn't support the internal patterns. The RS45/55 series was the last. All I could use was the 2-pt but I am by no means professional. I use a Lumagen 2020 for my pattern generator. You can use Amazon Fire TV as a pattern generator. Calman can control that after downloading the app.
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post #20819 of 31987 Old 02-14-2017, 10:34 AM
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Originally Posted by Manni01 View Post
Anyway, I'm done trying to explain this, I'll leave it there for others to use, debate and discuss.
Just do the rest of us a big favor and NOT leave this thread. Use the ignore function or whatever it takes for you to stick around.

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post #20820 of 31987 Old 02-14-2017, 10:54 AM
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Originally Posted by stanger89 View Post
Thank you fabulous guide this is the new link http://www.curtpalme.com/forum/viewtopic.php?t=35322


Too bad it it require purchasing software and equipment I have an RS600 that has Auto calibration?

I already bought Datacolor Spyder 5 so spending an other $500 for Chromapure is out of my budget
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