Christie's VDR verses Barco's light steering

[Alan Gouger]

Both technologies were shown at CinemaCon. Looks like Christies VDR works with all content, no need for dedicated authored content. The Barco light steering like Dolby vision does require dedicated authored content. Did anyone see the demos at CinemaCon, what are your thoughts. There are videos online of each demo, they are long but both have technical breakdowns of what they are doing if you have the time to watch through them. Looks like Christies VDR is a software update, no mention of cost. This may end up the more popular verses light steering. Both technologies seam to target HDR but it appears standard DCI content will benefit from Christies VDR. Dolby Vision has a new generation projector as well.
Christies vdr: https://youtu.be/XGtUDV5yvj0?si=SG2_oRy8ZsenUdKo
Barco: https://youtu.be/64AvGq3TEJI?si=KcrAqfRZhmVjICFT

[Steve Guttag]

I wouldn't categorize it as you have. VDR doesn't need/want dedicated content for "standard" mode. It's "trick" is that it modulates the light. So, the lasers are only as bright as the brightest point on the screen needs. So, 14fL is 14fL. However, if the brightest point is just 10fL, then, it can lower laser level down some. That has the potential advantage of lowering the black levels. What I think its biggest benefit will be is in laser life by only driving them at power when they are needed (sort of like a night set-back on your thermostat except it actively monitors the image). This sort of technology would make me much more comfortable specing a projector that starts its life at over 50% laser power because if you start it at 60-70%...with VDR...you probably would be back to 50% on average.

In performance mode, VDR also requires properly mastered content because you are trying to go for 108 or 300 nits. Without content mastered for it, you'll over saturate your colors and get the same nasty effect that running HDR on your TV with non-HDR content.

Barco's light steering is a different approach to light optimization. By recognizing that you are not outputting full white at all points of the screen at all times, you can optimize where the light goes. Barco is going for the 300nit DCI standard with that system. The downside there is that it artificially constricts the projector's maximum size. With a low-gain screen (1.0 - 1.3), if you want 300nits, you are going to be down in the 35-foot wide screen range or going for multi-projector, or worse, higher-gain screen. My observations of the LS projector have been is that it is like their HC projectors in terms of black levels. It's better than stock (3-times better) but it isn't really black. I think they would be better served by going for 108Nits (or thereabouts), which would double the normal white point and allow their black levels to get much closer to deep backs until such time as 300nits shows that it has mass appeal. It's great that DCI wants to get a lofty goal but it has no more proof that it will be a lasting format than 3D or HFR.

Then there is Dolby Vision. 108 Nits with the best black level of them all...by a pretty fair margin. In the Dolby booth, they were showing (though not operating) their new Dolby Vision projector (made and looks like a Christie Cinelife + with extra length.

In terms of appearance, there really isn't a close call on projection, Dolby Vision has the overall dynamic range and it has a track record.

As for the other two, I think that Christie's VDR will get some acceptance, if not standard for the standard mode as it seems to have only benefits and no tradeoffs. We'll see how it does with real HDR content. Remember, its trick is modulating the light. If you put up a 50% checkerboard pattern, it can't do anything with that...it has to be at full brightness to cover the white squares. So, how it performs with real content will likely depend on the content itself. it is like Perspecta stereo...at the end of day, it is just mono. VDR is just the one light source.

Barco sort of has to depend on 300Nit content and for people to accept its black levels as good enough.

The other reality is that LED screens are barking at the gates. They'll be able to handle 300nits without any issue on deep blacks too. It would appear that sound transmission is being worked on too and now by multiple manufacturers. They keep getting better and the price should keep getting better. There will come a time when people won't be putting in projectors.

[James Gardiner]

Thanks for the feedback for those who could not get to CinemaCon.

I personally think, producing content that actually fit into the DCI-HDR adendum (standard) are the key. It means anyone can make content at any post house with minimal extra costs. Its just another grade pass down from the Streaming full HDR master as required by all streaming services.

Black levels are an issue, but more than not, "Are they really?". When you see places like EVERYMAN, produce some amazingly bright and attractive seating and walls in their theatres, being part of their signature experience.... The Black levels are not going to work that well anyway.

Historically, advancements and wide acceptance are driven by standards. It's why SMPTE exists. It's why 35mm film took over. Barco-LS has archived DCI-HDR-addendum requirements. That's now the expected going forward. All these 108nit solutions are bespoke implementations. If the default has caught up. Unless they have some significantly better features that the consumer will defiantly notice. They will eventually fall away or grow to also meet the DCI-HDR-addendum.

LED walls are definitely interesting, but I cannot see costs i.e. weight and physical installations costs (theatre floor reinforcement), Power consumption, basic fact you are buying something that is 10 times in physical equipment size of a projector and the costs associated, or the audio transparency issue ever being competitive to traditional perforated screens. But they will have their place. Especially in experiences where more ambient light is required.

[Mike Babb]

Barco hiring Stuart Bowling could be a serious factor, he was promoting Vision and Atmos with the creatives in Hollywood. Personally I think content availability will determine which method "wins".
300 nits vs 108 vs whatever else is proposed is certainly not apples to apples.

[Stefan Scholz]

WE have to keep in mind, the 50 candles/nits (14fl) standard is the border to night vision. Human eyes are not in full color mode. It was chosen initially, as the first digital implementation had extremely bad black levels, and this compromise was chosen for that. In film projection the aim was always to be on the upper border of the standard, at around 76 candles/nits. This ensured a a way better color reception, images in these theatres looked way better than at the lower border.
There is no difference in DCI these days. Auditoriums with a low light level look inferior to those that are on the upper level, as long as a modern High Contrast projector is used, and not 0.69" High Brightness.
Even those have improved significantly in black levels with recent models.
I have often screened images at 110 nits, the brightness set for the initial Todd AO standard being on the same level.
There was no oversaturation of colors, simply the images looked way better. With 12 bit encoding, there's enough dynamic range without a specially mastered output.
Another working mechanism on the human vision, the actual dynamic range is rather small, and far away from what we are doing. The eye accommodates to the brightness level, and then has a dynamic range below a 6 bit computer display of the legacy type.
WE must still keep in mind, a theatre is a dark environment, unlike a sunlit living room, which requires a 300+ candles/nit direct radiator. Also, our main sense is hearing, and image in 90's blockbusters has been only 15 to 20% of the perception value, when great dynamic mixes were norm.

LED direct radiation has a future, but there a many issues attached. I feel, they will find a way for sound with these. Remaining are 4 x around 9 Million micro radiators with control electronics. Even at 0.0X ct/ LED the price will never be 0. A power dissipation of 0.5 Watts in full brightness mode for LED and control, is still around 18 MW with full white short term, and an average that is significant, to be cooled away by A/C in the hall. Plus, a heavy load of plastics, eventually combustible plastics. I had a fire engineer that voted against heavy, active driven plastic in n assembly hall. In theory, I learnt from him, he has a problem with 100 lbs of PVC on the front wall (movie screen).
It comes down to price, that I doubt zo be low enough in in near future, fire safety issues, static structural issues, as well as maintenance issues. I expect small to midsize units to be first.

[Steve Guttag]

Projecting any standard content at higher than 48Nits is wrong and is oversaturating the colors. The movies were mastered at 48Nits. The light level was chosen to match film projection using a 16fL open-gate (no film so you have to allow for processed film exposed to the maximum light) so that when they did "butterfly" tests, the white points were as near to identical as possible.

You may prefer showing the movie at double luminance but you have no documentation as to it being better or not over-saturated. Have you had ANY film-maker/color-timer in your room think it looked better than when they set the color/image in their post house?

There are people (too many) that use 1.8 gain screens too and with those it is easier to hit 98NIts...in the middle. I'm sure some think it actually looks better too. It doesn't.