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Topic: Dolby Cinema

Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001

posted 05-26-2015 02:26 PM

quote: Lyle Romer
Having dealt with fire marshals, it is very possible that everything was done/calibrated and he came in complaining about aisle lighting and whoever was there turned it up but didn't notice the effect on the screen.

They just need to tell the customers to stop setting fires in the theater. I mean, damn, no campfires in the aisles, right?
[Razz]

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Greg Staten
Film Handler

Posts: 6
From: Cypress, TX, USA
Registered: Apr 2015

posted 05-26-2015 03:53 PM

quote: Lyle Romer
You should really send an email to AMC (and Dolby if possible) regarding the light bleed. It might be something the fire marshal made them do but there may be a solution they can come up with.

Having dealt with fire marshals, it is very possible that everything was done/calibrated and he came in complaining about aisle lighting and whoever was there turned it up but didn't notice the effect on the screen.

Agree completely. I reached out to the folks at Dolby I've been working with on Dolby Vision (HDR mastering displays) and asked them to put me in contact with someone on the Dolby Cinema team so I could give them feedback. As it is only one of a handful of screens currently up and running surely something could be done - or at least corrected at AMC Willowbrook before that screen goes online.

IMO there's really no excuse for stray light in any premiere theater and certainly a Dolby Cinema installation should be viewed as that. Plus, if this is what AMC has planned for the roll out of the technology they may kill Dolby Cinema before it even gets going!

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 05-26-2015 04:32 PM

The avoidance of stray light is one of the basic design principles of this whole concept anyway. The black on black with black edges color scheme, the F117-compliant, faceted wall paneling.

The whole idea was that this Dolby Cinema logo came with the most strict compliance to "the standards" possible.

Still, I don't understand why proper movable masking could not be part of an auditorium design that apparently lands anywhere beyond the $2M mark...

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Jonathan Goeldner
Phenomenal Film Handler

Posts: 1360
From: Washington, District of Columbia
Registered: Jun 2008

posted 05-26-2015 09:55 PM

so apparently the El Capitan theater is a Dolby Cinema venue - and it's not part of the AMC chain - but it's Disney, so I guess it's the exception.

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Paul H. Rayton
Expert Film Handler

Posts: 210
From: Los Angeles, CA , USA
Registered: Aug 2003

posted 05-26-2015 09:58 PM

According to Howard Lukk, who's a high-ranking SMPTE member, there are 4 theaters in the US that were ready to show "Tomorrowland" in HDR. That's "High Dynamic Range", which is being branded as "Dolby Cinema" in these implementations. Actually there were to be 5 locations, but the AMC Burbank ran in to "issues" and didn't make it. However, the other 4: El Capitan in Hollywood, the aforementioned AMC Deerbrook 24 in Houston, the AMC Barrywoods 24 in Kansas City, MO, and one (name not provided) in Atlanta, GA. Some additional HDR locations are expected to be online for "Inside Out".

Specifics about HDR: It is timed/graded to be projected at 31FL (as compared to 14 to 16 for "normal" shows). It is intended to produce the High Dynamic Range of the name, thus allowing it to show textures in the blacks of the image.

At the El Capitan: it is definitely running there in the HDR mode, done with two customized Christie 4K projectors. They retain a 3rd "conventional" projector. The screen is (so I've been told) non-gain, and also is flat, not curved. They retain operating screen masking. I didn't think to ask if they'd changed the screen surface, or made any other changes to the ambient lighting inside the theater. They do have a silver screen for 3D, which "flys" up and is not in use now -- this is a 2D show. Not sure how or what would be done for 3D, or if 3D is even contemplated for HDR. (They use Real-D for 3D there, branded there as "Disney 3D", so what's the future for that is not known.)

The HDR is (according to reports) VERY impressive. A "film only" friend of mine saw it there and, so it seems, it's basically enough to push him out of the "film is the only way to see a picture projected" camp. There is ZERO publicity about the HDR, however. I assume it's because it's somewhat of what they like to call a "soft" roll-out -- don't brag about it too much until we make sure it's actually working OK and everyone is really happy with it.

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001

posted 05-27-2015 12:41 AM

quote: Paul H. Rayton
Specifics about HDR: It is timed/graded to be projected at 31FL (as compared to 14 to 16 for "normal" shows). It is intended to produce the High Dynamic Range of the name, thus allowing it to show textures in the blacks of the image.

I'd like to know the bit depth of the "HDR" movie files they're producing. Is it really HDR, implying the use of a lot more digital detail? Or is it the same bit depth movie files, but with the shadow detail and color levels cranked up a bunch?

If the latter is taking place the rave reviews will eventually shift to revealing lots of observed flaws. At limited bit depths you can crank up the shadow levels, color saturation and what not only so far before you introduce noise, posterization and banding on subtle gradients.

If anyone doesn't understand what I'm talking about they can find out by taking an image originally in 12-bit or 16-bit color depth, like that of a modern RAW image from a good digital camera. Save out a standard 8-bit JPEG version of it. Then work on the JPEG and RAW image at the same time. The RAW image in 16-bit depth puts up with a whole lot more push & pull with adjustments via levels, curves and other slider operations. The same operations applied to the 8-bit JPEG can yield terrible results. A simple levels operation can totally shred the normal mountain like peaks you see in the histogram.

I'm used to "HDR" being a digital photography thing for 32-bit per channel images that are combined from 3 or more different exposures and carefully tone-mapped to bring out the detail in every aspect from light to dark.

The "HDR" they're talking about in movies sounds a whole lot different. Unfortunately it's sounding a little fake to me. I guess I just don't know enough about what they're doing in the photography process and post production process to know for sure. Considering how movie production and exhibition companies have played very fast and loose regarding truth in advertising in recent years I feel justified to be more than a little suspicious.

quote: Paul H. Rayton
The HDR is (according to reports) VERY impressive. A "film only" friend of mine saw it there and, so it seems, it's basically enough to push him out of the "film is the only way to see a picture projected" camp.

I'm a film only fan if the movie is produced, post-produced and exhibited in a pure film-only mode. When the movie is shot on film and then bottle-necked through a 2K digital intermediate there's no longer any reason to see the movie on film at all.

Unfortunately there isn't much reason to pay first run prices to see a 2K movie in a commercial theater either. I feel like I'm seeing just as good a picture (if not better) watching it on Blu-ray at home -at least I know the image is going to be properly focused on the TV set. A movie like Grand Budapest Hotel, with its shifting aspect ratios (letter-boxed 'scope and pillar-boxed Academy ratio) seems tailored for watching on TV.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 05-27-2015 05:37 AM

Thus far, I've not met anyone that has seen HDR that didn't think it looked as good or better than anything they saw in film. There is something to having a 30+ fL white level. That is something one has only had in the home with CRTs and such and still retain black levels. I do not have the details of what they are doing to the picture to answer your bit-depth question though.

As for 3D...Dolby Cinemas use Dolby 3D with 6P laser systems so I'd suspect the El Cap will use Dolby 3D going forward. It will have 14fL 3D on a white screen. Dolby (Infitec) really benefits from the laser light since one can remove the filter since the primaries are already separated out via the lasers. It becomes the most efficient 3D system instead of the least.

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Greg Staten
Film Handler

Posts: 6
From: Cypress, TX, USA
Registered: Apr 2015

posted 05-27-2015 11:37 AM

quote: Bobby Henderson
The "HDR" they're talking about in movies sounds a whole lot different. Unfortunately it's sounding a little fake to me. I guess I just don't know enough about what they're doing in the photography process and post production process to know for sure. Considering how movie production and exhibition companies have played very fast and loose regarding truth in advertising in recent years I feel justified to be more than a little suspicious.

As I mentioned to you on another forum, Bobby, high dynamic range in digital cinema is a bit different from working with raw images in Photoshop/Lightroom or generating HDR images from bracketed exposures.

If you want to understand it, the best place to start is by digging through the documentation and explanations on the OpenEXR site and a good document to start with would be the Technical Introduction paper. It is written by color scientists at ILM and Weta Digital (as well as at Pixar, though Rod is included in the ILM group).

My understanding from my own discussions with the color scientists at ILM and Pixar is that it is very easy for them to generate HDR content as they are rendering it out anyway. This is likely why Inside Out is the second film released in the format -- and one I'm very much looking forward to seeing.

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001

posted 05-27-2015 02:06 PM

The question that remains unanswered to me is: just what kind of file is a Dolby Cinema theater playing?

If it's a standard DCI-compliant JPEG2000 encoded movie file with a 250 megabit per second bandwidth ceiling I'm going to be liable to call the "HDR" played in the movie theater fake. Standard d-cinema movie files do not have the bit depth to support HDR, even as it is described in the OpenEXR documents. What's worse is JPEG compression routinely uses chroma sub-sampling as part of the compression scheme. At best, they're seeing something in 4:2:2, if not 4:2:0.

I would hope that Dolby Cinema would be going around this with its HDR movies. And why not? IMAX gets to cook up their own specialized movie files, so why shouldn't Dolby be able to do the same thing? (especially if a Dolby Cinema theater carries a price tag of around $2 million).

There is a tremendous difference between basic, consumer level, 8-bit per channel color and 16-bit. There's only 256 steps from black to white in an 8-bit channel. There's 65536 steps in a 16-bit channel. Obviously the 16-bit channel is going to have a far better tonal range, but at the cost of consuming a lot more bandwidth and storage capacity.

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Carsten Kurz
Film God

Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009

posted 05-27-2015 05:37 PM

Bobby, there is something called DCI, or SMPTE ST428/429 documents.

https://www.smpte.org/sites/default/files/DigCinema_Wallchart_Final2.pdf
https://github.com/wolfgangw/digital_cinema_tools/wiki/Frequently-asked-questions

There is no 4:2:0 or 4:2:2 in DCI J2K.

IMAX is showing nothing else than DCI compliant DCPs following the same specifications, as is Dolby Cinema. 12Bit 4:4:4 XYZ.
Dolby Cinema currently does not yet have the final Dolby Vision contrast enhancement light engines available.

What they are doing different is they use special mastering/grading to deal with their specific brightness/contrast levels, tailored to their specific auditoriums.
If you have higher peak brightness levels and lower ambient light spill available in your circuit, you can use different gradings.

Which is basically the same process used for e.g. 4fL 3D - just towards the opposite direction. The result is always a DCI/SMPTE compliant DCP.

- Carsten

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Greg Staten
Film Handler

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From: Cypress, TX, USA
Registered: Apr 2015

posted 05-27-2015 07:51 PM

Carsten definitely helped set you straight, Bobby. I think you are confused about a lot of things. Since SMPTE charges a not insignificant amount for their excellent specs, you can also download and read the DCI spec here.

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001

posted 05-27-2015 10:37 PM

He set me straight on 12-bit versus 10-bit content. A bunch of the 3D stuff is 10-bit though. However, there is a pretty big difference between 12-bit and 16-bit content (or even 32-bit, which OpenEXR apparently does support). And then you have to consider all the extra things that can be done with OpenEXR. Not all of that can be compressed down into a 12-bit DCP with a 250Mb/s max bit rate. It certainly can't fit into current consumer video playback standards, and the consumer electronics space is the ultimate destination for Dolby Vision tech. That's why I wonder just what kind of video file a Dolby Cinema theater is playing when playing HDR content.

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Buck Wilson
Jedi Master Film Handler

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From: St. Joseph MO, USA
Registered: Sep 2010

posted 05-28-2015 01:51 AM

I saw Tomorrowland at one of the 4 theaters listed above... the AMC Barrywoods 24. The image was fantastic!

Whoever asked if they are keeping the "Prime" auditorium intact vs. remodeling it, at least at this location, they kept everything as it was, BUT all the speakers had been replaced.

I'm quite certain they were playing at reference, because it was LOUD. A bit too shrill to be as loud as it was, but everything was clear and I didn't walk out with a headache.

There was a "Dolby Cinema" snipe before the feature, but it didn't take advantage of the Atmos system like "Unfold" does. I was VERY excited to hear "Unfold" as loud as they had the fader, but alas, was majorly let down.

But again, the image looked fantastic.

Someone mentioned this:

quote: Paul H. Rayton
A "film only" friend of mine saw it there and, so it seems, it's basically enough to push him out of the "film is the only way to see a picture projected" camp.

I had the same thought in the middle of the feature myself.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 05-28-2015 04:32 AM

quote: Bobby Henderson
He set me straight on 12-bit versus 10-bit content. A bunch of the 3D stuff is 10-bit though. However, there is a pretty big difference between 12-bit and 16-bit content (or even 32-bit, which OpenEXR apparently does support). And then you have to consider all the extra things that can be done with OpenEXR. Not all of that can be compressed down into a 12-bit DCP with a 250Mb/s max bit rate. It certainly can't fit into current consumer video playback standards, and the consumer electronics space is the ultimate destination for Dolby Vision tech. That's why I wonder just what kind of video file a Dolby Cinema theater is playing when playing HDR content.

OpenEXR is an intermediate format designed to preserve as much of the fidelity of the source material as possible, not a delivery format. I don't think you need 32 bits per channel for a delivery format and 16 bits per channel should be sufficient in a linear color space to cover pretty much everything we can perceive, ranging from total darkness to retina burning brightness.

The Dolby Cinema setup is inherently compliant to the DCI specs for all DCI content, but... there is more.

The system, like many of the more recent Series 2 installs is capable of doing more than 250 Mbit/s. This particular system should be capable of doing HFR 3D in 4K. Compressing this down into 250 MBit/s will get very messy.

The Dolby Vision content apparently uses just 12 bits XYZ JPEG2000, but it uses a different color space, the so called PQ space as defined in ST 2084:2014. This is not a linear color space, but a logarithmic space. So, yes, they are stretching 12 bits per "axis" across a broader color gamut, but they're also exploiting the way human vision works to apply some extra "compression" to avoid things like posterization and banding issues. I've mentioned this before actually, as one of the possible solutions to achieve broader color gamuts without adding more "bits".

Obviously, the encoding side of things will need work. Your JPEG2K compression algorithm needs to be tailored to work with this new color space, to avoid artifacts building up. The rendering side of things obviously also needs some work.

On the production side of things... I'm not sure if any camera out there is fully capable of recording "HDR" in the full "PQ color space" in a single exposure. So, a lot of this HDR sauce will eventually be applied in post production. Then again, so many movies do get color graded or color "corrected" in post nowadays.

The Dolby Cinema systems in production right now, indeed do not feature the "Dolby Vision compliant" light engine. They are capable of displaying content mastered in this PQ space though. They should be upgraded with something like a "stepped" light engine solution in a later stage. This upgrade should finally bring the darkness back to cinema... I can't wait to see it.

As for the consumer side of things. Dolby apparently wants to leave the original color space intact for backward compatibility and wants to add their "Vision sauce" as a metadata stream.

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Carsten Kurz
Film God

Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009

posted 05-28-2015 06:05 AM

3D DCI is 12bit XYZ just as 2D is. 'Legacy' systems drop to 10Bit 4:2:2 YCbCr only for the transmission part over dual HD-SDI links.
But the projection systems we are talking about here all use IMBs, they use 12Bit XYZ and P3 through all modes, also for HFR.

- Carsten

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