3D configurations (projector vs 3D apparatus versus server make/model)

[Steve Guttag]

As people start kicking the dust off of their 3D systems, we just stumbled upon a configuration conflict. I'm wondering if anyone has been keeping a list of known good configurations (3D files) for the various combinations of 3D apparatus (e.g. Real-D Z-screen) projector make/model, and server make/model.

For the longest time, "Line Interleave" has worked for most 3D system I've installed (it was not always that way...if one goes back to the early days). However, I recently found that line interleave does not work with say an IMS3000, Barco DP2K-15C and Real-D Z-screen. However "input reference -frame seq mode (polarity = true) " did work. Honestly, I don't keep up with what various modes are actually doing...I just select one that works and move on. Then again, it has been a LONG time since I saw a published list of what the best dark times are (and delay) for Real-D.

[Jim Cassedy]

I have a 3D projection question that I've never really thought about before-
My venue uses a pair of stacked SONY SRX-515p's for 3D. (and for 2D also)
Obviously, one projector is used for the left image, and one for the right- - but
exactly how is that handled by the playback system? Is each projector fed only
its' own image?; or is each proj fed both L & R and the filters do the rest?
I assume there's no double or triple flashing going on. One of these days, I'm going
to get around to actually measuring the light level on the screen, but my subjective
impression is that the dual projection system gives a brighter 3D image.
But exactly how does a dual projector system handle 3D playback?

Dual Stacked Sony's As Seen From The Auditorium
(Note the 3D Filters That Manually Slide Into Place)
DualSonyFront.jpg
The small device at the bottom of the window is a small camera
that's part of the SONY PACB (Projector Auto Calibration Box),
which is used to help during alignment & calibration.

[Marcel Birgelen]

In a polarized dual projector setup, you should do no flashing at all, to get the maximum light efficiency. Once the 3D show starts, one projector will project the left eye and the other the right eye with static polarizers applied in this case. For 3D setups, this is as good as it gets. No flashing isn't only dramatically increasing light efficiency, it also ensures absolutely no visible strobing effect.

If both projectors are being fed both images is a bit up to the intelligence of the Sony server. Most dual-stack systems consist of one server per projector. While they both have the entire DCP on storage, they usually only feed the relevant images to the projector, so the filtering happens on the server. If you want to play Gemini Man in 3D and 120 FPS, you need two modern Series 2+ projectors.

As for 3D modes, isn't this only relevant for alternative content input like 3D via HDMI or a Series 1 setup with SDI interface? AFAIK the default mode for DCI 3D should be sequential mode and only sequential mode?

[Marco Giustini]

With the 500 series the server was on the primary projector only and the picture was fed to the secondary projector via unencrypted signal - I think it was via dual display port?. For obvious reasons the video cables to the secondary projector were run in metal conduits and chunky flexible metal hoses. Besides a physical tamper through the metal, any removal of those ducting would disable both projectors.

As Marcel explained, in 3D mode each projector only plays its relevant eye. The role of the filter is to make sure that the output of the projector matches the relevant filter on your glasses.

With 6P laser, the only filters involved are the glasses: each projector will output slightly different RGB wavelengths which are then filtered exactly by your 3D glasses so that the Left eye picture only reaches the left eye and the Right eye picture only reaches the right eye. In other words, no filters needed in the booth as the light source is already "conditioned" and ready to use.

Other systems feature one server for each projector which then syncronise each other via a sync signal. That implies that both servers must have the same content on them and two separate KDMs have to be generated in order to play in dual projector mode (or 3D mode).

[Jim Cassedy]

(slightly edited quote)

With the 500 series the server was on the primary projector only and the
picture was fed to the secondary projector via unencrypted signal -For obvious reasons the video cables
to the secondary projector were run in metal conduits and chunky flexible metal hoses. Besides a physical
tamper through the metal, any removal of those ducting would disable both projectors..

You know your SONYs Marco! The dual projectors are connected together with cables inside a metal
hose-like conduit thing. The connections at each end are completely enclosed, in what I was told was
a "tamper proof" cover. When I started working this job, I was told (or more accurately: warned) not to
muck around with the cable or 'tamper harness' or it would disable both machines & I'd wind up in DCP
jail . . . or something like that.

"ACTUAL PHOTO!"
SonyDualCable1.jpg

[Marco Giustini]

Yep!

How did that configuration got approved by DCI escapes me but that's it

[Steve Guttag]

So, that's a "no" on any list of known working or best-practice configurations by equipment make/model and format?

[Marcel Birgelen]

Why no?

It has already one entry

1. Projector: Barco DP2K-15C
Server: Dolby IMS3000
3D System: Real-D Z-screen
Special notes: input reference -frame seq mode (polarity = true)
Contributed by: Steve G.

[Mark Gulbrandsen]

Is anyone still running their Dolby 3-D systems? I was told that Dolby stopped supporting the first type of system. Also, Sony's were always a kludge and the tamper proof connection only back up that theory even more.

[Jim Cassedy]

Is anyone still running their Dolby 3-D systems?

There's one at one of the private screening rooms I still sometimes work at.
I test it occasionally to confirm it's still working, but I can't remember the last time
they actually used it. I think I've run the 35mm machines there more often than the
3D in the past couple of years. Part of the reason for this, I think, is that this room
is mostly used for press & media screenings. We are usually sent both 2D & 3D
content & KDM's for a 3D title. Unless the studio insists on us running the 3D
version, the press people are given a choice of which one they'd rather watch.
99% of the time they ask to see the 2D version. One of the attendees once told
me that a lot of them use their laptops, i-pads, phones etc to make notes or to
check on assignments, and wearing polarized, or Dolby's wavelength division
3D glasses makes seeing the screens on their devices difficult to-impossible.

[Steve Guttag]

Most of our 3D systems remain Dolby 3D. Dolby is only not offering NEW systems. They still sell the glasses. So, so long as your colorwheel is working, you are still up and going and the consumables are available. Once the color wheel fails (either the wheel or the motors), then you'll need to move on to some other 3D (or, preferably, away from 3D).

[Marcel Birgelen]

Dolby 3D for xenon projectors has been discontinued and is currently only available for Barco and Christie 6P laser setups.

Dolby is still selling glasses for xenon based machines, at least around here.

Most Dolby 3D setups around here, unfortunately, have been phased out and have been replaced with RealD, including a nasty silver screen. So, in this case, 3D hurts your presentation, even if you're not using it.

[Steve Guttag]

We have one site (non-commerical cinema) where they've worn out their Dolby 3D system (xenon)...it does not reliably engage on the first try and it is an automated theatre. I've recommended that, if they want to retain 3D, to use an active glasses solution (e.g. XpanD) to avoid changing their screen, which is matte-white (and not large). This would also allow a projector change to laser, if it is in the cards.

[Mike Blakesley]

Our Dolby system still works, I fired it up a few days ago to test it out. I’m currently vacillating on whether or not to run 3D shows for Avatar 2.

My big worry is the glasses washer. I haven’t run that in at least 7 years or so. I’m a bit scared to try it.

[Mark Gulbrandsen]

Our Dolby system still works, I fired it up a few days ago to test it out. I’m currently vacillating on whether or not to run 3D shows for Avatar 2.

My big worry is the glasses washer. I haven’t run that in at least 7 years or so. I’m a bit scared to try it.

Yea, stuff has been sitting every where for so long that a lot of it is iffy. I am pretty sure there will also be a 2-D version sent out also. So if 3-D problems creep up, just get a KDM and switch to 2-D..