Output to a 3D TV via dual head DVI hardware + existing laptop scrn

[rjamesd05]

Can the various multiple monitor output technologies be used to drive a 3D screen?

There are solutions to connect more than 2 (two) - e.g. three (3) triple screen conventional 2D displays to a Mac or PC Desktop or Notebook. The displays each display different things - i.e. NOT mirrored duplicates. So this means that a desktop display can be extended over the multiple screens.

There are three kinds of solution:
USB to DVI: plugs into USB port of computer - display signal generate from this and output via DVI, e.g.: http://us.kensington.com/html/17534.html
For 17" Apple MacBookPro laptops/notebooks Full desktop PCI Express card installed in an enclosure box which then interfaces to the ExpressCard34 (only available on the 17" Pro out of the April2010 3 MacBookPro models): http://www.magma.com/expressbox1.asp
Custom hardware that attaches to the standard DVI output of the desktop or notebook: http://www.matrox.com/graphics/en/products/gxm/dh2go/

To me, the Matrox solution looks the best (third listed above) on grounds of cost and performance - using the DVI directly may provide the best sync performance between the display outputs - vital for left and right eye 3D.

So I was thinking, is there a TV, projector or monitor display that accepts two simultaneous DVI inputs: one for left and one for right eye, to provide the 3D? If so, then the matrox solution could be used to generate 3D images from a standard Mac, perhaps some software to send the correct images would be necessary too. Something like: http://www.cineform.com/neo3d/index.php but perhaps cheaper.

Other techniques that could be adapted for this hardware are here: http://www.dvinfo.net/forum/3d-stereoscopic-production-delivery/109177-stereoscopic-3d-editing.html

And some people have reported more than 3 multiple monitors attached to their Macs: http://www.cartoonbarry.com/2009/07/now_running_three_monitors_on.html
And here: http://daggle.com/macbook-pro-multimonitor-4-monitors-at-once-1577

Thoughts? Discussion?

Primarily looking for a solution that works with a MacBookPro 17", but other readers may also want thoughts on a PC based system.

[Cornucopia]

When you say "Drive a 3D screen", that's the crux of this whole matter, as there are MANY, MANY types of 3D screens.

If you're talking about a pair of projectors with polarizing filters in front of them projecting onto a polarized-retaining silver screen, then YES, those will work perfectly.
If you're talking about, for example, a Mitsubishi 3D-ready DLP TV screen that uses the "checkerboard" format, then NO, you would have to use either an intermediate device that converts from 2 separate video channels into a single video channel formatted in the desired format, or you would have to use software on your PC that outputs in that format directly, bypassing the whole "dual output" idea.
There are such converter devices already on the market, though they cost at least a couple hundred $ each (overpriced in my opinion). There are also software options for the 2nd, such as Stereoscopic Player and it's branded variant, nVidia's 3Dvision player.

I could give you more info, but I'd need more from you about the actual display (and glasses) option you'd be choosing...

Scott

[yoda313]

A major caveat is that you won't be able to do 1080p 3d unless you use hdmi 1.4. And I don't know the feasibility of doing 3d over anything other than hdmi. It might be possible but not at top quality for bluray.

GAMING is a different story. The above blurb is for bluray 3d.

[rjamesd05]

When you say "Drive a 3D screen", that's the crux of this whole matter, as there are MANY, MANY types of 3D screens.

Thank you for making me aware of that and for giving some examples of these below:

If you're talking about a pair of projectors with polarizing filters in front of them projecting onto a polarized-retaining silver screen, then YES, those will work perfectly.

Good to know! And encouraging!

If you're talking about, for example, a Mitsubishi 3D-ready DLP TV screen that uses the "checkerboard" format, then NO, you would have to use either an intermediate device that converts from 2 separate video channels into a single video channel formatted in the desired format,

There are such converter devices already on the market, though they cost at least a couple hundred $ each (overpriced in my opinion). There are also software options for the 2nd, such as Stereoscopic Player and it's branded variant, nVidia's 3Dvision player.

Couple hundred $ is an accessible cost. Obviously couple hundred more than I'd like to pay, but also encouraging.

...or you would have to use software on your PC that outputs in that format directly, bypassing the whole "dual output" idea.
There are also software options for the 2nd, such as Stereoscopic Player and it's branded variant, nVidia's 3Dvision player.

Another encouraging example.

I could give you more info, but I'd need more from you about the actual display (and glasses) option you'd be choosing...

Actually, I'm looking for that as part of my question - advice on what displays/output systems would take 2 DVI signals for left and right to display in 3D. Also general opinions on what I've said and anything else to consider. Forgive me for not making these aims clear. Despite that, I've got some really encouraging answers. The conclusions I'm drawing are that

• 3D displays come several types
• It is possible to work with them now, with existing hardware and software on both Laptops/notebooks and PCs, Apple Mac and Windows, with software and/or hardware add-ons
• Today's equipment is not rendered obsolete by the above fact
• The solutions are relatively affordable - i.e.: (after the initial cost of buying a platform and software) not necessarily additional multi-K add-on systems only affordable to business or rich people

Cornucopia thank you for your input.

A major caveat is that you won't be able to do 1080p 3d unless you use hdmi 1.4.

I'll take your word on that - for HDMI. But my question was about using 2 DVI outputs - each providing different display information - normally used to drive 2 external displays BUT instead I'm thinking about if there is a 3D display or projection system that could take these as left and right eye visual and combine them to be displayed in 3D.

And I don't know the feasibility of doing 3d over anything other than hdmi. It might be possible but not at top quality for bluray.

Well fortunately it does seem possible using DVI as Cornucopia replies above, at least with a projection system anyway. It's not beyond the wit of a monitor manufacturer to build a product that accepts 2 (two) DVI inputs as left and right (much like stereo audio) and combines them into a 3D image on the monitor's 3D-capable display.

Regarding 1080P 3D, fair enough about your comment about having to use HDMI 1.4. I think this statement means that if one is doing it via HDMI, then it must be v1.4, rather than saying HDMI 1.4 is the only way to do 3D and no other interface, e.g. DVI can do it.

However, it would seem that 3D at 1080P and beyond - i.e. 1920x1200 would be possible via dual/2 DVI outputs with affordable (~200$) hardware - i.e. via the Matrox DualHead2Go DP Edition ( http://www.matrox.com/graphics/en/products/gxm/dh2go/ ) will give 2 x up to 1920 x 1200 displays (with different display contents), in addition to the laptops own screen, for example, Mac or PC. So if we combine this capability with Cornucopia's polarized 2 projector system with each attached to a DVI output from the Matrox and with the appropriate software setup, then 3D at 1080p and beyond is possible via a non-HDMI solution using 2 x DVI.

GAMING is a different story. The above blurb is for bluray 3d.

Fair enough I'll take your word for it. I would like to learn more about 3D on blu-ray:

• Does it use the same blu-ray discs (e.g. 25Gb BD/BD-R/BD-RE and 50Gb BD-DL/BD-R DL/BD-RE DL)?
• Does it use different codecs?

yoda31 thank you for your input.

[edDV]

Dual DVI input 3D displays at consumer level don't exist. Development is centered on single HDMI 1.4 for large screens (Blu-Ray) and proprietary single connector solutions from NVidia http://www.nvidia.com/object/3d-vision-about.html.

Are you trying to do a custom 3D system? If so, the dual projector approach may be an option but you would need to write all the software to integrate electronic 3D glasses.

If you expect this to work with 3D Blu-Ray or NVidia 3d-vision games, you will need to buy from their supported hardware list.

A dual projector method.
http://wapedia.mobi/en/Polarized_glasses

[yoda313]

ll take your word on that - for HDMI. But my question was about using 2 DVI outputs - each providing different display information - normally used to drive 2 external displays BUT instead I'm thinking about if there is a 3D display or projection system that could take these as left and right eye visual and combine them to be displayed in 3D.

I'm not saying you can't do 3d over hdmi if you don't have 1.4 certified equipment. What I'm saying is I've been told that 1080p is not possible WITHOUT 1.4 equipment. You will get 1080i with pre1.4 equipment.

[Cornucopia]

yoda313,
the truth is "Consumer Electronic" "Single channel" "1080p" 3D is only possible with HDMI 1.4. But change that to PC-based, or dual-channel, or knock down the resolution requirement, and there are LOTS of options.

rjamesd05,
It all depends on:
1. What are you going to watch on it: Games? Scientific stuff? Videos?
2. Do you want/need a Consumer Electronic system or a PC-based system? And if PC, which platform(s)?
3. What is your method of viewing preference: Anaglyph (I hope not, Lowest Common Denom./fallback)? Linear Polarized? Circular Polarized? LC Shutter glasses? HMD? Autostereoscopic (no glasses)? some other way?
4. How portable do you need your system to be? And what environment(s) is it going to be used in?
5. Are you going to SHARE your system or your media with othere? And how many will be viewing simultaneously?
6. What's your budget? And what stuff do you already own and have to work with/around?
7. What are your requirements/expectations WRT resolution, framerate, color purity, etc?

Once I/we get more info, it's a LOT easier to tailor possible options.

Scott

[rjamesd05]

Thanks Scott/Cornucopia for your latest response, and to other posters here as well.

I guess another way to answer my question is: Can I record 3D films/movies and share these with the widest audience. I'm looking for a system that can output to formats that others can use, I want to share this on media (i.e. blu-ray) and over the internet. I'm not looking to setup a custom installation for an audience to come and watch.

yoda313,
the truth is "Consumer Electronic" "Single channel" "1080p" 3D is only possible with HDMI 1.4. But change that to PC-based, or dual-channel, or knock down the resolution requirement, and there are LOTS of options.

I would like to follow what the mainstream is doing regarding 3D standards that the public will buy as films or go see in the cinema.

rjamesd05,
It all depends on:

1. What are you going to watch on it: Games? Scientific stuff? Videos?

I want to make films, so videos.

2. Do you want/need a Consumer Electronic system or a PC-based system? And if PC, which platform(s)?

I want the material to be compatible with the mainstream consumer electronics systems (or mainstream standard, if there are any yet).

3. What is your method of viewing preference: Anaglyph (I hope not, Lowest Common Denom./fallback)? Linear Polarized? Circular Polarized? LC Shutter glasses? HMD? Autostereoscopic (no glasses)? some other way?

I'd like to be able to support as many as possible but really whatever the mainstream is used.

4. How portable do you need your system to be? And what environment(s) is it going to be used in?

Guess I've already indicated that this would need to be as portable as possible (i.e. the material is mainstream standard). If we mean portable as in having to transit equipment then that was not my intention to consider that - I would be making the material to whatever mainstream installed standard others use.

5. Are you going to SHARE your system or your media with othere? And how many will be viewing simultaneously?

Definitely the intention so would be look to support whatever standards are out there and including what is mainstream.

6. What's your budget? And what stuff do you already own and have to work with/around?

Not a large budget at all. Would be looking to base this around a 17" MacBookPro (Apr2010) with Final cut studio with a not more than say around a few 100$ to spare for any additional hardware. Assuming already have 3D camera.

7. What are your requirements/expectations WRT resolution, framerate, color purity, etc?

Whatever the mainstream are doing: 1080P 3D?

Once I/we get more info, it's a LOT easier to tailor possible options.

You ask very good questions about my aims/requirements that demonstrate a lot of knowledge on the subject.

I'm looking to set up a MacBookPro 17" Apr2010 editing system with software/hardware add-ons that would enable production of 3D movies (with appropriate camera). The 3D movies would be compatible with whatever mainstream standards out there to be able to reach the widest audience. My focus is on the specification of the production system itself and the output being compatible for others to view on their own purchased equipment. I'm not looking to setup a viewing facility.

To say it another way, if I wanted to be like a big film producer, producing a 3D film that the public can buy and watch at home or go see in a cinema, what standards/software/hardware would I use. I already know that Final Cut Studio is one of the professional industry standards. So could I buy a 3D TV and appropriate software to preview my edited material on, before releasing it for public consumption?

Can I use my external blu-ray burner to record 3D content onto, that will be compatible with home consumer 3D blu-ray based systems?

This solution I'm looking for is more medium term, i.e. I'm not looking to set it up straight away. But shorter term, almost immediately I'd be looking to work with Final Cut Studio on conventional 2D. I'm looking to see if the solution I have now is extendible, future proof, to some extent for 3D later on.

[Cornucopia]

Sorry, rjamesd05, for not getting back to you...
(it's crunch time @ work prepping for the next FY)

Ok, that's a little different than what I was thinking your were asking about earlier.

First, "Can I record 3D films/movies and share these with the widest audience?"

Yes.
What you should do is go through recording your dual videos (either with a stereoscopic camcorder like Panasonic's or Toshiba's or Fuji's, or with 2 standard camcorders shot either parallel-mounted or perpendicular with a beamsplitter, or with 1 camcorder shot either interlaced-field-alternating or anamorphically-split-screened, or a few other methods-like my own patent-applied version),
then cap them (usually separately) to uncompressed/losslessly-compressed files and use your editor of choice to create your final master file(s) - ALSO uncompressed/losslessly compressed. For HIGHEST quality, these should be either 2 full-resolution separate files/streams (I'm skipping dealing with audio for all this), or a single full-resolution dual-stream file - like Cineform, or a single file that is double-full-resolution (stacked over/under or side-by-side).




From this master, you would then make a copy/version for either:

1. DCI (Theatrical digital films), using the Digital Cinema Master/ Digital Cinema Package specification (MXF container with dual file assets of JPEG2000-compressed picture sequences). This currently can ONLY be done using DCI-certified tools and providers, so you'd have to send your stuff to those service bureaus.
2. Blu-Ray 3D, using the Blu-Ray 3D MVC specification (allows for MVC-AVC encoding, with either backward-compatible separate streams - MainView+DifferenceView, or with a single, dual-muxed, non-2D-compatible stream). This can so far only be done with Sony's BluPrint, Panasonic's ???, or NetBlender, AFAIK, although you might be able to piece things together with a combination of leaked Nokia+proof-of-concept tools and some reverse-engineered freeware and your own file structure reverse-engineering. Waiting another year for this will probably provide many more options...
3. (For PC-based systems only) Dual-muxed streams of AVI, Quicktime, MPG/MP4, WMV and/or possibly MKV to be played via Stereoscopic Player or NVidia's 3Dvision or TriDef players. These can be done by using your choice of compression (more standard = more popular) and then muxing them into a single file of 2 video streams. Doing this correctly with AVI currently requires the use of GraphEdit, etc. Doing this with QT can easily be done with QT Pro. For MPG, nearly ANY good MPEG muxer can do it. For WMV, you have to use Peter Wimmer's WMVmux (and possibly my) tool. For MP4, you ought to be able to use YAMB/MP4box. For MKV, you'll have to figure that one out yourself.
   These can even be formalized into a semi-STANDARD, like Peter Wimmer's WMV3D disc specification, or my Dual-mux DVD specification.
4. Use a more proprietary method and format. This could include Philips' now-defunct Wow3D format, Some of the older TriDef formats, SIS(sp?) format, etc. These are more limited in their audience and hampered by quality concerns.
5. Lowest Common Denominator -ANAGLYPH (although certain variations, like Optimized and Colorcode versions can be decent). Lots of apps can create this, just look around. Use only when there isn't a better alternative, but at least ANYBODY can view this, and with standard 2D equipment.

Then, it's just a matter of playback systems.

1. For #1 above, it would be RealD/DisneyDigital3D, XpanD, or Dolby/Infitec systems with the projector+screen+glasses combo already specified by the system. You would only specify which of those system(s) you wanted to use, and the service bureau would then craft the DCP for that system. In future, there should be a one-master-fits-all stereo3D DCP, but that hasn't happened yet.
2. For #2 above, you would check and see which Blu-Ray3D player is being used and what output options it's using (the spec is supposed to allow for many) and what display+glasses combo is being used (also many).
   I would guess that the most common would be outputting over/under, dualstream or checkerboard format to Samsung, Mitsubishi, Sony, Panasonic or Zalman 3D monitors/3DTVs. Since you're outputting to the player spec, you won't have to figure these out, each individual consumer will choose their own appropriate combo.
3. For #3 above, Stereoscopic player gives you (or more accurately, the consumer) a MULTITUDE of output options. Using the dual-muxed format as a master is a good combination of highest quality and 2d-backwards compatibility.
4. For #4, those proprietary systems each have their own required or recommended output options, so you'd have to follow them...
5. For #5, standard output systems and a pair(s) of high quality Anachrome or ColorCode glasses is your best option.

Given what you've got to work with:
MacBook Pro - You'd want to be able to dualboot into Windows as well. Use the 3Dtoolkit plugin with FCP, or better yet Cineform with FCP. Edit and render separately your left + right timelines (asset proxy/name swap is common).
Most all those encoding/authoring/muxing apps mentioned above are Windows.
Plus you would want to use certain tools in Windows to prep your L+R assets for what's known as "3D grading" to provide a calibrated+synchronized+eyepleasing 3D experience. You could even use freeware tools like StereoMovieMaker for this (although you could also use VERY EXPENSIVE tools like Scratch & Quantel Pablo). A VERY good compromise here is AfterEffects with the freeware 3D scripts plugin (do a google search or ask me later).


...??? $100 ???...That's barely enough for Anaglyph work. Maybe you could get a Fuji3D cam, demux using WIndows Graphedit, Edit with FCP (Left timeline), render L, then swap assets and render R, then back to Windows doing option #3 above with freeware tools. That's about your best bet right now to start off with. Got to learn to walk before you can run.

***Important RULE: 3D is a DELUXE medium, both to create and to view***
(Think about high end x 2.5 the cost)

BTW, to correctly EDIT 3D you **MUST** also set up a very good 3D viewing facility.

If you do #2 above, yes, you could burn a properly 3D encoded+muxed+authored BluRay structure to a BluRay disc (as Blu-Ray or possibly AVCHD).

FCP will almost assuredly be adding features for 3D, whether as plugins or as standard feature upgrades (either will cost you).


Hope that'll get you started down the right track. You'll have to do a bit more homework though, both on editing workflow, and on camera techniques+3D grading skills and concepts. A good start is "3D Movie Making" by Bernard Mendiburu (sp?), although even that is out of date (no 3D Blu-Ray info - it's just too NEW).

Good luck, and let me know if you have more Q's.

Scott

[rjamesd05]

Cornucopia/Scott - brilliant highly knowledgeable advice! Amazing. Thanks so much for your time. It looks really encouraging to be able to explore several solutions with existing hardware.

[JayLay]

Hi Scott,
I have been interested in setting up a 3D projection configuration using the two projectors with polarising filters method. I have been reading the other things you have mentioned. I have two matched projectors and polarising filters + a set of polarised glasses, the only issue I have is that I cant figure out a way of splitting the left and right eye images from my source, I have a Sony Playstation 3 which is 3d capable. I read that it may be possible using a HDMI to USB converter, I dont suppose you know any of these HDMI to USB devices that might do the job? The idea I had was to place one image from the HDMI source using a USB adapter onto one screen and the other onto the other display + then connecting both projectors to my dual output laptop (one on each display). Do you think this is possible?

Thanks a lot!
Jay

[Cornucopia]

JayLay, I've got a couple of notes/questions:

1. Are you using LP (linear polarizing) or CP (circular polarizing)? I prefer CP even though it has more possible crosstalk, mainly because of bypassing the tilt problem and because it's already compatible with RealD and their ubiquitous glasses. Make sure your projector filters and your glasses match!
2. With your PS3, are you expecting to be viewing Games or Video? The current firmware only supports Games (and only specially-tweaked ones at that), although an upcoming firmware is SUPPOSED to add support for BluRay3D with MVC encoding. This DOES NOT mean it'll support existing methods used on many PC materials (which I doubt it EVER will).
3. Were you planning on viewing JUST BluRay3D/MVC discs, or were you interested in other existing media (prepped mostly for the PC - SideBySide/OverUnder/Interlaced, etc)? This PS3/BR3D is likely the wave of the future, but it's not quite here yet as there isn't totally compatible firmware in most of the players out there, and there are LOTS of cross-conversion bumps that still need to be ironed out. As you've no doubt learned.
4. WITHOUT having a actual Dual-port HDMI PS3, you'll be needing a converter box of some sort. And that's where you come into problems. Inition, Cyviz, Barco and others make Active-to-Passive HDMI converter boxes, but they're $$$$! RealD makes converter boxes that are only $500, but all of theirs are meant for converting FROM a variety of things TO the 3D checkerboard format. Other makers are available for doing Active-to-Passive or Interlaced-to-Pasive, but they are older technology, using only Analog Composite NTSC/PAL video connectors, so the quality will be 2 or 3 levels lower than HDMI.
5. It could be possible to create your own BLACK BOX converter using a PC with HDMI inputs and outputs and using StereoscopicMultiplexer+SterescopicPlayer linked together as the software engine for converting in realtime. But this would be a bear to get just right, and it would be cheaper and easier to bypass the whole issue for the present and JUST get a MediaPC with a good nVidia Dual-head HDMI output card and Stereoscopic Player (or nVidia 3DVision player) and use it as your originating box. Then, you'd be able to connect DIRECTLY to your 2 projectors. (BTW, I am seriously considering building a similar converter box as mentioned above to sell to people, but it wouldn't be cheap!)

Food for thought. Talk to you later...

Scott

[JayLay]

Hi Scott,

Thanks for your reply!

I am using circular polarising. I was just planning on playing games in 3D rather than watching films (although if films are possible then i would give them a try).

I was interested in getting a 3D TV but remembered about the dual projection method working pretty well, however I do not know much about its limits. When I saw Sony announce the 3D update for the PS3 I thought I might as well give it a shot!

Would it not be possible to split both left and right eye images somehow from the single HDMI output on the PS3, and applying one eye to each projector, then aligning both images with trial and error? or is it not as simple as that? If this was possible I was planning on connecting both seperate images somehow to both projectors. The projectors I have do not have HDMI inputs, however they have VGA and are both capable of displaying 1080P, so I had a thought where I could place my computer in between to serve as a kind of bridge to convert the HDMI to VGA - then output both signals using dual display on VGA output. I have a Nvidia Geforce 7950GTX onboard my laptop with DVI, VGA and Component outputs. If the pc bridge method is not possible then I could borrow two HDMI projectors from university and give it a shot with those.

I think if this whole thing is possible then there is definitely money to be made with some sort of kit where the user can just add their own hardware. At the moment everyone seems to be raging for 3D!

Thanks again for your time!

Jay

[Cornucopia]

If the crosstalk on CP doesn't bother you, I think you'll find them very pleasant to work with, and if you spend a little extra $$ , you can get projection CP filters that are much more light efficient. Total luma output is very important.

I took some time these last few days to find out a little more about how Sony expects to process and output their PS3 version of 3D. It looks like the main variation, and one that is in line with the HDMI 1.3a and 1.4 specs, is the Over/Under method. If this is true, it MIGHT just be possible to just use an HDMI Y-splitter and send the same signal to both projectors, but then use the settings in the projector to CROP the top off the one and the bottom off the other and then align the remainder! Or, if your projectors can't crop, you could actually build a black matte, similar to the mattes that are used for cinemas. A little LOW TECH, but so what.

The bridge idea ought to work, but there's alot of testing that needs to be done, and you've got to make sure there isn't any inter-view delay, or tearing, or jitter, and you've got to have a system that can handle dual continuous HD throughput AND processing.

BTW, you didn't specify your projectors, are they DLP/CRT or LCD? If LCD, you'll want to look into the StereoBright method of gun-swapping (and it'll also make your choice of CP projection filters a little more straightforward, because the output is already pre-polarized, it just needs a 1/4wave retarder, which is nearly transparent.

Scott

EDIT: Oh yeah, you said your projectors don't have HDMI, so you'll need an HDMI to VGA(?) converter box or cable in there as well.

[datop123]

Hi Scott,

I have been searching and reading many forums about 3D solutions and by far you are the best knowledgeable and kind in taking your time, sharing your knowledge and giving a very, very detailed explanations. For that I thank you and wish all pros like you acted the same way.

My scenario:

I want to take 3D feed that is transmitted via satellite (Directv in USA, Sky 3D in UK, etc) and show it using projector on a big screen and use Polarized Glasses. All satellite boxes have HDMI 1.4 output. From what I read, all 3D ready projectors that are available now are only capable of showing 3D feed from computer and not from Blue Ray player or Satellite Box because they do not have HDMI 1.4 input. I even spoke to DepthQ Tech person about their Modulator and got same response that only feed from computer is possible as of now.

Can you please tell me what solution is possible? Is it possible to take feed from HDMI 1.4 and split it into 2 signals for Left and Right and send them directly to 3D projectors? If yes, can you give me specific device that can do the job? I do not mind spending few thousand on this solution.

Thanks,

David

[Cornucopia]

Thanks for the vote of confidence. Now all I need is for a Hollywood exec to recognize this as well and hire me! (HINT, HINT)

Not sure about which method Sat boxes are going to (you say already do?) output 3D, but if you're lucky and it's over/under or SBS, then like I mentioned above, you could take the LOW TECH road and matte out each projector's output downstream of an HDMI Y-split. (There currently aren't any "inexpensive" converter boxes...)

IOW, Sat out is e.g. Over/Under via 1.4 HDMI. HDMI splitter/repeater provides 1in-2out (or possibly more), both with Over/Under signal. One goes to L-Projector, other goes to R-projector. Projectors are vertically "stacked". In front of the lens of each is a matte. L-proj uses a matte with the rectangular cutout at the position of the "Over" image, R-proj uses a matte positioned for the "Under" (or vice-versa), and both have CP filters in line. Point the projectors so their remaining images overlap.
That and a Silver Non-depolarizing screen and RealD glasses should complete the system.

Not sure if that's really what you want, but it would work in the short term until more elegant solutions come to market.

Scott

[Cornucopia]

UPDATE that may interest you all:

Ok, I've been doing a little more research on this and here's my take on a possible, reasonable, high quality solution...

Say you're going PS3 HDMI out and want dual DVI or VGA in?
Get an "HD Fury 3" HDMI to VGA Adapter box (supports v1.3a and HDCP) $249-299. Set the box to talk the PS3 into outputting 720p(?).
Get a Christie "AP"Active-to-Passive box which takes a VGA input (with 3D options of Over/Under, PageFlip-FremeSequential, Field-Sequential or Interlaced) and outputs 2 channels of VGA and/or DVI. Don't know the price of the box, but I'm guessing $500-1k. I'm a little leary about the exact scan frequencies (and resolution requirements) being passed through or converted correctly, but other than that, it should all work as hoped. Yes, v1.3a doesn't EXPLICITLY support 3D, but there's no bandwidth difference between 1.3a and 1.4, so it's just possible that it'll accept it anyway.
Since the main options for 3D-over-HDMI include PageFlip, Over/Under and SbS, 2 out of 3 of those ought to be compatible with the "AP" box.

If this doesn't work, the idea of the HDMI splitter OUGHT to work - I found boxes lhat support HDCP for ~$50 (1-in, 2-out).

Happy Stereoscoping,

Scott

Edit: If the BD3D wants to use "Frame Packing", you're still screwed without some HDMI 1.4-capable converter. But I'm guessing that with RealD getting more into the Home Entertainment picture, there's bound to be more Passive (i.e. Polarized) options sometime soon.