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Use two HD33 and its build-in 3D demux function to build a Passive 3D system

post #1 of 16
1/29/13 at 5:18pm
Thread Starter 
As a long time follower to rdjam to his Ultimate 3D projection system and the 3DXL Owner's thread, I really respect his contribution in this area.
As an update to this issue, I provide my findings of using double HD33 and this build in 3D demux function to build a two projector 3D system.
HD33 is a product after 3DXL, I think it should be capable to handle a 3D to 2D demux job. After searching in its manual, I found this:




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post #2 of 16
1/29/13 at 5:20pm
Thread Starter 
I would put a system illustration chart here

Edited by Mrmy - 1/29/13 at 5:57pm
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post #3 of 16
1/29/13 at 5:26pm
I'm not caught up with the Ultimate 3D thread though I am curious about what is being demultiplexed? What are the benefits of doing 3D to 2D? Does it skip every other left and right frame to keep the video at 24fps?
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post #4 of 16
1/29/13 at 6:07pm
Thread Starter 
Quote:
Originally Posted by Seegs108 View Post

I'm not caught up with the Ultimate 3D thread though I am curious about what is being demultiplexed? What are the benefits of doing 3D to 2D? Does it skip every other left and right frame to keep the video at 24fps?

The two projector 3D system as in IMAX 3D needs separate the Right eye and Left eye 2D video streams from the original frame-packing 3D signals outputted from the BD player. And project each frame from two different projectors. This is where 3D to 2D demux needed.

Rdjam has creatively used two Optoma 3DXL boxes to do this job, has solved the HTPC only headache in doing two projectors polarized 3D projection. This was the only way to get a PS3 or a BD player or a 3D TV box connect to a polarized 3D projection system. Such a demuxer could cost a lot, but 3DXL is so cheap to make this happen in many 3D home theatres. That is just great.

Now this function has been intergraded into HD33, this makes the system much simpler ever. As we experimented before the 24fps 3D signal will turn into two 24fps 2D signals, each for one eye.

As the two projectors will synchronize to the same timing source the BD player, there should be no synchronization problem at all.
Edited by Mrmy - 1/29/13 at 6:27pm
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post #5 of 16
1/29/13 at 6:19pm
I see, so it's creating a separate 2D video for each projector and when overlayed it creates a 3D effect. For some reason I thought you were talking about something completely different. This is just a way to do passive 3D. Gotcha wink.gif
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post #6 of 16
1/29/13 at 6:33pm
Thread Starter 
In short it is passive. Compare to the active 3D HD33 carried with, you will see a much smooth 3D picture and have less eye strains, also a brighter picture than it was through a shutter glasses. The same feeling you can get from an IMAX 3D theater.
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post #7 of 16
1/29/13 at 6:36pm
With this system are you getting full 1080p resolution to each eye? I've read that is one of the drawbacks to passive 3D and one of the real benefits that frame sequential "Active" 3D systems offer. Joe Kane talks quite a bit about this in this video:

https://www.youtube.com/watch?v=4wr-tnrlLeM
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post #8 of 16
1/29/13 at 6:47pm
Thread Starter 
This passive system gives you full 1080P to each eye as it just separate the two 1080p frames from the frame-packing 3D signal. And throw any single pixel of 1080p picture for both eyes on to the screen and reflect to your eyes. Both eyes get the full HD picture simultaneously.(Passive 3D Flat TV is different, can’t get full 1080P HD for each eye)

Your video showed some points. But it really depends on personal feelings. I have tried active shutter glasses on 120 Hz SONY TV and 24’ PS3 3D displays, my feeling is dark and ghost images everywhere and my eyes have to try harder to get the 3D effect. When use passive 3D projection, There is bright spot in the middle of the screen, but not as much annoy as the ghost images the shutter glasses gives me. I will discuss how to deal with bright spot later when we get into the part of building a screen. Honestly the 3D effect from a activate system cannot beat the hundred years old technic that IMAX 3D are using.

Here is the passive system using 3DXL and HD20

Passive 3D projection photo:


Passive 3D projection photo taken through polarizing glasses:


The glasses used:

Edited by Mrmy - 1/29/13 at 9:05pm
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post #9 of 16
2/1/13 at 1:31pm
I was highly considering getting the HD33 but I just purchased a BenQ W1070 instead. I know the W1070 is a nicer box, but if I had known about this feature I might have given more consideration to the HD33. It seems easy enough to implement in the projector firmware itself and I'm surprised it's not standard. There are other uses for this besides the potential for dual passive, it would be useful if you started playing something in 3D and wanted to switch back to 2D for whatever reason. For the manufacturers the potential to sell their projectors in pairs is a far more financially compelling argument for adding this support. I don't know if this is enabled in any other projectors out there, I would be curious to see if any others models actually have this feature. I wouldn't be surprised to see it in other projectors, perhaps missing the ability to specify which eye to show. I can't imagine it would require anything more than a firmware update for existing 3D projectors to support this.

Maybe those of us interested in dual projection should contact our manufacturer of choice and let them know that they would easily sell us units in pairs by adding this feature (and none if the competition does). It would be nice if any of the forum members would check their existing projector to see if they can do the same thing with it. We can compile a list of projectors that work out of the box for dual projection (it's a short list if the HD33 is the only one that does it currently).
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post #10 of 16
2/1/13 at 9:31pm
Mrmy, can you fill in the details of your system.
1) Where did you get your filters?
2) What Screen is that. The new Vutec Silverstar 3D-P is curved so hotspotting should be minimal, but of course it costs as much as both the HD33's combined. Using mamimum throw on the HD33's will help a little, but they don't have much zoom range.
3) How did you align the projectors without lens shift? Of course you tilt them, but how much keystone correction did you have to do, or was it close enough to just leave?

Your brightness looks really good for a linear filter system. Is a single HD33 in 3D crazy bright on that screen?
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post #11 of 16
2/2/13 at 2:11pm
Thread Starter 
I use two 82mm camera linear polarizing filter (HOYA) brought from Amazon. Front side face projector Len, use maximum surface to polarize the output light. The filter is designed to minimize reflection and allow most possible light through then works better than other polarizer. It keeps cool in 2000 Lumen condition.
The screen costs me less than $200; spray silver paint onto the wall. It is a prototype; I did not consider reducing bright spot by then. Next time I will design a little curved shape frame and put canvas on then spray silver paint. The larger the throw distance, will give you the better effect of eliminating bright spot. It is better to make a small scaled model and test before start retrofit.
No keystone correction or lens shift should be used when align the projectors. It is for the reason of keeping the best possible projection quality. Some mount can allow you to do all the fine tuning jobs.
The brightness I get from two HD20 (Sorry I don’t have HD33 yet) under standard mode and actual projection size is 187 inch. I think the high gain of the screen and good quality polarizer are the reason.
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post #12 of 16
2/3/13 at 5:46am
Very interesting thread, thanks for sharing.

Now, how do you manage to achieve perfect pictures alignment from both projectors? I had two HD33 for short period of time when I was in process of replacement due to original projector having picture geometry issue. Replacement has better geometry but it was not perfect either. At the same time I also had HD23 and this one had flawless image geometry out of the box. This makes me wonder whether such passive brilliant in idea setup based on hd33 would produce perfectly aligned image.

Is your picture perfectly sharp corner to corner? Cheers.
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post #13 of 16
2/3/13 at 8:18pm
Thread Starter 
Quote:
Originally Posted by esdwa View Post

Very interesting thread, thanks for sharing.

Now, how do you manage to achieve perfect pictures alignment from both projectors? I had two HD33 for short period of time when I was in process of replacement due to original projector having picture geometry issue. Replacement has better geometry but it was not perfect either. At the same time I also had HD23 and this one had flawless image geometry out of the box. This makes me wonder whether such passive brilliant in idea setup based on hd33 would produce perfectly aligned image.

Is your picture perfectly sharp corner to corner? Cheers.


6m from projector to screen and the screen is flat; picture is perfectly sharp corner to corner. My projectors were new out of the box. Should not be a problem. But Refurbished ones must be cautious.

CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 90
Edited by Mrmy - 2/3/13 at 8:28pm
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post #14 of 16
2/3/13 at 8:25pm
Quote:
Originally Posted by Mrmy View Post

6m from projector to screen and the screen is flat; picture is perfectly sharp corner to corner. My projectors were new out of the box. Should not be a problem.

My both HD33 have been bramd new as well. Both sharp but with pinchuision distortion on top edge and barrel on bottom.
Have you installed and tried yours already?
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post #15 of 16
2/3/13 at 8:35pm
Thread Starter 
Quote:
Originally Posted by esdwa View Post

My both HD33 have been bramd new as well. Both sharp but with pinchuision distortion on top edge and barrel on bottom.
Have you installed and tried yours already?


Sorry I don't have HD33 right now, but my projectors are Reversely ceiling mounted how is yours?

The Len should be at the same height as the picture bottom edge or top edge if reverse mounted.




If this doesn’t solve the problem, then HD33 has a major defect in optical system which previous models don’t have. That will be a bad news. It shouldn’t happen on a $1300 value projector.
Edited by Mrmy - 2/3/13 at 9:08pm
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post #16 of 16
2/8/13 at 2:20pm
Quote:
Originally Posted by Mrmy View Post

If this doesn’t solve the problem, then HD33 has a major defect in optical system which previous models don’t have. That will be a bad news. It shouldn’t happen on a $1300 value projector.

I have been using several different PJ for last 12 years so I can know quite a lot about mounting these as well.
This flaw has been observed and reported by another HD33 user. Most people do not see the problem until they try to setup two projectors for passive 3D. Not worth the effort imho. Nevertheless good luck!
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