Film-Tech Forum ARCHIVE: How To: Dual projection 3D for Home Theatre

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Posted by Frank Angel (Member # 248) on 08-08-2010, 07:49 AM:

I want to use two digital projectors to do 3D off 3D BluRays in my home theatre. So far as I can tell, none of the 3D BluRay players on the market so far output separate left-eye/right-eye streams -- all are single HDMI "composit" outputs.

Question: Is there a way to separate those two signals so they can be fed to separate projectors, one for each eye, that can then be polarized with simple in-front-of-lens filters and thus allow a reasonable size audience using $1.50 plastic glasses instead of $80 a piece active glasses to see 3D movies? (As for the cheap polaroid glasses, I won't even have to buy them because we already have about 20 of them, mostly RealD and IMAX, which we've already collected from the 3D movies we've seen and took home the glasses which we paid a freakin $4 surcharge for).

One would think it would be fairly easy to make a L-eye/R-eye breakout black box for this kind of thing -- single HDMI composity into the box from the player, dual "stereo" HDMI outputs to the approproate eye projectors.

Posted by Steve Guttag (Member # 268) on 08-08-2010, 09:22 AM:

Yes they exist...they are pricey and non HDCP compliant. Doremi and Cine-Tal have them.

Posted by Claude S. Ayakawa (Member # 1401) on 08-08-2010, 04:29 PM:

Frank,

Dual projection in theatres is very impressive because of more light and the 3-D effects seem to be more deeper than single projection Real D, Dolby 3-D and Expend 3-D I have seen. I do not know how 3-D at home look when they are projected but I guess they would look the same like at a theatre but what I had seen on a Samsung and Sony Plasma screen at Best Buy is wonderful compared to single projection theatrical presentations.

-Claude

Posted by Mark J. Marshall (Member # 1409) on 08-08-2010, 07:53 PM:

Do those boxes output the eyes in sync or will they still alternate?

Posted by Frank Angel (Member # 248) on 08-09-2010, 12:34 AM:

Mark, I would assume that with the ability nowadays for fairly cheap frame store, there is no reason why both images couldn't be projected simultaniously in realtime.

Given that this would be a very easy and fairly inexpensive way to project 3D for more than just a few people and on a nice size screen, I would hope that eventually BluRay players would be offering both types of HDMI outputs -- one for single 3D displays like the standard 3DTV monitors as well as two for dual projection; built-in frame store to synchronize output for simultanious projection would be the iceing on the cake.

Posted by Mark J. Marshall (Member # 1409) on 08-09-2010, 10:47 PM:

According to the spec, they should be in sync already when they come out of the player. It's up to the display device to de-syncronize them if it needs to in order to display them (as the TVs do). At least that's my understanding. My question is on the boxes that Steve mentioned in particular - do the outputs end up in sync or out of sync?

Posted by Steve Guttag (Member # 268) on 08-10-2010, 05:35 AM:

They are in sync as there is nothing to take them out. What is done is to merely take a side-by-side image and issue two images...likewise for over/under encoding. The cost of these boxes will have most feeling like they are too expensive though...especially for home uses.

Steve