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Still any point in passive polarised projection?

Posted: Thu Sep 08, 2011 8:02 am
by Abydos
HI guys, I've been gone for ages. I bought a nice pj a few years ago in the hopes of eventually saving up for another one so I could make a polarised rig. I heard 3d vison and many others dont support these setups anymore though. I'm not even sure how good the 3d would compare to the new 3d projectors. I want full 1080p, should I just wait a few years for better 3d methods or the 3d pj's getting cheaper ?

Also, do game shops where you live have 3d tvs to display their demos yet? None by me yet. Also wouldn't tv shops benefit from this, from what I have heard games are far more suitable for 3d than tv could ever be, so what's up with this?

Thanks, Abydos.

Re: Still any point in passive polarised projection?

Posted: Thu Sep 08, 2011 3:40 pm
by Fredz
You can find several 1080p 3D projectors for under $1500 now if it's in your price range, like the Optoma HD33 for example.

Re: Still any point in passive polarised projection?

Posted: Thu Sep 08, 2011 7:49 pm
by cybereality
Yep, there are finally some 1080P 3D projectors out now. Probably a lot less hassle than building a DIY rig. Though I guess if you already have one projector maybe it won't cost as much as I think. If you do go the dual PJ route, you can play video with the Stereoscopic Player and games with IZ3D or DDD drivers. So there is some support.

Re: Still any point in passive polarised projection?

Posted: Thu Sep 08, 2011 8:50 pm
by Fredz
If you go the dual-projector route I'm not sure polarization is the best technique to use, Dolby 3D/Infitec sounds like a more sensible approach both from a cost and image quality point of view.

I'm also not sure the recent flow of 1080p 3D projectors are worth it now, it has to be confirmed that they are able to work in 1080p at 120Hz which is at least not the case for the Optoma HD33. It's 1080p only in 24Hz in 3D (for Blu-Ray 3D) and 2D but only 720p in 60Hz in 3D. So maybe the dual-projector route is the best choice if it's for gaming.

Re: Still any point in passive polarised projection?

Posted: Thu Sep 08, 2011 9:42 pm
by cybereality
Honestly the more sensible thing is to get a 720P 3D projector, which can be had for around $500 (I've heard good things about the Acer H5360). Currently HDMI 1.4a is limited to 720P@60Hz (for gaming) and only 1080P@24Hz for Blu-Ray. So even if you spend the big bucks on a 1080P 3D projector, it will have been wasted if you have to game at 720P.

Re: Still any point in passive polarised projection?

Posted: Fri Sep 09, 2011 12:32 pm
by Likay
I've been using dual projectors for maybe 10 years and no matter how much i would like to continue with it (nothing in stores is even close if you ask me...) i think it's a bad idea going this route right now. Nvidia has no interest in supporting older solutions and iz3d is maybe out of the game. There's still tridef for gaming but that's about it. For playing movies stereoscopic player (no blurays though) does a good job so no miss there.
I'd advise to go another route or wait until there's a more encouraging future for old school solutions.

Re: Still any point in passive polarised projection?

Posted: Sun Sep 11, 2011 3:53 am
by tritosine5G
I still think persistence is a bad thing, you don't need persistence , full frame length 16mS / 60hz hold projection is bright but not preferable, nor any hold display is preferable to me.

Re: Still any point in passive polarised projection?

Posted: Fri Sep 23, 2011 4:28 am
by BlackShark
tritosine5G wrote:I still think persistence is a bad thing, you don't need persistence , full frame length 16mS / 60hz hold projection is bright but not preferable, nor any hold display is preferable to me.
You know you can use DLP projectors on a dual-PJ setup... you can even use CRT projectors if you want.

Dual projectors is and remains the gold standard : it's the only technology which is full resolution, passive and simultaneous presentation in both eyes.
Polarisation is good but dolby is better, however the colour correction required for dolby remains a hassle. You need to use projectors with enough colour correction options otherwise you won't get the same colour between the eyes.

The biggest drawback for dual-projectors is support.
There is still no BluRay 3D player that supports it, you'll need to rip and reencode every BluRay 3D you want to watch. And getting drivers that work flawless is going to get much harder now that developers are starting to implement native rendering through GPU quad-buffers and iZ3D's silence.

The one thing that would definitely save dual-PJ would be converters with either "hdmi1.4 full bandwidth -> dual-PJ" or "Display Port 1.2 -> dual-PJ". which would unlock any 3D source to work with dual-projectors.

Re: Still any point in passive polarised projection?

Posted: Fri Sep 23, 2011 5:58 pm
by cybereality
I saw Dolby in the theater, and it is indeed the best. But seems a little difficult to DIY.

Re: Still any point in passive polarised projection?

Posted: Fri Sep 23, 2011 6:01 pm
by tritosine5G
-only CRT is standard, there is no dual projector standard, especially not with hold type projectors with loooooooong persistence

-you have a lot to learn about how human perception works, and what tradeoffs are necessary in a given scenario, I won't go into details anymore, maybe ask me in PM.

Re: Still any point in passive polarised projection?

Posted: Sat Sep 24, 2011 2:43 pm
by Likay
I get that when Blackshark says "the gold standard" he doesn't imply it IS a standard but could very well be for 3d. Nonethless dual projection is the best 3d-experience even after all these years. Softwaresupport have always been one of the strong sides for dual projection but lately it's more or less actively phased away...

Re: Still any point in passive polarised projection?

Posted: Tue Sep 27, 2011 2:49 am
by tritosine5G
Its not the best , since with 2d projectors, brightness comes with persistence, and that comes with excessive retinal blur (eye tracking blur, hold blur, etc,etc. ).
So it's a gold standard of self-delusion maybe ( like analog imax with its faux resolution, they had to keep it secret avatar is 'only' 1080p , remember the uproar when they changed to digital? lol ), nowhere best.

But I know , I know, retinal blur doesnt exist, nor it will ever exist, since it makes ultra bright 2d projector bundle less appealing, and we all know shutter glasses are least appealing. ;)

-Riiiiiiiiiiiight.... :lol:

-Evvvvvvvvvryone get two projectors and do the passive dance. :lol:

Re: Still any point in passive polarised projection?

Posted: Tue Sep 27, 2011 9:09 am
by Likay
Gotta love the final notes in you post. :P
Have you ever made direct comparisons yourself?

One room with two projectors, one room with pj and shutters. Where will 100 people go?
I could join you in the shutterglasses room though because i don't want someone to watch alone. ;)
Cheers!

Re: Still any point in passive polarised projection?

Posted: Fri Sep 30, 2011 1:23 am
by tritosine5G
Without getting personal, I think people in USA are perfectly fine with their DLP TV-s, despite some occasional "rumble" they see on their forums , like:
You've got sensitive eyes, most people don't identify this artefact when they see it.

I have not seen this movie but based on your description it's a normal defect caused by the active frame-sequential display technology. Since your eyes don't see the picture at the same time (frame sequential / shutter glasses) : it increases the stuttering sensation of 24Hz movies and distorts the perception of fast moving objects in your brain.
yeah, cause 24hz movie is perfectly okay , especially with dual projectors.
Guys, once you have dual projectors, you immidietly have to turn it into passive rig.
Once you are there, its so cool, you only have to check, how low can you go with the refresh.
Seriously, its that cool. Lower the refresh, it doesnt even matter! Best! Right on. :)
- dunno why AMD or nvidia isn't on board already, they should know better. Whole world is getting distressed because passive>active everyone knows ... That prestigeous company, LG , is barely keeping up, because of that active bias stuff in the mainstream :( , not right :roll:

Re: Still any point in passive polarised projection?

Posted: Fri Sep 30, 2011 4:16 am
by BlackShark
Tritosine you are distorting what I said.
DLP projectors and DLP rear-pojectors are fine for most people. It's amazing how they provide a great picture for a very low cost, but the picture isn't perfect and when someone spots it, I like to tell them the truth and explain how the TV is failing rather than just leaving them alone wondering if they have eye problems.
tritosine5G wrote:
I have not seen this movie but based on your description it's a normal defect caused by the active frame-sequential display technology. Since your eyes don't see the picture at the same time (frame sequential / shutter glasses) : it increases the stuttering sensation of 24Hz movies and distorts the perception of fast moving objects in your brain.
yeah, cause 24hz movie is perfectly okay , especially with dual projectors.
Guys, once you have dual projectors, you immidietly have to turn it into passive rig.
Once you are there, its so cool, you only have to check, how low can you go with the refresh.
Seriously, its that cool. Lower the refresh, it doesnt even matter! Best! Right on. :)
- dunno why AMD or nvidia isn't on board already, they should know better. Whole world is getting distressed because passive>active everyone knows ... That prestigeous company, LG , is barely keeping up, because of that active bias stuff in the mainstream :( , not right :roll:
When a movie was shot at 24Hz, there is nothing you can do about it. Playing it at it's native frame rate (or multi-flashing it at a multiple of the native frame-rate) is the best thing you can do if you don't have frame interpolation or if you don't like frame interpolation.

The point of Dual-projectors is not to lower the frame rate, on the contrary it is to keep the frame rate as high as the projectors allow, have as much brightness as possible, provide quality close to the 2D performance of the same projector in similar conditions and to provide a simultaneous picture in both eyes to prevent 3D motion artefacts.
24Hz motion looks better on dual-projectors than on active shutter systems, it is a fact that has been known for decades, even when multi-flashing the picture at 120Hz : 60Hz per eye is just not enough to compensate fully for motion artefacts introduced by frame sequential presentation.

AMD and Nvidia have been on board for years on their professional lines of graphics cards. The reason why they don't add it to their consumer products if because they believe there are too few consumers with Dual-projectors to justify breaking their closed and expensive professional market.

Re: Still any point in passive polarised projection?

Posted: Fri Sep 30, 2011 8:04 am
by yunti
BlackShark wrote:
The biggest drawback for dual-projectors is support.
There is still no BluRay 3D player that supports it, you'll need to rip and reencode every BluRay 3D you want to watch. And getting drivers that work flawless is going to get much harder now that developers are starting to implement native rendering through GPU quad-buffers and iZ3D's silence.

The one thing that would definitely save dual-PJ would be converters with either "hdmi1.4 full bandwidth -> dual-PJ" or "Display Port 1.2 -> dual-PJ". which would unlock any 3D source to work with dual-projectors.
Blackshark on your native rendering point - how does this make it more difficult to get to work for dual projectors, does it mean you can no longer sync refresh rates etc... ( I presume you are referring to games like Deus Ex etc...)

I never really understood this quad buffer stuff could you elaborate what that does?

And is there any development on a hardware convertor, anything coming out?
Thanks,

Re: Still any point in passive polarised projection?

Posted: Fri Sep 30, 2011 2:17 pm
by BlackShark
Native rendering means the game developers make the 3D themselves and they only implement the output they want/need. If they have never heard about dual-projectors or if they believe there are not enough people interested by dual-projectors, they won't implement it. Also since developers implement the 3D internally, they will be able to use rendering techniques that are not compatible with 3D drivers (Crysis 2, Avatar : the game, Trackmania, Deus-Ex). In other words : you can have a magnificent artefact-free picture but you can't display it on the dual-projectors, or use iZ3D/DDD drivers but the picture will be full of artefacts.

AMD and Nvidia provide Quad-buffers for developers, the quad-buffers act as universal outputs so that game developers can focus on making a great 3D picture, and then hand it over to the graphics card driver : the graphics card driver takes care of converting the picture into whatever format the display requires so that games developers don't have to worry about outputs and formats.
The problem is that neither AMD or Nvidia support Dual-projectors through this feature, they only support their proprietary displays (Nvidia), hdmi1.4 (both) and Display Port 3D (AMD). And none of them has much interest spending time and resources supporting dual-projectors in the future since it's a feature very few people would ever use.
I send AMD feature requests emails regularly, but I am pessimistic on the outcome.

As far as hardware converters go, the only current solution only works for hdmi1.4a (minimum specs = 1080p24 max), using an hdmi1.4 hardware clone/splitter and then two separate Optoma 3DXL converters. It's an expensive solution which does not support the full 1080p60 I want.
I've also hears rumours of some company studying the feasibility of a converter specifically targeting dual-projectors at AVSforums: user Pterodactyl claims to represent the company developing it http://www.avsforum.com/avs-vb/showthre ... st20493327" onclick="window.open(this.href);return false; but so far there is no official specs or target release window.

Re: Still any point in passive polarised projection?

Posted: Mon Oct 03, 2011 5:55 am
by yunti
BlackShark wrote: As far as hardware converters go, the only current solution only works for hdmi1.4a (minimum specs = 1080p24 max), using an hdmi1.4 hardware clone/splitter and then two separate Optoma 3DXL converters. It's an expensive solution which does not support the full 1080p60 I want.
I've also hears rumours of some company studying the feasibility of a converter specifically targeting dual-projectors at AVSforums: user Pterodactyl claims to represent the company developing it http://www.avsforum.com/avs-vb/showthre ... st20493327" onclick="window.open(this.href);return false; but so far there is no official specs or target release window.

Thanks for your reply Blackshark. That's a real shame to hear and the outlook doesn't look good for a dual projector setup which has high comptability with different games.

You would think it wouldn't be that hard to make a hardware convertor to convert an active stereo 3d stream from the pc to a dual projector setup by simply sending the left frame to the left projector and then the right frame to the right one. Or more likely it just isn't commercially viable for anyone to bother with.

Re: Still any point in passive polarised projection?

Posted: Sun Oct 23, 2011 3:03 pm
by Abydos
Thanks for the replies. Nice community. Looks like I'm going to have to hold out for now anyway, had a problem with unexpected payments.

Oh is it possible to change passwords here yet, I can't see where..

Re: Still any point in passive polarised projection?

Posted: Sun Oct 23, 2011 3:11 pm
by cybereality
Abydos wrote: Oh is it possible to change passwords here yet, I can't see where..
Yes, you can change your password in the "User Control Panel" on the top.

Re: Still any point in passive polarised projection?

Posted: Sat Mar 14, 2015 11:41 pm
by Shilar
Fredz wrote:You can find several 1080p 3D projectors for under $1500 now if it's in your price range, like the Optoma HD33 for example.
I looked it up, and that is active 3D. The person was asking on passive, aka polarized. To me, active doesn't work, and is a pain in my head to watch. I'm planning on buying that new passive 3D projector for $1500 here:

http://www.amazon.com/DAYJOY-LDCP500-Lo ... rds=dayjoy

To my knowledge, that is the only sub-$1500 all-in-one passive 3d projector compatible with RealD 3D glasses.

Re: Still any point in passive polarised projection?

Posted: Mon Mar 16, 2015 6:17 am
by Fredz
Thanks for the link, interesting. Too bad that it's way more expensive than active 3D projectors. I bought a BenQ W1070 some months ago for half that price and I'm very happy with it.