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Combining two projectors for a cinema-sized screen?

peanutismint

peanutismint

peanutismint

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I'm trying to combine the outputs of two massive 7k projectors to create one massive cinema-sized screen in a lecture theatre where I work. Our display machine is running Windows 7 and is using an nVidia GeForce GTX 260 which has 2 x DVI outputs.

We've got the projectors lined up perfectly; weve used the soft edge blending function to eliminate any sign of where one screen ends and another begins. All that's holding us back now is the ability to fullscreen a video playing from an application like VLC so that it covers both displays.

If we fullscreen a video at present, it will only maximise to the size of one of the displays. Now I know that my computer at home has an ATI card which I know is capable of spanning a single desktop over two displays, as opposed to 'extending' the desktop onto a second display, so is this possible on an nVidia card? I read something about them taking the 'horizontal spanning' option out of their drivers? And someone else said that it's been taken out of Windows 7 too....??

We've also tried using that Ultramon program, and have even resorted to buying a Matrox 'TripleHead2Go' box which is supposed to split massive resolutions into separate displays, but we've yet to get either option to produce the result we require...

Any ideas what we could do? Is there any way to make a program like VLC allow a video to fullscreen across multiple displays??
 
lukext said:
Why, hes not trying to do eyefinity, its only two projectors? In any case, it maybe worth you trying an ATI card if possible.
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All eyefinity is is grouping multiple monitors in to one large "seamless" display (seamless isn't in reference to bezels, but how windows sees them).
 
Surely this is just the old Span function - used to be able to do this with the old 6800 generation of cards (just didn't as it only allowed 2 screens) - if I recall TBirdUK did this with his projectors - I'll drop him a line for you. Would be a shame if it does turn out to be a function that has been purposefully removed - might be worth looking around for some older drivers?
 
Yeah spanning - nVidia pulled the feature out their drivers (and made it quadro only :( ) a few years back - which sucked. In theory its been reintroduced with 3D Surround but I haven't tested it - so in theory a GTX260 or higher should be able to do fullscreen spanned video with the latest drivers.

If it is working then I'd go for this over eyefinity as you will have a lot less potential issues to deal with - for one ATI still doesn't handle certain hardware accelerated surfaces used for video acceleration 100% properly.
 
Thanks for the bits of info guys. Just as an update on this, we ended up finding a filter plugin built right in to VLC that splits your video into two separate windows (one on one screen, one on the other) which then both 'fullscreen' when you double-click, theoretically giving you half the image on one screen, half the image on another. There's even options to set an overlap in the middle to help the two images blend, and to change the brightness/saturation of the blend etc, very cool.

Anyway, it's not picture perfect; we're still fine-tuning but from nothing it's looking pretty darn good!! Just in time for putting our film exhibition license to good use! ;-)

If anyone has any more tips, please let me' know.
 
Cool, got any shots of it and the lecture theatre?

We have a large lecture theatre at uni... with two screens... and two projectors...

Doesn't get used much in the evenings...

*ponders*
 
Haha you should totally do it!!

Ours is actually a big hall in a students union which usually hosts the likes of Motorhead, Pendulum and Sum 41, but the university owns the building itself so they decided a couple of years ago to install bleacher seating and make it lecture-ready. So it's a tad larger than your average lecture theatre....

Here's a picture I tweeted on the day:

http://yfrog.com/n36dqj

As you can probably make out, the projectors have quite different colour temperatures, unfortunately, due to the age of the lamps (when one failed, instead of springing for 2 x new ones at the same time, they just replaced one, meaning the 2 x screens never look exactly the same.....) but I reckon we can alter the colour temps of each display independently in VLC.

For the actual film events we're gonna hire a proper 400 inch theatre screen so the image should look even better.

p.s. Some days I kinda almost love my job......... :)
 
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Look at buying the projector screen direct from Harkness Hall. I just bought a 6.1m wide (horizontal not diagonal) screen from them for £465 to run with two projectors. They are cheaper than you think ;)
 
Why can't you just manually resize the window over two screens?

I've pulled HD divx movies over 3 screens using only one 250gts and 8400 gt.
 
Rroff said:
Y
If it is working then I'd go for this over eyefinity as you will have a lot less potential issues to deal with - for one ATI still doesn't handle certain hardware accelerated surfaces used for video acceleration 100% properly.
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kylew said:
?
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You know full well he ain't going to back that up with anything substantial or anything that really matters because neither brand handles everything.
 
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