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Author Topic: Output
chayden18
Newbie
Posts: 2
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Post Output
on: April 19, 2013, 03:37
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I know that in the tutorials you are using a Matrox graphics card, but can multiple projections be realized with other open GL graphics cards?

I am currently using 2 Nvidia NVS 300 (open GL 3.3 compatible) cards and trying to use 4 projectors on a Windows 7 pc. I am getting no output. Is there some routing I need to do? Or are my graphics cards insufficient?
Thanks for your help.

maybites
Administrator
Posts: 32
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Post Re: Output
on: April 19, 2013, 10:25
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I am a bit out of my waters in this question, I usually do a very empirical approach to these black boxes, tech.specs never tell the whole story, one only knows if one tries.

And I dont have much experience with multiple gfx-cards. the only time I used them was with OSX, and there the support is cumbersome, because a technology like SLI doesnt exist. SLI allows to share Textures between the cards (among other things), and MWServer relies heavily on this to get a nice performance (MacBook Pro Retina for example has two GFX cards inside and they must be somehow directly linked to each other).

And your cards definitly don't support SLI.

To make it short: Try other GFX cards.
To make it long: Try other GFX cards, because MWServer creates all the content on the GFX-card that is responsible for the desktop, but is unable to share the resulting texture with the other gfx-cards. (I am guessing here)

if you find a setup that works, please share it here. its always good to know which technical setups work.

good luck

PS. Do you have output on your output window when it is displayed on the desktop? what happens with it when you drag it to the other displays?

chayden18
Newbie
Posts: 2
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Post Re: Output
on: April 20, 2013, 02:42
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I do get an output in my output window, except when I toggle it to send it to the projectors/other desktops (which is how I am guessing is how you send the output).
And I can drag the output window to the other displays and view it there.

I will continue to tinker, but with due date quickly approaching I may have to cobble something together in Max. I will keep my eyes on this space though as I love the capabilities of the program (your finished projects look great!) I just need to get my Blender skills up to par and get this output thing sorted. Thanks, and if anyone can demonstrate an easy way to get an output even from a single projector it may shed some light on this for me.

maybites
Administrator
Posts: 32
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Post Re: Output
on: April 20, 2013, 09:45
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You are correct, the right way is to toggle the output window to the projectors on the left of your desktop. (There is another limitation though: MWServer's "rescan"-function supports only two additional gfx-outputs - if you have more you need to enter them by hand - but thats not you problem)

Your description of your experience points to my theory above. If you could do one last test for me: drag the output window to your projetor-desktops and scale it up while watching the framerate. I would expect a drastic drop in framerate up to the point where nothing goes any more. If thats the case, then you will probably run into the same problem with your own max-patch, because this shows that the video texture is passed on to the other gfx-cards via CPU and from a certain size on the pipeline gets clogged.

But I might be wrong, and if you find a max solution then I would be interested to have a look at it.

Craig
Newbie
Posts: 4
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Post Re: Output
on: September 2, 2013, 09:10
Quote

Output/frame rate problem.
I thought I would post my problem here as it seems to related.
I am running a Hackintosh with 2 x 'Nvidia GTX 660' cards... MWServer see's them both cards, although I have to manually giving screen dimensions. With this setup I can output to 5 projectors, no problem....

.....However the frame rate in MWServer is around 15fps, when running in both Windows 7, or Mac OSx 10.8.4
I can't use SLI tech, because OSX dosn't support it.
Dose anyone have any tips for increasing the Frame rate?
Note:
The Frame rate in MWS is 30fps or better, when running on similar machines with only one 'GTX 660' card

maybites
Administrator
Posts: 32
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Post Re: Output
on: September 2, 2013, 09:42
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Sorry, I don't think there is a solution for this. This due the way MWS is programmed, which is somehow related to the way the underlying MaxMSP Framework handles the problem.

Maybe you could get a better framerate with SLI on windows. But I dont have experience with.

On OSX its definitly not possible.

One problem (as far as I understand it) is due to the lack of sharing of textures between the gfx-cards. Since OSX doesnt support SLI there is no way to get any decent framerate over two GFX-cards.

The other problem is that MWServer layzily has only one outputwindow that it spans over the output-diplays. if the output-displays are on the same card (like the desktop) than that is no problem, but as soon as one of them is on a different card, the output-texture has to be shared by the two gfx-cards, and since the gfx-cards cant share textures directly, it has to be done through the PCI-bottleneck - hence the low framerate.

(this is what I think I understand of this problem, this understanding was gained out of dozens of hours of reassembling gfx cards and programming tests and staring at low framerates and frowning at stuttering video-playback)

So:

1. SLI on window might help, but I dont have experience with it. Would be interesting to hear from somebody that has got some.

2. Use ONE powerfull GFX card and split with Matrox TrippleHeads. The new MacBook Retina works sweet with two Tripplehaeds attached. MWS can run 6 projectors this way with a resolution of 1280 x 720 each with a solid 60 fps. It might drop a bit with a Syphon stream and another Videoapp running, but even with a syphon stream dimension of 5000 x 700 it stayed above 30 fps.

3. Wait and see what the new Apple MacPro will bring. Most likely the GFX-cards work together and share textures, so it might be a very powerfull videoserver. But probably not very affordable.

Craig
Newbie
Posts: 4
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Post Re: Output
on: September 20, 2013, 04:53
Quote

I tried a Windows SLI setup
2 x 'Nvidia GTX 660' cards with an SLI cable gave a performance boost.

I used a 8GB file at 3072x768 resolution. Meshwarp gave the following speeds:
Mac = 55fps
Windows with SLI = 80fps

maybites
Administrator
Posts: 32
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Post Re: Output
on: September 20, 2013, 16:04
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Marvelous, thank you for this valuable feedback.

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