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Need help with correctly projecting three 4x3 video to look like one 12x3 video

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eugene park
Need help with correctly projecting three 4x3 video to look like one 12x3 video
on Sep 14, 2009 at 10:43:37 pm

Hi,

I recently ran into some technical trouble with creating a video that would be played off a laptop which is hooked to three projectors (vertical/horizontal keystoning) by a expansion module (ie: matrox triple head 2 go graphics expansion module).

The projection would be unto a 9meter wide space on the wall for an exhibition. What matters most is that the projection would fill up close to that width and is matched up to seem like a very long move projection (3 projections side by side without seams)

First, I would like to ask what the best file type, compression, and resolution would be. I am working in after effects and formerly, i was using a pixel resolution of 3072x768 and was told that this would be fatal and would not play smoothly. I was advised to work in 2160x480 ntsc at 29.97 but was also told that 3072x768 isn't that bad at all.

I'm hoping that I could just play a video on the laptop, split by three projections to be aligned to look as one, however I am aware that this might prevent smooth play...

thanks for your time everyone, I'm a beginner trying not to get fired at work, I understand your frustrations with ppl like me. This was not a typical project I'd work on. Just an intern architect trying to assist with my boss's exhibition overseas.

Best,
Eugene


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Walter Soyka
Re: Need help with correctly projecting three 4x3 video to look like one 12x3 video
on Sep 15, 2009 at 2:29:43 am

I don't think that anyone is frustrated with you; rather, we're trying to help.

As I mentioned in the original thread on the After Effects forum, I don't think you're asking the right questions upfront. Before you worry about the After Effects setup, you need to sort out the physical setup, because this will determine what you need to do in AE.

It sounded to me like you were currently planning on using three 4:3 projectors side by side. That's not a good solution for a seamless widescreen display. Instead, you want to overlap the projectors slightly, 15-25% with an edge blend (with each image feathered on the sides in the overlap area), to make a seamless display. This will result in something narrower than a 12:3 display.

Once you have your projection finalized, then you can worry about how to design the content for it, but not before. I'd suggest that the correct resolution will be neither 2160x480 nor 3072x768. You will want to create your media at exactly the resolution of the blended projection display, which will be 768 pixels tall. We can't suggest a horizontal resolution yet, because the question of projection and the amount of overlap is still up in the air.

I ask again: are you alone on this, or do you already have someone helping you with the projection? Who's responsible for physically setting up the projectors? Are you working with an AV company or a production company? If there is someone, you need to talk to them about how they are planning on setting up projection. If not, you should try to get some help on this, because you really need the edge blend in projection to make this work well. Are there any other visual sources besides your video? If not, will the projectors have the edge-blending feature built-in, or will you need to manage the edge-blend upstream of the projection? How did you arrive at the solution you're currently considering?

There are a lot of considerations, but this is certainly not an impossible task. However, you might need some additional resources beyond what you are planning now to make this event a sucess.

Walter Soyka, Principal
Keen Live, Inc.
Presentation, Motion Graphics & Widescreen Design
RenderBreak: A Blog on Innovation in Production



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eugene park
Re: Need help with correctly projecting three 4x3 video to look like one 12x3 video
on Sep 15, 2009 at 3:57:56 am

I ask again: are you alone on this, or do you already have someone helping you with the projection? Who's responsible for physically setting up the projectors? Are you working with an AV company or a production company? If there is someone, you need to talk to them about how they are planning on setting up projection. If not, you should try to get some help on this, because you really need the edge blend in projection to make this work well. Are there any other visual sources besides your video? If not, will the projectors have the edge-blending feature built-in, or will you need to manage the edge-blend upstream of the projection? How did you arrive at the solution you're currently considering?

Thanks for your continued help walter.
I'm getting a better understanding of what I need now... slowly but surely

As for the questions you asked.. I do have someone helping me with projectors, kind of, because they are overseas and have not met them yet. It's a design exhibition in Korea, and I was told that a production team would assist me. They are aware of what I'm trying to do but I am not sure how thorough they understand because they haven't asked questions that you have, just accepted my requests (which is scaring me 3 weeks before installation). I was told that a specialist would be on site, but not sure what that really means. I did draw a diagram of how I wanted the projection set up.. all three would be on a tray hanging from the ceiling so they will all share a central location as well as the laptop and expansion module. So one would be projecting straight foward and the two on each side would be projecting at angles. The maximum width of the space is 9.5 meters and height is 4meters.

the type of projectors i requested were ones that have both vertical/horizontal keystoning which i am aware arent features of all projectors. I was only aware of this, because it was the only thing an a/v specialist at a local institution advised.

this may be a bit of an ignorant statement but if the width is off by inches, I don't think it would hurt the presentation too much. I am projecting a lot of full bleed images of our research and very large short text (sentence or a quote) of projects and the video is almost for an added effect to the space. there will be no other videos projected, the only other work in the space will be our models on bases.

I think I will be able to request projectors with edge blending and the way i arrived at the solution im considering was by asking ppl around me. should have came here earlier though.

So up to this point in my mind i thought that if i have the file in the right format (dvd/file) and as long as it is compatible with the equipment provided then it would be fine. I am waiting for info regarding the specs on the machines they plan to use.

thanks for your time.


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Walter Soyka
Re: Need help with correctly projecting three 4x3 video to look like one 12x3 video
on Sep 15, 2009 at 10:29:26 am

[eugene park] "I did draw a diagram of how I wanted the projection set up.. all three would be on a tray hanging from the ceiling so they will all share a central location as well as the laptop and expansion module. So one would be projecting straight foward and the two on each side would be projecting at angles."

I am really glad you mentioned this, so I could try to talk you out of it. This will give you fits trying to align, it will degrade the image from the excessive keystone distortion (if you can even keystone it enough), it will suffer from focus problems on the outer edges, and it will be non-uniformly bright. Projection should always been on-axis. Playback hardware shouldn't be co-located with projection in the ceiling in case it fails and needs to be accessed.

Go back to your AV company and talk about the result you need, rather than how you think you should achieve it.

If they cannot provide you with a competent project manager, then I think you need to hire a technical director to help you through these issues. There are so many other considerations: what screen material to use; how bright projection needs to be and where it's possible to hang projection in the space, both of which will affect how many projectors you need; what your options for playback are, etc. We haven't even touched on audio or the lighting in the room... The scope of the project and its needs might be bigger than you realized at first, and you would benefit from bringing someone onto your team who go over your project, its requirements, and its technical design from top to bottom.


Walter Soyka, Principal
Keen Live, Inc.
Presentation, Motion Graphics & Widescreen Design
RenderBreak: A Blog on Innovation in Production



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maurice jansen
Re: Need help with correctly projecting three 4x3 video to look like one 12x3 video
on Sep 15, 2009 at 3:38:21 pm

wow

your a bit on thin ice here. indeed try to arrange a senior projectionist. for setup. be aware that a Edgeblending setup demands good technical knowhow. as you stated you want to use keystoning. this is not a wise things to do specialy when the projector's have to make the Blend which can not be done. if the Blend is in the content or made by a widescreen processor you could get away whith it if your content is forgiving. but it certainly isn't a good situation. linearity change when you project with a keystone. this is very hard to align. not even talking about brightness differences between the top en the bottom of a keystoned projector. as mentioned by the rest for the content making your setup is the drivingfactor not the other way around. keep mission critical stuff on the ground!!! try to contact and findout what projectors are used and whatkind of playback.

kind regards
Maurice


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Brian Lynn
Re: Need help with correctly projecting three 4x3 video to look like one 12x3 video
on Sep 17, 2009 at 4:03:28 pm

3072x768 projection would be best accomplised using two 1920x1080 native projectors such as Christie Roadster HD12Ks. The native 1920 resolution side by side with a blend of 768 pixels (a region in the middle where both projectors overlap) would give you a total pixel space of 3072 wide. You would be over shooting your screen top and bottom (or one or the other) and you can mask that with projector "blanking" or a physical flag system.

The other responses to your post are correct... your biggest concern is your playback method.

I have had good luck with DDR systems like the Grass Valley Turbo or a DoReMi V1UHD. I personally use Macintosh computers running PlaybackPro which is easily synced.

I use ONE computer PER projector... I have not had very much luck playing super widescreen video files over a Matrox TripleHeadToGo style setup... You will need a beefy machine to handle the large format video and split it up properly.

As stated above there are lots of technical aspects of what you are trying to do that would be best addressed by someone who has done this before and can help you...

If you HAVE to use "a" laptop to play this back, and you HAVE to use standard def projectors (4:3 instead of the above mentioned 16:9 native) I would use three laptops, one to feed each projector.

Pixel space is very important. At 3072 pixels wide and 4:3 projectors you should really be using 4 projectors with blended edges to get your full pixel space...

Hope this all makes sense!



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