Routing (visual) of content to other hosts for playout

Hi everyone!

I’m kind of stuck while making a decision here. We’re planning an installation in our university’s new building which uses multiple (7 or 8) beamers beaming onto balconies from different angels. I plan on using OF, that’s why I ask for help here.

Are there any common methods on how to deal with such a situation? I’d like to omit using one machine with 4 graphics cards and loooong video cables, since I don’t trust them so much (and I don’t know if we have machines capable of that many video cards).

My theoretically most preferred way would be having a central rendering host to generate the interactive visual content and route the content for the beamers via ethernet to playout-hosts controlling one or two beamers each. Is this somehow possible and/or common? I tried ofxStreamer but this is only capable of about 16fps (on my MacBook) with a delay of 500 or 600ms. I also found ofxGstRTP but couldn’t get it to compile yet. Is it possible to improve performance of such a setup or is this already the limit? (I don’t need frame-perfect sync and can live with, say, 100 to 200ms delay.)

Alternatively I could sync only the behavior of the stuff that’s happening on screen and render on each machine themselves. Or use the approach with the superlong video cables ;-). What experience did you guys make and are there well-tested and proven solutions?

Thanks for all advice! Best,
Benni.

Hey @bennigraf

First of all I am assuming beamers are projectors. A few questions

What kind of resolution will the total output be?
Whats the resolution for each output?
What is the max distance from the “render” machine to each projector?

I agree with not using one machine with 4 video cards. It sounds nice but you never get the performance you expect. Get a few Matrox TripleHead2Go’s. That way you could just use the one video card and let the triplehead do the splitting.

Running DVI or HDMI over long distance is impossible from my experience. I think they max out at about 20m. I have had good experience running HDMI or VGA over Cat6. With VGA over cat6 I have successfully run 150m. If you link this up with the triple heads it will work well.

The other option would be to use some projection mapping software specifically made for the job. This generally means you will need a computer for each projector(slave) and have one that will keep them all in sync(master). Think of the master as a remote control. It tells all the slaves when to play and keeps them in sync.

Hi there!

Yeah, we’re using beamers. We have a hand full of different ones and I haven’t tested on all of them, but I’m aiming for 1024x768. We also didn’t settle on the final positions yet, but theoretical cable lengths would be about 5m to 60m.

I didn’t know you could send hdmi via cat6, that’s a good tip ;-). I also didn’t know about those triple heads. That would definitely be an option (although it would raise the financial bar a bit :wink: ).

What projection mapping software do you refer to? Do they only do video playback syncing or is it possible to feed the slaves with dynamically generated content?

Thanks for your insights!

Benni.