fps and multiple monitors

Feb 25, 2009 at 1:27am

fps and multiple monitors

Hello everyone,

I’m not entirely new to max/msp/jitter because I’ve been using it for a few months and have been doing live video manipulation performances with the patch I’ve created, but now I’m expanding with the hardware and the concepts I’m working with. Conceptually, I will be able to take the video I’m manipulating and export it to 3 projectors via a splitter hub, with each image echoing the previous. But from the 1st video to the second, I want to be able to slow down the fps to a crawl (maybe 5), and the 3rd even lower (to 1 or 2). If that can’t be achievable, or if it is easer, I’d like to have just a still be taken from video 1 and displayed on 2, as with from 2 to 3.

So basically my question is if anyone is able to give me a hand with playing video on multiple monitors and having the videos travel from screen to screen? ANY help would be greatly appreciated. Thanks!

#42510
Feb 25, 2009 at 2:27pm
stidem wrote on Tue, 24 February 2009 19:27
Hello everyone,

I’m not entirely new to max/msp/jitter because I’ve been using it for a few months and have been doing live video manipulation performances with the patch I’ve created, but now I’m expanding with the hardware and the concepts I’m working with. Conceptually, I will be able to take the video I’m manipulating and export it to 3 projectors via a splitter hub, with each image echoing the previous. But from the 1st video to the second, I want to be able to slow down the fps to a crawl (maybe 5), and the 3rd even lower (to 1 or 2). If that can’t be achievable, or if it is easer, I’d like to have just a still be taken from video 1 and displayed on 2, as with from 2 to 3.

So basically my question is if anyone is able to give me a hand with playing video on multiple monitors and having the videos travel from screen to screen? ANY help would be greatly appreciated. Thanks!

Unless your splitter can do some processing, which it probably can’t unless it’s pricey, the video will be the same on all 3 outs. However there are workarounds using multiple video cards or cards with dual outs. I suppose ideally you’d have a superbeefy desktop (quad-core would be great) with two dual-out video cards: one for your patch going to a monitor, then three more outs—one for each projection—complete with whatever processing you want before they go out (easy in Jitter, you’d just have a lower rate on your metros banging the jit.qt.movies). Not to mention any other FX you want, and probably four little preview windows in your patch. I’ve only ever seen 3 total video outs on any one machine, but I imagine 4 are possible…?

You could also use two computers with dual cards, which might actually be easier if you can just borrow one. So one would be the master and one the slave. You could have a laptop be the main one (patch and first projection as it only has one video out), and a desktop with a dual card to project the other two (no monitor needed as the controls are in the main patch). Use jit.net.send to send the video to the other computer, assuming the networking can be figured out, which may take some fiddling. Then you can also send processing commands via two jit.net.sends to the two jit.net.recv objects on the other computer (each has the same IP but a different port number), since you can send video (matrices) as well as any messages you want—like to slow down the metro, use “prepend metro” to identify the value you’re sending, then “route metro” at the other end to get the value to the right place(s). Probably this part is old news, just a little different when sending over a network.

Sounds interesting! Look into the jit.net.send/recv if you’re going to need to use two computers, they have worked well for me, though I haven’t tried super hi-res stuff much. You’ll probably drop frames (see Max window) but most likely this won’t be noticeable in the visuals.

#152100
Feb 25, 2009 at 8:59pm

For the splitter, you’re likely going to want the Matrox TripleHead2Go. Sounds like you currently have a device that is splitting your video output, which won’t give you what you need. If you have something like a MacBook Pro, one computer with the TripleHead2Go should do you. What you’re describing happening for the 2nd and 3rd outputs sounds like it wouldn’t put too much load on your system. The one difference is that the way the TripleHead2Go gives you access to the three outputs makes all three of them be one really wide monitor. So instead of three fullscreen scenes, you’re going to have one fullscreen scene, with three 1/3 screen sets of imagery going.

And like seejayjames said, once you have your first stream of video, you can just pipe it to the next output. The object you’ll want to start with at least is qlim. You might find you want to do something else once you’ve got that going, but that would get you started.

Ian

#152101
Feb 25, 2009 at 9:29pm

Thanks guys for your replies.

The Matrox ThripleHead2Go is exactly what I have and will use come finalization time. I have a MacBook Pro (but will run it off of either a Mac Mini or iMac) running max, so I’d be able to use that connected to three projectors. I think what I’ll have to do is just configure three jit.windows to fill the projector’s spaces.

I was just about to ask a question in the reply, and you already answered it for me suggesting that I look at the qlim object. My followup question is how would I add, and in what order, a metro to follow up the qlim? I’ve tried multiple configurations, but can’t seem to add it in. My patch is now looking like jit.pwindow – qlim – jit.pwindow, but I’d like the metro to affect the 2nd jit.pwindow.

#152102
Feb 26, 2009 at 4:48am

You can also have those three videos playing onto one window in three different places.

You just use the qlim inline with your video cables.

– Pasted Max Patch, click to expand. –
#152103
Mar 4, 2009 at 8:28pm

Wow, thank you so much for that reply. Although it did take me a bit to realize what to do with the text patcher (lol) it helped me realize how simple it was to simply just add to the qlim object. Thanks!

#152104
Jun 17, 2009 at 12:53am

Hello-
I am attempting to do something similar with triple-head-to-go and 3 projections of the same image only I am using OpenGL to render the footage. Is there an object that will split the OpenGL window in a similar fashion as you have done with qlim?

I tried rendering everything to 3 different jit.gl.videoplanes but this isn’t working correctly. The qlim example you give below makes a lot of sense and it seems like I should be able to something similar in the OpenGL context.

I would appreciate any advice, tips, help, etc.!!!
lmp

v8media wrote on Wed, 25 February 2009 23:48You can also have those three videos playing onto one window in three different places.

You just use the qlim inline with your video cables.

– Pasted Max Patch, click to expand. –
#152105
Jun 23, 2009 at 12:23am

this should work fine with 3 jit.gl.videoplanes

maybe just send your patch…

here the qlim with videoplanes

– Pasted Max Patch, click to expand. –
#152106
Jun 23, 2009 at 12:59am

Thank you MJ!
Your patch works like a charm for my situation except things have become more complicated since my original post. Now that I have the window split into 3 nearly exact images I need to render a jit.gl.sketch object on top of the video. I’ve created a simplified example patch. I posted a similar patch elsewhere on the forum, so I’m not sure if this is against forum etiquette to ask the same question in two places. Sorry if that is the case!
Thanks for your help!
Lisa Marie

– Pasted Max Patch, click to expand. –
#152107

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