Forums > Jitter

very large movie, Open GL and low fps

August 18, 2009 | 3:13 am

Hi,

I’m working with a MacPro and I’ve installed a 4870 and a GT120. I used to work with 2048X768 movies and I’ve been able to have a fps around 60 using OpenGL. Now, I’m trying to play 3072X768 movies but my fps dropped down dramatically, around 8. I understand the problem is because I’m over the maximum pixels width my video card is able to work with but does anyone have a suggestion about the best way to workaround that problem? I figure I could use jit.scissors to split the video and then, sent that to 3 different jit.gl.videoplanes but I’m wondering if there’s a better solution. Also, I figure that if I’m using 3 different videoplanes, I’ll have to use 3 jit.gl.render and 3 jit.window, is it ok?


August 18, 2009 | 2:59 pm
Meriol Lehmann wrote on Mon, 17 August 2009 22:13
Hi,

I’m working with a MacPro and I’ve installed a 4870 and a GT120. I used to work with 2048X768 movies and I’ve been able to have a fps around 60 using OpenGL. Now, I’m trying to play 3072X768 movies but my fps dropped down dramatically, around 8. I understand the problem is because I’m over the maximum pixels width my video card is able to work with but does anyone have a suggestion about the best way to workaround that problem? I figure I could use jit.scissors to split the video and then, sent that to 3 different jit.gl.videoplanes but I’m wondering if there’s a better solution. Also, I figure that if I’m using 3 different videoplanes, I’ll have to use 3 jit.gl.render and 3 jit.window, is it ok?

Many ways to do this, but if you’re using one main display window, you only need one jit.gl.render and one jit.window. 3 different videoplanes, all in the same window/render context. If you don’t need all that resolution (it’s already a lot) I’d scale the movies down anyway.

Also I think that textures on videoplanes (and other GL objects) are restricted to powers-of-2 resolutions, but I could be wrong about that. Just use a subpatch or abstraction for each videoplane so you can send different position/scale/rotation/etc. commands to each. The scissors is only needed if you want to use different parts of the video on each, or you can work some texture offset magic.


August 18, 2009 | 4:29 pm

Thanks. Actually I forgot to tell I’m using three video projectors. I’m able to work with only one jit.gl.render and one jit.window and spread that to the three projectors but I’m wondering if that’s part of the problem of my low fps. Because I can get much higher fps on projects where I only used two projectors and 2048 pixels width.

So my question is more about the maximum size I cna work with OpenGL


August 18, 2009 | 4:38 pm

for best results, you should have a single window/render context pair for each graphics card you are sending frames to. (not port, a single card with two ports can utilize the "double-wide" window).

more info found here:
http://www.cycling74.com/forums/index.php?t=msg&rid=3061&&goto=171136#msg_171136


August 18, 2009 | 5:04 pm

Thanks for that info, that seems like I was looking for.


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