A more efficient way for this, Multiple video and audio, Matrox ,windows 7

Jun 16, 2013 at 10:57am

A more efficient way for this, Multiple video and audio, Matrox ,windows 7

Hi there.
Working on an installation. 8 channel audio and 5 video streams.
Sfplay~ is playing an 8 channel audio file. Also it spits out the song position in milliseconds. We use this, to tell the jit.qt.movie objects, what frame to spit out. This is the sync part.
There are two jit.qt.movie objects. One is playing a film that is split into the four corners of the image. Four jit.windows are showing each corner. Separate jit.qt.movie and jit.window are for the fifth film. The five jit.windows are streaming to five video outlets via two Matrox M-series PCI cards.

This works fine, as long as there is not alot happening graphically. The image is staggering but the audio seems to behave.

Don’t know, if it is something in the patch that is not efficient or if it is an issue with the Matrox and Windows computer, installation, driver and all that.

We are troubleshooting on all fronts, you know.

Jun 16, 2013 at 11:00am

I’m trying to post the patch, but somehow, it won’t post it here.
I’m copying compressed and all that.
Any ideas why it doesn’t work?
There are sub patchers. Is that maybe a reason?

Jun 16, 2013 at 11:01am

Here’s the audio patch:


– Pasted Max Patch, click to expand. –


Jun 16, 2013 at 11:02am

Here’s the video patch:


– Pasted Max Patch, click to expand. –


Jun 16, 2013 at 11:32am

Some thoughts:

- Why are you splitting the video in 4 windows? Instead of tiling your videos 2×2 in the source video you can make it 4×1 and have 1 wide window that spans 4 display outputs. That’s likely to be more efficient.

- You might see a performance gain by porting your player patch to openGL. Stream your video into a jit.gl.videoplane. If you must have it, do your cutting also in jit.gl.* territory. You’ll take advantage of your graphics card’s hardware openGL acceleration. Lots of examples of this are floating around.

Jun 16, 2013 at 1:55pm


Just the kind of advice I’m looking for.

The video was like this, when I got it. I’ll see if it can be redone.. It is also alot tidier patch-wise, if it is 4×1, I think.

I’ll look into the .gl. stuff.


Jun 16, 2013 at 3:33pm

I’ve been sitting with this for a while now. I didn’t find a way in jit.gl to split the video.
I get it to work by using a jit.matrix. What gl object would be the obvious one to use for splitting this up?

Jun 16, 2013 at 4:05pm

It is of course with jit.gl.camera, right?

Jun 17, 2013 at 1:21am

No. You’d split the texture before putting anything in the 3d scene. Here’s 1 example: http://cycling74.com/forums/topic/opengl-scissors-and-glue/

But my point was you don’t need to cut yourself. Leave the 4×1 wide video as is. Run it into 1 videoplane. Make the window and videoplane size 4×1 ratio (eg. 4x800x600=3200×600) and position it at the top left corner of the leftmost triplehead display. The video window will now span 4 displays and – if everything is dimensioned correctly – the cuts between the videos should align with the display borders.

Jun 17, 2013 at 3:46am

I now have a different problem.
I’m writing the patch on my mac, but the performance is on windows.
The jit.window is only showing the topmost pixel when using jit.gl.videoplane.
Also in the jit.gl.videoplane help file.
A jit.pwindow shows the video as it is.
Any ideas?

I haven’t yet gotten the video file to be 4 displays wide. (it will actually be 5 displays) But I will have that in time for the performance.
For now, I’m using the test file.


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