Is there a way to take multiple video signals using GEM, sample only portions of them then recombine them into a single frame.

For example I need to divide video into 4 separate sections across the screen, think of layers stacked on top of one another. the video will be sampled from multiple input streams such as camcorders. each camcorder covering a zone in the stack of video.

so simply put can you select a region in the gem output to display. something like a layer mask?

Check [pix_crop] I think this can be what you need.

Good luck.

to get multiple cameras in gem:
it works fine with unibrain fire-i firewire webcams. i did it with 4 daisychained cams under windows. but you will have to use the generic driver, not the shipped one.

i dont think gem can handle more than 1 usb cam.

thanks for the tips. I was expecting the need for firewire cameras for some reason and the fire-i boards look fantastic, and have some lens options which will really help out for this project, of course price is always an issue but there pricing isn't bad.

I'll give [pix_crop] a try sounds like exactly what I need to use.

Sonsofsol: how did the project handle the 4 input streams? Did you encounter any issues with delay or latency?

latency was about 750ms, image quality is realy nice 640x480 @30fps progressive scan.
and that is better than all usb cams i tried.
i daisychained 4 fire-i, plugged the last in the computer, power supply over firewire for 4 cams worked. in gem i mad 4 gemchains with 4 pix_film and select the 4 cams as different devices, wich i textured on 4 rectangles. see the patch.

http://www.pdpatchrepo.info/hurleur/record.pd

I am having some real issues with this. First I can't open the patch as it crashes right away. I am on a mac so I don't know if that is the difference.

In my existing patch I can not get pix_crop to work properly. I can get multiple input streams USB and Firewire to test for now until I can get 2 more firewire cameras. The patch seams to have all the info I need but I just can't seem to stack the video the way I need to or get the crop to work at all.

Bellow is my semi functional patch. Some things are hood up and others not as I am in the middle of testing it. But if you have any suggestions let me know.

http://www.pdpatchrepo.info/hurleur/video_project.pd

So I had some ideas should I be drawing everything into one [rectangle]
Is there a way of taking the stream of data and just displaying that in sections so part 1 is lets use an arbitrary value of 4000 pix then part 2 is 4000 then part 3 is 4000, but have them display as a a hole in one rectangle?

i dont get how you want it...
maybe you can explain in easier words what you want to do with your video signals.
you can

• map multiple videostream on rectangles (multiple gem chains)
• use [gemframebuffer] to map multiple gem chains (like described above) on one rectangle.

hope this helps

Well yes I need to take 3 video signals and stack a section of them to form one body or image.

so divide the image plane into 3rd's and put them one on top of the other. The idea is to have a section for head, torso, and legs, so they will be stacked vertically.

[gemframebuffer] i am assuming is the entire buffer for that video frame? So could you unpack it as raw YUV / RGB data and recombine the sections into one frame or is there an easier way to do this?

@dioioib said:

Well yes I need to take 3 video signals and stack a section of them to form one body or image.

for this id use 3 separate gemchains
everyone looking like:

[gemhead]
I
[translateXYZ] -- 0 -1 0 for 1st, 000 for 2nd, 0 1 0 for 3rd
I
[pix_video] -- device 1 - 3 or so
I
[pix_crop] (if needed)
I
[pix_texture]
I
[rectangle]

@sonsofsol said:

@dioioib said:

Well yes I need to take 3 video signals and stack a section of them to form one body or image.

for this id use 3 separate gemchains
everyone looking like:

[gemhead]
I
[translateXYZ] -- 0 -1 0 for 1st, 000 for 2nd, 0 1 0 for 3rd
I
[pix_video] -- device 1 - 3 or so
I
[pix_crop] (if needed)
I
[pix_texture]
I
[rectangle]

Sonsofsol regarding [pix_crop]I am having issues with setting dimensions and offsets as there is no information on the sizes. I find that I usually end up with a crop that does not fit to the dimensions required or is not in the proper offset. Am I correct in saying that the dimensions of the capture source are not the same as the rectangle and/or Gem window? If not how do I correct for this issue or does the placement of the [pix_crop] before the [pix_texture] correct the problem I was having?