Videoin across multiscreen

can anyone hint me to this topic please?

  • i have a 5 screen dualview display setup.
  • i need external signal maped on a quad moving along my display
  • (for this, i have ordered the imagingsource video to firewire adaptor)
  • while it is on its way, i am testing videoin with a noname (i think) video2usb dongle
  • usb capture is working fine BUT on only one of the 5 displays, as if videotexture cannot be splitted on multiple adapters.

how can i translate videotexture across multiscreen ? tanks

hei ggml,

i am afraid you’re hitting a known problem here. the videotexture indeed only works on one device at a time (for now). so you’d need one videoin-videotexture connection for now, or you get all your displays in a big spanmode (where videotexture works across multiple outputs).

looking in Nvidia Control Panel (i have 8800s), i can only set spanmode for each card individualy, this means 3 cards = 3 spanmodes of each 2 screens = no deal? can you confirm this or is it possibel to run 3 cards in one spanmode ?

if one big spanmode is not possible, can i use 5 x videoin of the same source, with a texture switch or smth ?

or maybe another way to get realtime footage into v ?

right. you cannot span the desktop via several graphiccards.

it could work to use one videoIn->sharedmem->videotexture->quad
for one device. and then use sharedmemtexture->quad for the other devices. no word on performance though…please report your findings.


needed something similar some time ago and realized it with the following setup:

  • fast PC with nvidia 8800GTX
  • 2 Matrox TripleHeadToGo DigitalEdition connected to the two heads of the card
  • set both heads to 3072x768 (in case of XGA for each head)
  • put these two heads into span mode with 6144x768 (or to 3072x1536 using vertical span)
  • voilà now you have six outputs that can be used with one video in

If you are from the European-50Hz-PAL-world this solution has one problem:
The Matrox TripleHead is not working with vertical frequencies of 50Hz, so you will always have a stuttering video on your screens unless you use a camera or video source with 60Hz (NTSC).

I used a 60fps HighRes videofile as input and it worked amazingly good.


my ‘findings’ into this matter are:
videoin across shared memory works streched on 3 videocards pretty well. if anyone interested, i can report precise performance and system information. thanks joreg.

nevertheless, i got more problems with the capturing device:
as the imagingsource video2firewire converter that i was planning to use has arrived, i must say the cheapo video2usb camera works performancewise something like 10 times better …
debug mode says about the videoin: 12.0 for the usb capture device and 120 for the firewire device.
also, while the framecount in the videoout window is good, what i get in vvvv is much lower …
and theres the interlace problem with firewire, that i will have to look into, but only if i can do something about the capture consuming like that.

i use the imagingsource firewire converters too and i can’t support your findings regarding framerate and cpu usage. there must be something wrong with your driver or pc or firewire port ?

and yeah, the image is interlaced. use progressive scan cams from point grey, imagingsource, IDS imaging etc. lots of them out there.

oh, and regarding video accross multiple graphicscards, flash is able to display WDM cams and flash can be used as a texture across multiple cards. this solution is a bit like the shared mem idea.

have you tried deinterlacing with VideoTexture (EX9.Texture VMR9 YUVMixingMode) ?

firewire can be tricky. do you have multiple devices attached to your pcs-firewire ports? there seem to be some situations/firewire-port-cards/firewire-drivers where they share bandwidth and everything slows down.

i once managed to have 2 60fps firewire-cams (no converters though) running on one pc and remember that we had to try different firewire IO cards until this worked.