Forums > Jitter

multiple cameras

March 21, 2006 | 11:10 pm

hello,

in the jitter live input FAQ they claim "you can use as many unique devices as you can attach to your computer"

is this really true?

ive wrote a patch that SHOULD grab 5 images using jit.dx.grab from 5 seperate cameras and play them back.
(think Matrix the movie style)

i have managed to get three running at once,
but it was only after plugging all three cameras in seperatly,
and it only worked once,

now, only 1 camera will work….

ive been told that its impossibible,
but i still cling to the little hope that the jitter FAQ’s gave me.

has any one actually succeeded in this?

im using 5 different models of logitech cameras,
is it possible to attach firewire cameras instead ?

any help is greatly appreciated.

thanks,
anton


March 21, 2006 | 11:22 pm

This is also dependent on whether or not the drivers support it, and
any bus limitations (USB, FW). you might want to try using 3
different manufacturer’s cameras to avoid any problems the driver
might have with multi-cams.

-Joshua


March 22, 2006 | 3:09 pm

thanks,
ive read that multiple logitech camera’s = problems in the forums

before i go and drop $200 on webcameras though
i would like to know if anyone has actually succeeded in attaching more than two cameras for live input.

if so…..what was your strategy.

thanks again,
anton


March 22, 2006 | 4:25 pm

hi anton, my method of working with several cameras was to use frame
grabbers.
using frame grabbers have several advantages over webacms,
cheaper (for the same or better quality)
longer (&standard) cables
and, i was able to connect 3 cameras using three different noname brand
frame grabbers with only 20% cpu.
more expensive frame grabbers are able to process in yuv which are
supposedly better for jitter.
better ones also enable 2-16 inputs at pal frame rates.
some use firewire cameras (not dv) but i yet to have had the pleasure….
i would be glad to hear from anybody working with such
hardware< http://www.visiblelight.com/mall/productview.aspx?pid=764 >,
:::::::: <
http://www.cepoint.com/Video/transPAC6300vs.htm>


March 22, 2006 | 4:40 pm

Ive gotten 3 firewire sources working with the IIDC drivers on OS X,
without much of a problem.

2 iSights also work on the main firewire bus. Probably more, but we
didnt have another to test.

v a d e //

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March 22, 2006 | 5:01 pm

> Ive gotten 3 firewire sources working with the IIDC drivers on OS X,
> without much of a problem.

same here. 2 pyro webcams and 1 fire-i. not so much luck on an XP box,
though.
the ati wonder pro and alchemy miglia has 3 inputs: svideo, composite, and
"cable tv" (rf). You’ll probably need a converter to go from composite to
RF to use that last one, though.


March 23, 2006 | 3:17 pm

hey there

so this is what I got to work

4 fire-i cameras (using the supplied drivers NOT the QT ones)

not great frame rate and needs a hefty machine to run it (worked poorly on 1ghz powerbook but fine on a 1st gen iMac G5)

I was using it for a tracking system not for playback so a crappy frame rate worked ok for me – I can send you a patch if you like

part of my problem was also that I needed the cameras over the stage so distance was an issue – I found that the 30 meter firewire cable from granite digital to a powered hub worked well

the otherthing is that if you go with the fire-i cameras get the board cameras instead as you can then change the lenses in them – a serious plus.

let me know if you have any further questions

best
jamie


March 23, 2006 | 6:51 pm

> part of my problem was also that I needed the cameras over the stage so
> distance was an issue

I second this: the cabling can get quite expensive for many firewire
cameras. If you have to use a powerbook, then fw cameras are pretty much
your only option. if you can use a desktop with spare PCI/PCI-e slots,
then get a digitizer. I like the alchemy card, though I’ve had issues
switching between it and the firewire cameras in jitter – sometimes
switching from fw to Alchemy will introduce an ugly grey line or black out
the image – something about the image buffer gets corrupted, I guess. If
I toggle my camera on/off, that can sometimes fix it. Very fiddly :( I
haven’t tried using 2 alchemy cards and switching among all the inputs,
though.
On my XP box, the ATI Wonder card doesn’t have this issue. Seamless
switching between 2 Pyro fw webcams and the analog ins on the ATI card.
The nice thing about analog cards is that the analog cameras are much
better quality and generally better in low light than the fw cameras. And
the cables are cheeper ;)

P.


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