Forums > Jitter

5 cameras with jit.qt.grab

April 19, 2007 | 1:23 am

i need to get video from 5 cameras, i don’t really care what this does to the frame rate i just need to get it to work. i tryed dv cameras which i couldn’t get to function. i can get the computer to recognize 1 firewire camera and the isight but not even a usb dv camera. i read a lot about the unibrain cameras, but does this work? i would like to know that it works and generally how before i buy them. thanks a lot


April 19, 2007 | 1:44 am

hey josh

indeed, I have used 4 unibrain cameras simultaneously – couple of suggestions for 4 cameras
use at least a 1.5 ghz powerbook – my 1ghz crashed pretty regularly and the frame rate was seriously a crawl

the unibrain cameras ship with a driver that cycling 74 does not recommend using –

however – I found that one major issue was being able to tell what camera I was addressing when – particularly because if you make a mistake and try to send the same camera into 2 jit.qt.grab objects max crashes –

anyway – using the supplied camera you can give each camera a unique name that stays linked to the serial number of the camera -and thus you can easily know which camera you are addressing.

perhaps there is a different way to do this but I found this to work.

it was definitely a long road of trial and error to get my system running – though it’s been 3 years and might be considerably easier with a better machine.

good luck
jamie

ps – the unibrain tech support are FANTASTIC – another good reason to go with them…

—– Original Message —-
From: josh Powell
Sent: Wednesday, April 18, 2007 9:23:36 PM
Subject: [jitter] 5 cameras with jit.qt.grab

i need to get video from 5 cameras, i don’t really care what this does to the frame rate i just need to get it to work. i tryed dv cameras which i couldn’t get to function. i can get the computer to recognize 1 firewire camera and the isight but not even a usb dv camera. i read a lot about the unibrain cameras, but does this work? i would like to know that it works and generally how before i buy them. thanks a lot


April 19, 2007 | 3:48 am

For a dance piece we just completed I had two unibrain cameras and an ImagingSource DFG1394-1e (using only one of the 3 analog inputs) all chained on one firewire bus to my 1.67 MHz PowerBook. This was all new equipment for me, but it worked beautifully. I only intended to use the unibrain cameras for motion capture data, but we ended up mixing the RT images from them with that from the big Sony that was connected to the DFG1394. The frame rates were very good, the image quality worked for our purposes even with low stage lighting, and everything worked as advertised. When compositing or xfading the feeds, there were small but apparent time differences between the images, which actually was a pretty cool effect in the context of our piece.

We used 3 individual jit.qt.grab objects so we could combine the outputs as needed. I also tested the setup using one instance of jit.qt.grab, and switching between the inputs–this performed well too. No problems.

I highly recommend the unibrain stuff, even the Fire-I, which is what I used in order to stay in budget. (You may want to opt for the board version if you need a specific lens other than the one that comes on the Fire-I.) Also, you can get good 10 meter cables from them!

The DFG box is really cool too. If you already have the DV cams, just get one of these nifty little boxes and grab analog output from three of your cameras. OSX Jitter and the DFG with the ASC driver play together really well.

I’ve heard these products recommended on this list and elsewhere many times for use with Jitter. My own recent experience with them proved to be brain-dead simple to setup with no hassles and superb performance.

Tim


April 19, 2007 | 10:06 am

Never done it with 5 but I’ve ran 2 unibrains a dv and isight at the
same time and it was fine.

jk
On 19 Apr 2007, at 02:23, josh Powell wrote:

>
> i need to get video from 5 cameras, i don’t really care what this
> does to the frame rate i just need to get it to work. i tryed dv
> cameras which i couldn’t get to function. i can get the computer to
> recognize 1 firewire camera and the isight but not even a usb dv
> camera. i read a lot about the unibrain cameras, but does this
> work? i would like to know that it works and generally how before i
> buy them. thanks a lot

Jack Keenan
3sixty-tv coordinator
Peacock Visual Arts
21 Castle Street
Aberdeen
AB11 5BQ

01224 639539

http://www.threesixtytv.com
http://www.peacockvisualarts.com


April 19, 2007 | 1:49 pm

One cheap approach we use often is to use a "color quad" security
camera box, followed by an analog to digital converter. It’ll take
four video camera inputs and pack them at quarter rez into one video
output that you can then digitize/import into jitter (thanks
tinapple). If 320×240 streams are "good enough" this is a cheap
solution for getting four cameras into one firewire port – then you
just need one more :) -matt

On Apr 19, 2007, at 6:06 AM, jack keenan wrote:

> Never done it with 5 but I’ve ran 2 unibrains a dv and isight at
> the same time and it was fine.
>
> jk
> On 19 Apr 2007, at 02:23, josh Powell wrote:
>
>> i need to get video from 5 cameras, i don’t really care what this
>> does to the frame rate i just need to get it to work. i tryed dv
>> cameras which i couldn’t get to function. i can get the computer
>> to recognize 1 firewire camera and the isight but not even a usb
>> dv camera. i read a lot about the unibrain cameras, but does this
>> work? i would like to know that it works and generally how before
>> i buy them. thanks a lot


Matthew Lewis
Advanced Computing Center for the Arts and Design (ACCAD)
The Ohio State University

http://accad.osu.edu/~mlewis


April 19, 2007 | 3:02 pm

i can confirm the quad splitter method, just get a good one as some can give
a delay or mess the colors.
i also work a lot with unibrain. aside from about 1 of 10 being bad apples
(althu they will replace bad ones) i get good performance with these.
if your in desktop land, getting a second firewire card is recomnded. this
split the load on the bus.

ptgray knowledge base section is a must.
Maximum number of PGR IEEE-1394 cameras on a single 1394 bus

http://www.ptgrey.com/support/kb/index.asp?a=4&q=22&ST=

see also from unibrain-
FireWire bandwidth use of cameras
http://www.unibrain.com/download/pdfs/Fire-i_Board_Cams/camera_bytes_pkts_3Public.pdf
Multiple camera operation with Unibrain Software

http://www.unibrain.com/download/pdfs/Fire-i_Board_Cams/MultipleCamerasOperation1.pdf

On 4/19/07, Matthew Lewis wrote:
> One cheap approach we use often is to use a "color quad" security
> camera box, followed by an analog to digital converter. It’ll take
> four video camera inputs and pack them at quarter rez into one video
> output that you can then digitize/import into jitter (thanks
> tinapple). If 320×240 streams are "good enough" this is a cheap
> solution for getting four cameras into one firewire port – then you
> just need one more :) -matt
>
> On Apr 19, 2007, at 6:06 AM, jack keenan wrote:
>
> > Never done it with 5 but I’ve ran 2 unibrains a dv and isight at
> > the same time and it was fine.
> >
> > jk
> > On 19 Apr 2007, at 02:23, josh Powell wrote:
> >
> >> i need to get video from 5 cameras, i don’t really care what this
> >> does to the frame rate i just need to get it to work. i tryed dv
> >> cameras which i couldn’t get to function. i can get the computer
> >> to recognize 1 firewire camera and the isight but not even a usb
> >> dv camera. i read a lot about the unibrain cameras, but does this
> >> work? i would like to know that it works and generally how before
> >> i buy them. thanks a lot
>
> –
> Matthew Lewis
> Advanced Computing Center for the Arts and Design (ACCAD)
> The Ohio State University
> http://accad.osu.edu/~mlewis
>
>


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