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1 webcam on two computers

June 14, 2006 | 3:12 pm

Hi all,

I need to project the images from one webcam to two beamers.
Each beamer is connected to one powerbook.

I’ve never done this before.
I thought i’d use the udpsend and udp receive objects.

If i plug the output of jit.qt.grab to a udpsend object and plug the
corresponding udp receive to a jit.window on the
other computer, max complains and says :
jit.window : couldn’t get matrix object
I guess it’s because it’s on the other computer but…
what should i do ?

Can you help ?

Thanks.


June 14, 2006 | 3:21 pm

You should use jit.net.send/recv for sending video. Depending on your
network and video size, you might want to convert it to uyuv before
sending.

wes


June 14, 2006 | 3:33 pm

yeah thanks, that’s what i understood…
The only thing is that i don’t have jitter 1.5 here…
Do you think it’s possible without loosing image quality ?
Otherwise… i’ll have to get Jitter 1.5…
Thanks


June 14, 2006 | 4:19 pm

if you’re pre-1.5, there is also the jit.bixcp object set,
for download at http://www.bix.at/software/main_tools.html

if I remember correctly they only send 1 plane matrices, but you can
glue the planes together and cut them loose after receiving, depending
on the size you need: there’s a limitation to the maximum matrix size
having to do with the maximum size of the packets you can send, but
there’s all kinds of workarounds possible (sending r, g, b seperately,
cutting your matrix to pieces and assembling them etc.)

good luck,

Joost.

——————————————-

Joost Rekveld
———– http://www.lumen.nu/rekveld

——————————————-

"The mystery of the world is the visible, not the invisible"
(Oscar Wilde)

——————————————-


June 14, 2006 | 11:19 pm

On 14-Jun-2006, at 18:19, Joost Rekveld wrote:
> if you’re pre-1.5, there is also the jit.bixcp object set,
> for download at http://www.bix.at/software/main_tools.html
>
> if I remember correctly they only send 1 plane matrices, but you
> can glue the planes together and cut them loose after receiving,
> depending on the size you need

A few comments from the developer…

BIXCP is indeed a grayscale (in Jitter-speak: single plane) protocol.
The original jit.bixcp objects had an additional limitation based on
the hardware used for the "Medienfassade" at the Graz Kunsthaus (for
which BIXCP was designed). The Medienfassade was 64×25. Mind you,
those were *big* pixels.

The maximum pixel count was raised to just over 32,000 in the
commercial versions of the BIXCP objects, distributed with the Litter
Bundle for Jitter. The limitation was actually based on the maximum
amount of memory that Max could allocate on the fly at the time the
bixcp objects were ported to Windows. If there were a demand it would
now, I think, be possible to double that upper bound.

Hope this information is of use.

Best,
Peter

————– http://www.bek.no/~pcastine/Litter/ ————-
Peter Castine +–> Litter Power & Litter Bundle for Jitter

iCE: Sequencing, Recording & |home | chez nous|
Interface Building for |bei uns | i nostri|
Max/MSP Extremely cool http://www.castine.de

http://www.dspaudio.com/



wk
June 15, 2006 | 9:36 am

fire-i camera can send to 2 powerbooks at the same time (has 2 firewire
ports)
check http://unibrain.com/

wojciech


June 15, 2006 | 10:37 am

unibrain is excellent, its worth the 100$
full control from max (mac only)
screw mounted lens
daisy chain passthrough
i also bought a 10m cable from them.

i haven’t tried sending it to 2 outputs. from what i understand the
second firewire port on the unibrain is a pass through.
Kosma, have you tried this?
also, unibrain cameras can get there power from the firewire port or
from external dc , is power over firewire available on a powerbook FW
port?


June 16, 2006 | 12:43 am

Hello,
Only one cpu can grab it at a time. Its fun battling for it by
stopping and starting jit.qt.grab on the respective machines, but its
an either or not simultaneous proposition.
Barney



wk
June 16, 2006 | 9:59 am

yes, as i said it works for 2 computers,
at least for me…

wojciech


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