using several displays with jitter/powerbook

Jan 25, 2006 at 8:44pm

using several displays with jitter/powerbook

hi,

can anybody give me some suggestions on have to run several displays from my powerbook. I’ve written several patches that works with live midi input and triggers jitter matrix algorithms. I had the idea for a long time to eg. trigger a tv set with a kick while projecting a 16/16 matrix that follows the main sequence, having another display following the hi-hat etc.. the problem is I want to have at least 3 or 4 projectors, tv sets, displays but the powerbook has only two built in display outs s video and DVI (I don’t even know, if you can use them simultenously).

I searched the web for a multi display card or an interface but didn’t come across anything like it
So…
any suggestions?
experiences?

any help will be much appreciated
thanks
furkan
furkan@sympatico.ca

#24107
Jan 25, 2006 at 9:21pm

couple options:

you can get an extra dvi/vga port with a Villagetronic ‘VTbook’
pccard – its not really fast enough for video work, but curiously, a
side effect of their driver is that it enables your built-in dvi AND
s-video outputting separate desktops, so it still functionally gives
you 2 external outputs

more crafty is the ’4 windows on one desktop method’ recently
discussed in the last couple of days, but basically you send a
1280×960 or higher signal to your DVI with 4 window ‘channels’ then
with hardware you need to:

DVI>VGA (adapter)
1×4 VGA DA (duplicated the signal 4 times)
4 scan converters with zoom and scale
zoom each scan converter to a different quadrant.
this gives you 4 s-video with 4 different channels.

the caveat: pushing 4 channels of ntsc/pal is alot of work for jitter
to do on a powerbook, so you must be very careful & good at
optimizing your patch.

a variation on the above is a 640×480 desktop with 4x 320×240.
Jitter can easily handle this on a powerbook.

its theoretically possible to scale the system to do 8 channels or
more of video out if you wanted, just adjust the vga output res and
the number of windows and their sizes accordingly. (plus more scan
converters, 1×8 DA etc)

deKam

#69265
Jan 25, 2006 at 10:24pm

first of all thank you for your response,
about the 4 (or more) windows on one desktop solution
how do I assign the window channels?
what is the VGA DA converter you mentioned?
and scan converters?
I searched for a discussion on 4 windows on one desktop but couldn’t find anything
if this has been discussed before I wouldn’t want to take your time, so it would be very helpful if you could send a link to that disc. or post some brief info on these

thanks again
Furkan

#69266
Jan 25, 2006 at 11:02pm

> how do I assign the window channels?

think of channels as separate jitter streams, displayed in 4 separate
windows, arranged in a 2×2 tile (or a single window with the 4
streams composited into quarters)

> what is the VGA DA converter you mentioned?

DA= distribution amplifier, copies 1 signal to many outputs

> and scan converters?

device that accepts a vga and converts the signal to legal ntsc or
pal video
(composite or s-video) most allow you to zoom in on a region of the
signal and scale it to the full size of the video output. prices
start at $100-$200, but you can pay $1000 for a good scan
converter. some projectors have the zoom feature built in as well,
which eliminates the need for the scan converter (if you are projecting)

dek

#69267
Jan 26, 2006 at 12:59am

well now that I understand it this idea seems beautifully simple but (after a little research) little expensive (the scan converters..). you mentioned the village tronic vt book today. any experiences with the card? you were suspicous about its performance with jitter. From what I understand the built in dvi and s video ports of the powerbook can’t be used simultaneously to output seperate dektops, without something like vt book/ is this true?

thanks again
furkan

#69268
Jan 26, 2006 at 1:51am

i do own a vtbook, and hardly use it (uhm… want to buy it?)
its mainly designed for the kind of person who wants two 23″ cinema
displays connected to their powerbook. unfortunately its opengl is
slow to the point of non existence, which is the main problem using
it with jitter. but yes, there is this surprising bug/feature that
it enables a separate desktop on the s-video and dvi simultaneously.

it might seem a little expensive to get 4 scan converters, but if you
compare it to the cost of what it ‘normally’ takes to do 4 channels,
multiple computers etc, it is more of a big savings than a big cost.
i would pursue this before the vtbook in my opinion

deK

#69269
Jan 27, 2006 at 7:36pm

I think i will save some money than go with the scan converters:)

here’s a summary of our discussion for others who might be interested..

to output to several displays, projectors from jitter/powerbook there are two main options

one is the vt book card by village tronic
http://www.villagetronic.com/
it has nearly non-existent opengl
but there is this surprising bug/feature of their driver that
it enables a separate desktop on the s-video and dvi simultaneously.

the second option is
*outputting a 1280*960 or higher signal to your DVI with 4 window ‘channels’

> how do I assign the window channels?
think of channels as separate jitter streams, displayed in 4 separate windows, arranged in a 2×2 tile (or a single window with the 4 streams composited into quarters)

*distributing the signal with a VGA DA

> what is a VGA DA converter?
DA= distribution amplifier, copies 1 signal to many outputs

*outputting the signals to scan converters and zoom each scan converter to a different quadrant (this is where it gets expensive)

>what are scan converters?

device that accepts a vga and converts the signal to legal ntsc or pal video (composite or s-video) most allow you to zoom in on a region of the signal and scale it to the full size of the video output. prices start at $100-$200, but you can pay $1000 for a good scan converter. some projectors have the zoom feature built in as well, which eliminates the need for the scan converter (if you are projecting)

and < >
you have 4 outs

the caveat: pushing 4 channels of ntsc/pal is alot of work for jitter to do on a powerbook, so you must be very careful & good at optimizing your patch.

a variation on the above is a 640×480 desktop with 4x320x240.
Jitter can easily handle this on a powerbook.

(it might seem a little expensive to get 4 scan converters, but if you compare it to the cost of what it ‘normally’ takes to do 4 channels, multiple computers etc, it is more of a big savings than a big cost. i would pursue this before the vtbook in my opinion)

many thanks to deK for sharing his knowledge
cheers

furkan

#69270

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