Hi,

I was looking for a midi interface to control, bangs toggles, sliders and grids in my patches and I realized that a diy multitouch surface could do it and would be very adaptable.

However, before buying anything, I wonder about latency.
Would the latency of a system consituted of:

IR webcam + gem + [pix_multiblob 8-10] + [mtx_slicer] for each blob + no visual feedback

be low enough to play real time (i.e. ~10-50 ms) ?

thanks

camera tracking using a webcam always has latency of at least one sec (from my experience - with cheap stuff i admit) wich is already quite annoying. the only way i found to get adequate latency of, lets say, less then 200ms is to use a wiimote. it does the tracking onboard, and only sends the coordinates to the system. it has a 1024x768 ir cam for 35 EUR and tracks up to 4 points which should be sufficient.

let me know if you do it.
i pached the" move/rotate/scale something with 2 fingers" for a multitouch already.
and also i have a calibration script for glovepie wich makes a keystone correction and sends osc message to pd. you will need that.
i tried it on an lcd with 2 ir diods, but didnt build a multitouch jet.

I'm getting heaps of latency and audio distortion using dsp and GEM together. Is there any way to improve GEM's latency?

run gem and your audio processing in 2 instances of pd to avoid audio distortion

Could you explain how to do that on Mac please?

Or do you mean using the [pd~] object?

In Finder go to where pd-extended (I am guessing) is, ctrl+click and choose Show Package Contents then navigate to Contents/MacOS where you find Pd-extended. Open a terminal: In Terminal drug n drop the Pd-extended file and hit enter - cmd+T to open a second terminal drag n drop the file again and hit enter. You should have two instances of pd-extended.

You don't need to open the Terminal. Just double click the Pd-extended file and it should open a Terminal session and start a new instance of Pd automatically.

@sonsofsol said:

camera tracking using a webcam always has latency of at least one sec

i just got a ps3cam and tried it under ubuntu (without any drivers) and pdp_openCV - and its incredibly fast in terms of latency. id say something like 200 ms.
the only problem is the automatic exposure. i dont know how to turn it off wich spoils the fun a bit. maybee somebody can help?

Ok thanks.

So I've got two instances of Pd running. One for audio and one for GEM video. Now I have a problem.

I'm routing OSC data from a wacom tablet using OSCulator. But I can't create two instances of [udpreceive] because they're both running off the same port. So is there a way to get the second instance of Pd to read the data coming out of the first?

thanks very much =)