[PD] PDP and/or GEM for live video processing

Spencer Russell spencer.f.russell at gmail.com
Mon Jul 7 15:49:44 CEST 2008


I recently convinced the video guy for a play I'm sound designing to
use PD instead of Max/MSP/Jitter so that we can work together and run
the audio and video off of the same laptop. The problem is that I
don't have a lot of experience doing video in PD or using PD on OSX,
but I've been doing PD on linux for live audio processing for about 4
years.

He's done about a month's worth of research into using Jitter, so I
want to make the transition as easy as possible, and perhaps win
another PD convert. Mostly what we need to do is record video with
background subtraction, and then play multiple layers of it back with
some effects so that the actor can interact with himself. Is it more
computationally efficient to use straight PDP, straight GEM, or some
combination? I'd like to use GEM's [pix_video] object, because it can
talk to the OSX video system, but I'd imagine the PDP video processing
stuff is more efficient, as it's not concerned with texturing a
rectangle and displaying it in 3D. We're running the show on a Macbook
pro, so it's hardware accelerated. I've got the GEM<->PDP conversion
figured out in both directions using [pix_2pdp] and [pdp2gem].

Any OSX pitfalls I should be aware of? I don't have access to a
macbook pro myself, so I can't test things before I try to get it
working on his machine. Should I expect any problems from GEM display
or from the [pdp_glx] output?

thanks!

-spencer




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