this should get you started with GEM in PD.

Im just making 2 separate rects to draw on. they arent really 'in
synch', but you can turn auto 1 off and control frame by frame
assuming they are the same length.
v a d e //
www.vade.info abstrakt.vade.info
On Jan 8, 2006, at 6:06 PM, lists.puredata.info@cefn.com wrote:
I'd like to control two separate projectors playing separate pre- recorded video in synchrony (dual head). Don't know which elements
are best to achieve this. Interested to know the components which I
should use as there are a few choices.I've prototyped some simple video control in GEM, on an OpenGL 3D
surface as described at http://www.agnula.org/documentation/ dp_tutorials/pd_gem/ and the rendering and control of frame speed
is perfect. However for the real thing I'll need dual head
rendering of two video files, and presumably rendering the frame
sequence to an OpenGL pixmap on a texture mapped surface is
unnecessary and itself could create some limitations for dual-heading.THE ALTERNATIVES
The basic questions are...
Video rendering : Gridflow vs. GEM vs. X. Serial comms : comport vs. serialctl vs. X.
Both dual head rendering and cross-platform serial communications
seem to be contentious issues, so I think it might be useful to
have ideas from those with experience of either or both of these
issues, and can recommend the libraries most likely to work for
both my prototyping and deployment environment. I hope to work out
the details myself, once I have an idea which libraries should work
in principle.Also if anyone has suggestions as to the strategy I should use to
get serial control data in from a Basic Stamp microprocessor, and
map two output video streams to two screens simultaneously, this
would be very useful.THE PROJECT
I want to emulate the front and rear window of a car, (footage
recorded from two DV cameras in a real car), on opposing projection
screens. The reason I'm keen on using PD is because I need to
control the speed of the video in real time as if controlling the
speed of the car's accelerator, from zero mph to full video speed
and above. Tried this with processing and it was very glitchy.I'm prototyping on Mac OS X but will deploy probably on an intel
machine running debian.Welcome your contributions.
Cefn http://cefn.com/curiosity/
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