[PD] Saving Gem output as video file on MacOSX ?

[Dudley Brooks]

I just recently started working with Pd/Gem.  I'm applying for a grant 
to combine it with my main art form (choreography).  I need to send a 
DVD of my experiments.  Is there a way to have Gem (or some accessory) 
save a Gem patch's output in some video file format?  This would be 
preferable to outputting it from the computer to external video (which I 
also don't know how to do) because at the moment the only external video 
I can output to anyway is VHS.

If there's no such thing in Gem/Pd, is there a way to do it in OSX 10.4? 
  (I also only just started working with a Mac, so I have a lot to learn 
there, too.)

Thanks.