[PD] converting video patches from jitter

[Sciss]

hello,

i need some advise about a video processing lib i could use to  
convert some c'74 jitter patches. basically, the patches need to be  
running smooth on a medium speed computer, the libs should be free  
and open source and running on both linux and mac (intel). the stuff  
done in jitter is pretty basic and currently uses these objects:

jit.qt.movie				streaming movie files off harddisc ; note that the  
movies can be converted to any other movie format if necessary
jit.matrix					storing frames
jit.window				presenting movies
jit.scalebias				modifying r / g / b dynamics
jit.op					applying fadings
jit.alphablend			superimposing png images with transparency
jit.rgb2hsl and jit.hsl2rgb	animating de-saturation (to greyscale)  
and back to colour

as far as know, when using PD, there are these possibilities:

GEM		will allow me to play video files as openGL textures but not be  
doing matrix-pixel stuff?
framestein	windows only?
gridflow		looks as if this has a concept similar to jitter? says mac  
version is "experimental" ...
pdp			also looks like jitter, but more macro objects instead of low  
level when comparing to gridflow? says its linux + mac

also jitter already chokes with playing four small movies (cpu- 
nonintensive codec!!) on a fast macbook, so i hope to also reduce the  
"jitter" in the frame rate timing (images are only 12 fps but jitter  
seems to be really bad in keeping proper timing). to me it looks if  
either gridflow or pdp could be a good choice?

thanks for hints (also if there is something i could use outside pd,  
i'm gratefull for infos)! ciao,


-sciss-