I am working these days in an installation that mixes 4 videos at the same time. The amount of mixing is modified by the movements of people in the room (i will track their movement from above). I did some things that try to speed up all the process:
1)I roughly adapted a patch of video-mixing by Zachary Seldess (thanks!).
The uslider represents the person, you can move it.
2)Although I don't know much about open GL, somebody told me that it was a good idea to use it and to place some tasks in the graphic card instead of the processor. I use jit.gl.slab to mix matrices(??).
3)Loadram the 4 clips, in principle they are to be short, only 5 to 7 secs long
Still, my macbook coreduo 2.Ghz and 2GB RAM is doing badly (only 6 fps and less). This taking into account that I still have to do motion tracking with a firewire DV camera and cv.jit objects!!!
Any suggestion of how to speed everything up? I post my patch