periodically save it to a file(s)
is pix_write working in OSX yet? Are you talking about saving a chunk of video, or individual frames? I never tried using pix_multiimage to load an array of images files saved with pix_write the performance may not be all that great.
pix_write works in OSX. By default it writes out single high-quality photo-jpeg files into an image sequence which can be loaded into the QTPlayer.app and saved as a .mov file. The one caveat at the moment: using pix_write with pix_snap results in the images being flipped on the y axis. This is because QT and GL disagree on where to begin drawing pixmaps - QT starts in the top left, GL in the bottom left. I can add a flip function which will take care of this internally but it will affect speed somewhat. Currently I can record 640x480 scenes at 30fps (1ghz powerbook) using pix_snap + pix_write, but that might not be possible with the flip function in place. I will also talk to some people at Apple to see if there is a better solution to this.
It also wouldn't be too much of a chore to code up a QT movie recording object, but the soonest I could get to it would be next weekend.