Video - has anyone compiled/run GEM currently on OSX?
GEM for OSX is part of the CVS and you can find a binary here: http://taproot.dyndns.org/~cgc/downloads/index.html
The G4 version has a fair amount of Altivec code in it so definitely use that if you are using a G4. I will be posting an update to this version very soon, perhaps as early as today, so check the page for updates.
I need to play some avi/mpg/mov files in time with these midi/CV triggers too.
GEM for OSX uses Quicktime to open and play files so just about anything that the Quicktime player plays GEM will do the same. The exception is MPEG-1 clips which don't work and the QT documentation is wrong concerning the correct playback method - maybe this will get sorted out at some point.
You can always report bugs to this list and we will do our best to fix them for you.
cgc